CA2142875A1 - The use of h2 and h3 agonists to treat sexual dysfunction - Google Patents

Abstract

The present invention involves the novel use of various classes of drugs, such as H2 and H3 agonists, as erectogenic agents in the treatment of male and female sexual dysfunction.

Description

2 1 i 2 S~
wo 94/0412l~ PCr/BR93/0002 NOVEL COMPOSmONS
S ,.
F~ELD OF ~IE ~`~/~NTIC)N
The present invention involves the novel use of ~nous cl~l~ses of dru~s. such as HA
a~onists, as ereclo~enic ~gents in ~he u~a~nent of er~ctile dy~func~ion.

10 ~ACKGROUND C)F TH~ INVENTlON
The year t~2 markcd the beginning of ~ new er:~ in the dia~nosis and treatn-ent of male sexu~l impolence. At that ~ime, the new development was the u~c of papaverinc as a drug which, when injected in~racavernously, was capable of inducing ~ penile erec~ion in hum~ns, Virag, R. "ln¢acavemous injcction of pap~vcrine for erec~ilc f~ilure". Lance~ 2:
93g (] 982) nc6rctt~bly~ universal med~cal exper~ence wlln thlS ~rug over ~;evcr~l years revealed Ihc seventy of svme of its side~cffects, Junemalln, K.P. and Alken, P. "Ph.q~nacothcrapy of erectilc dysfunction; ~ review". ~ ], 71-g3 (1988). A major :~ disadvantagc of pa,~a~cnne wa~ the a~currcnce of unduly prvlon~ed crec~ion widl ~he dan~er 20 of pnapism. Pap~ver~ne ~as also ~ied in combination wilh t~c alpha sympathetie blocker phcntolan~ c. Z~)rgniotti, ~. W. and Lefleur, R. ~S. ~., 133(t): 39 41, ~1985).
Ph~noxybon~minc, ~ thcr dpha~ lrene~,rgtc blockcr was also tcsted, Brindley, G. S. ~r. J.
PsYchi~lrv. ~4~: 332 - ~i7 (198~5). The use of phenoxybcnzamine for the man~gcmenI of im~o~cnce was abandoned at tllis time becau~,e of cvidence obtaincd from expenmcll~s with 25 animals sug~esting that t~iis dru~ collld have- carcinogenic activit~. IA~C.
Phenoxyb~nz~minc and phen~xy~cnzarnin~. hydr~hl-oride. l~C ~y~
Risk Chem. Hum.. 24: 1~5 ~ 194, 1980; Hoffman, B. B., L~,fkowitz, R.J. Adr~ncrgic recoptor anlugonisl., Gt)odman and Gilman's;
- eighlh edition Ne-v York: Pcrgamon l'ress, CJ990. p. ~25.
Exl~erirncnts~with Cynomol~,u~ monkeys shc)wed Ih~t aflcr 1 to ~ weckly in~r~cavernous 1njccti~ns (of papaverine) lcd, ~flcr ~ period ()f 12 months, IO extcnsi~e fi~ro.,i~ in the dis~al arcas of the ercctile or~an~ ` ln hurnans~ this rcaction could havc ver~
~: negaliv~ long te~n consequences: fibrotic ccllpora _~vemosa ~ccome inc~pable of crection, Abo~,id, M. ct ~ . Urol., 132tS~: 1263 - 1~?`6~ g7).
~ I
~: ~
~ .

21-l2Q7~ `
wo 94~412~ P(~/BR93/00027 Jn~1986, Ishii et al injec~ed for thc ~Irst tirne pros~glandin E1 into human coTpora cavemosa f~1r the Ireatment of or~anic im~otence~ Ishii, N. ~1 "Therapeutic trial with pr~s~aglandin El for ~rganic impotence" lap ~ Im~., 1 54 - 9fi2 (19~6). See also lshii, 2~1 et al "In~racav~mous injection of pmstagl~ndin E] for the trea~nent of erectile impotence"
Ll~l . 14~ (2) 3~ - 325 (198~). Since it is a drug of n~tur~l occurrence in the body ~nd could be cxpected to cAuse fewcr side-effec~s than papaverine, PGE~ me rapidly and universally accepted, 311nemann, K. P and Alken, P ~m~Q~. ]: î ~ - 93 (19~8) The usc of a triplc combin~tion of PGEl. papaverine and phento~amine was introduccd in 1991. Bennett et al. J~ l~lrol . 146(O: 1564 - 1~65 (1991) However, 1() prolongcd erections h~ve be~n reported following thc use of such a combina~ion, von-Heydcn ct al. J Urol, 149(5 Pt 2); 1288 - 1290 (1~9~). The u~;e of prost~ ndin El is often rc3Octed by p~tients becausc of the painfulness of its injection W~ldhauser, ~ ~t al, Urol.. 140(~): 52~-527 ~19R~) ln spiI~ of initia~Iy promising evidencc~ of a possiblc role of nitIic oxidc (NO~ in ~he mechanics of nonnal human pcnile crection, Rajfcr, ~. ct al., N. Eng. J. Me~l., 326:90-94 (1~92) in lg92 Porst, (Por~t, H., ~nt. J. lmpotencc Rcs.. 4(Suppl. 2): A91 (19g2)) compared thc crcclOgCniC efficicncy Or ~ mg of SlN ~ (Linsindomin- Corvas31~)) a~inst 20 ~g of PGEI (Prostavasin~), both nf thcm adminislercd by intr~cavcrno~ls vias to 40 consecutivc padent complaining of erecdle failure. Accot~ing to the latt~r author: "... S~N-l 2() is considerably Icss effccuve than PGEI and will therefore, nc)t play ~ major role in the man~gcmcnt of male impotencc".
Virag, m ISJ~2, was thc first to dcmonstrate the crectogenic effect of a vasoactive drug injet:ted dircct!y ~nto the palicnt's epigastric artc~ The typc of thcrapy in which the pali~nts conduct their own trca~ment via intracavcrnous adrninis~ation of dru~g~ is called sclf-injecuon therapy. Virag,R. et al. ~lleioloev 35: 79 - 87 (1984). Sec ~Iso US patents 4, 127, 118; 4, 766,- 889~ d 4, 857, 0~9, ineorporated by hcrein referencc, in thcir entirety.
Altcn~ativc a~n~s, like acelylcholine (which causes m~rkcd sy~testlic effects bul only ~hort^lasting crections). a~i wcll as a numbcr of orally acling vasoac~iv~ substances such ~s yohin~billc, Terbutalin. bctanechol, levodopa, Vcrap~mil or theophyllinc have not bcen , ~C) succcssful for thc tseatmcnt of male cr~ctilc dysfunction.
Thcrc is a clear necd for the dcvelopment of ncw dru~s c~pable uf acting by in~ection or topical ~dm~ni~tration. as facilitators, potentiators and induccrs C~f full pcnil~ erection in .

2 i. ~ Q 7 ~
wo 94/~4120 PCr/B~93/00027 m~n, and have reduced or diminished side effec~s over the cunent mcthods of therap~ for the diagl)osti~ and therapeutic treatment of various ere~tile dysfunction`s in mcn.

D~AlLED DESC~l ~(~N OF THE lNVENTlO~' ~71e yre~;ent invcntion provides for the use of a histamine H~ r~ceptor a~onisl andfor a histamine H3 reccptor ~gOlliSt, or pharmi~ceulically acceptable salts thcreof, alone or in :ombination with other agents, for the treatment of ~rectile dysfunclion's in animals, and human bcings.
IIistamine and somc of it~ H2 and H3 a~onists rclax smooth musclc of ~he penile ~0 ussuc and thus exhibil desi~d diagnoslic and thcr~peutic acti~it~. Adaikan Çl ~1 showed that corpus cavernl)~um muscle of the human penis contains both Hl and ~12 histamine receptc~rs~ ln vitro, hista~ninc can causc thr~e type~ of effects on such muscle: a con~action in 62.5% of the cases; relaxation in 28.?s% and a biphasic ~spon~e of contrac~ion followed by relaxation. in 9.4% of thcm. The conlr~c~ile respc)nse of histamine is nnta~onized by mcpyraminc, an Hl reccptor antagonist, but not by prosta~landin antagonists, nor by phentol~min~. ~n cl-adreno~cep~or blcxkcr. Illc relaxant c~fect of histaminc ~vas selcctivcly : - blocke~ b,y burimamide, a ~elective H~-receptor antagontst, but no~ by propanolol, a ,B-adr~noreccptor bloc~er,:Adaikan ~, Euro. J. of Ph~n., 45, pp 261-265 (19~7).
: ~ ~ Tn 198a, Nahoum et al, Proceedings of the Third Biennial World Mecling on 20 Impotcncc, Bos~on, p,43, performed for thc first time, the intr~cavcrnous injection of histamhe in human beings. In an intriguin~ f~hion, in spit~ of the f~ndings of Adaikan et al, in vitro, it was found thal followin~ }ntracavernous ~dministra~otl, in the hum~n, histamine almosl inva~iably induccs colpuS ~avernosum smooth~ musclc to r~ n effcct expres~cd by tumesc~ ,c ~nd r~rti~l1 or full erection of lh~ orgnn. Thc abscncc oî ~ re~ponse or, alternatively, a disc~te, vory t~ansient cont~àction Or the org~n, were on~y rarcly observed.
}1uman tCS~illgt by intracavemous administration, shc~wed that histamine, with or withour concunent injection of phcntolamine, caused mar~;ed-pcni~e ercction of both, thc cavcmous a!ld ,the spongious bodies. Papa~verine in contrast, Icd only to cave~TIous body etcction, thcrefo~ eausing ~e ~lans pcnis to rema~n in lhc flac~id state~
Aill1ing ~t the neutralization of thc patient!s anxiety, exhi~l~ed ~s a conse~lucnce of ~be ~mticipation of a penile needlc puncturc, histamine was tned in combination with ~ulpiridc, a dopamincrgic D~ r~xcptor ~nt~onis~ posscssin~ tranquilizing actions. ~y i~seU, ~ulpiridc also produces penile tumescence and even crecnon, supportin~ the hypothcsis of b~ prescnce of D2-rcceptors in hum~n c~crnous smooth musclc fibers and/or 2142~7~ `

Wo 94t~4120 PCI/BR93/00027 hcir adrenergic n~rve term1nals. l he combmation of histaminc and sulpinde, enhanced the de.p~e and duration of pcnile rig~di~y .
~ :ur~er w~rk in this area. Ied to the hypothesis uhat histan-ine may bc a physiological, non-adrcncrgic, non-cholincrgic transmitter of human penile ereclion. Adaikan, P. G., in U'crld Book of ~mpotence, Ed. by Tom F. Lue. Smith-Gordon and Nishin7ura Co., 52 - 54, (1992).
The use of histamine itself is not ideal, ~l~hou~h it is surprisingIy frcc of undesirable colla~cral cffccts at either thc local or systcmic Icvel, f~llowing intracavernous injcction of dc~scs of histamine capable of inducing crectic~n, Nahoum Ct al, int. J. ~mpo~ence Rcs., 2, ~t~ Suppl. 2, 321 - 32~ (1990). His~amine ~Icases adr~nalino from supr~rrenaI glands by an H1 reccptor-mediated mechanism. Staskcws~ia-B~rczal;, J ~~L.~_~ha~. 2 (3~ 728-742 (1965); Wcst, G.B. PrR. I)n~ Rçs.. 2X:9-S2 (1984). Por this rcason,his~aminc injcction may be dangerous in hypertensive individual~, especially when aMicted ~ pheochrom~cyloma. ~urthermorc, by acting on Hl recep~ors in thc rcspiratory trcc, l~ histamine may cause bronchospasm in ~sthmatic pad¢nts, L~i~ienen ~La!, An-. Rev. respiran ~s. I 14, 291 295 (1976), Br~wn ~ J. Apr~ hvsi5)1. 42, 221 - 227 (1977).
lt should~ bc rcalized that frorn lhe viewpoint of its (hist.~minc's) usc a~ an crcctogcnic a~cnt, f~llowtng~intracavcntous injecuon. hist~minc binds, in alcalory fashion, both to Hl (cont~actilc~ and~H2 (r~laxin~rccep(ors. Thercforc. in theory, its dcsirable relaxing action will ~c partly orfully sct off by its simult~ncous contractilc effects. ~:
-Thc;existencc of H~ rcccptors in human skin, limits the concentra~ion of hiswninc which may: be- used- in a topical preparation. Thc dos¢ of histamine which must bc uscd to c~usc-~-express~ve-crcction will ~lso causc lhc organ to show signs of loc~! irrilation.
low~ver, tl~e usc of topical prep3rations o~ histamine in c()mbina~ n wittl anothcr agcnt whicb could~reduce tho amount of ~histamine necded would be of intcrest ancl is furthcr ~- ~: de.scribedhcr~in.'-Consequcnlly. ~hc present invention has found thal ~2 receptor agonists ~monstrates the same ;crec,to,6enic actions of hist~mine due to its 112 rcccptor ~ctivation '' ~ ' ' withoù~ thc ne~ativc sidc e~fects of histaminc and H1 rccep~or aClivity.
1) ''~ ~ Anothcr aspcct of the prescnt invention is thc use of a ph~nnaceulical composition i~
)f an H~ reaeplor agonist and ~ pharmaccutically acccplable carrier or diluent in thc uea~ment of. malc and female scxual dysfunction or impotencc. A prcferrcd pha~maceu~ical ;~ ~ composilion for use herein comprises tho ~12 a~onist, N-~2-(5 Methyl-4-201yl)mcthyl-thio)ethyl~- N'-~s-(4-imidazolyl)propyll-guanidine) and p h ~ r m a c e u t i c a I I y a c c ~ p ~ a b I c s t~ I t 5 ' . ~ ., , ~ ,. ...

WO 94/041~ L~ 2 ~ .~ PCl/BR93/00027 thereof (herein referred to as Impromidine). Preferred salt forms for use in the composition ;:
are the trihydrochloride, dihydrochlonde and dioxalate salts. .
A further aspect of this invention is the use of H2 receptor agonists in combination with at least one other therapeutically active agent. Such agents include other known 5 facilitating, potentiating agents andJor erectogenic agents, such as but not limited to those described below. A preferred H2 agonist for combination use herein is Impromidine and ;
pharmaceutically acceptable salts thereof . A preferred combination comprises and H2 agonist, such as Impromidine and at least one therapeutic agent seiected from sulpiride, ~ ~, papaverine, phentolamine, PGEl, histamine, phenoxybenzamine, an H3 agor~ist or an H
lo antagonist.
Initial studies with the selective H2-receptor agonists such as Impromidine and .
Dimaprit, which are practically devoid of activity on Hl receptors, have shown that they do not involve the drawbacks and limitations of the prior art agents, especially if the are .
associated with effective carriers for delivery. ~ .
Penile erection comprises three basi~ physiological mechanisms~
a) relaxation of the trabecular soth muscle of corpora cavernosa; b~ penile cavernous and ` ,.
helicine arteries dilation; c) b!ockade of penile venous blood outflow.
When injected by intracavernous via histamine clearly induces both erectile smooth muscle relaxation and penile arteries dilation. These effects can be easily demonstrated by `
20 duplex scan examination ofthe organ under this procedure. Aiming to verify if histamine as well as it's H1 agonist (2-(2-Aminoethyl)thiazole) and it's H2 agonist Dimaprit could exert some contractile ef~ect on human penile-veins, another group of in vitro experiments was done uti~izing surgical samples of deep dorsal veing of human penis. Neither histamine nor its referred H1 and H2 agonists exhibnitied any contracting activity on the material analyzed.
25 Nahoum et al., Itl. J.. Impotence Res., 2 (S~ippl.~)r321-322 (1990).
Suitable H2 agonists for use herein are described in US Patent No. 4,013,659~ and US 4,126,670 whose disclosures are incorporated herein by reference in their entirety.
The compounds of US Patent No 4?~13;659 are represented by the formula:
-.
HET- CH2SCH2CH2NH-C~=NH)-NH(CH2)3 -HET' (I) wherein -` - ~ ~
Het is a 4-imiæolyl, 5-methyl4-imidazolyl, 5-ethyl4-imidazolyl, 5-halogeno 1-imidazolyl, 2-thiazolyl, 3-isothiazolyl, 4-halogeno-3-isothiazolyl, 2-pyridyl~ 3-methyl-2-pyridyl. 3- .
ethyl-2-pyridyl, 3-halogeno-2-pyridyl, 3-hvdroxy-2-pyridyl, 3-methoxy-2-pyridyl or 3-ethoxy-2-pyridyl ring;

21~2~'1'3 ~
wo 94/04120 pcrlBRs3looo27 Het' is a 4-imidazole ring;
halogeno is bromo or chloro; or a hydrate or pharmaceutically acceptable salt or hydrated salt thereof.

Preferably Het is a thiazolyl or 5-methyl-4-imidazolyl. More preferably Het is 5-methyl 4-imidazolyl. Preferably the acid addition salts include those with hydrochloric, hydrobrornic, hydnodic, sulphuric, maleic and oxalate. Preferred salts are the hydrochloric and oxalate.
Specifically exemplified compounds of ~ormula (I) include 0 N-[3-(4-Imidiazoly})propyl]-N'-[2-(4-methyl-5-imidazolylmethyl-thio)ethyl]guanidine;
(also named herein as N-[2-(5-Methyl-4-imid~olyl)methyl-thio)ethyl]- N'-[3-(4-imidazolyl)propyl]-guanidine);
N-[3 -(4-Irnidiazolyl)propyl~-N'-[2-thiazolylmethylthio)ethyl]guanidine;
N [3-(4-Imidazolyl)propyl}-N'-[2-(4-imidazolylmethylthio)ethyl]guanidine;
N-[3-(4-Imidazolyl)pro~yl]-N'-L2-((5-bromo-4-imidazolyl)methylthio)ethyl]guanidine; l.
N-[3-(4-Imidazolyl)propyl]-N'-[2-13 -isothiazolylmethylthio)ethyl]guanidine;
N-[3-(4-Imidazolyl)propyl]-NI-[2-((4-bromo-3-isothiazolyl)methylthio)ethyl]guanidine; :
N-[3 -(4-Irnidazolyl)propyl~-N'-[2-(2-pyridylmethylthio)ethyl]guanidine;
N-[3-(4-Irnidazolyl)propyl]-N'-12-((3-methyl-2-pyridyl)methylthio)ethyl]guanidine;
20 N-[3-(4-Imidazolyl)propyl]-N'-[2-((3-bromo-2-pyridyl)methylthio)ethyl]guanidine;
N-[3-(4-Imidazolyl)propyl]-N'-C2-((3-chloro 2-pyridyl)methylthio)ethyl~guanidine;
N-~3-(4-Imidazolyl)propyl]-N'-[2-((3 -hydroxy-2-pyridyl)methylthio)ethyl]guanidine;
N-~3-(4-Irnidazolyl)propyl3-~-[2-((3 -methoxy-2-pyridyl)methylthio)ethyl]guanidine;
N-[3 -(4-ImidazQlyl~propyl]-N'-~2-((3 -ethoxy-2-pyridyl)methylthio)ethyl]guanidine;
2~ N-[3-(4-l~idazQlyl)propyl]-N'-[2-((3-ethyl-2-pyridyl)methylthio)ethyl]guanidine; and N-[3 -(4-Imidazolyl)propyJ]-N'-[2-(4-imidazolylmethylthio)ethyl]guanidine.

A preferred compound ls N-~3-(4-Imidazolyl)propyl]-N'-~2-(4-methyl-5-imidazolylmethyl-thio)ethyl]guanidine and salts thereof, preferably the di-and tri-30 hydrochhride- salts or the dioxalate salt, most preferably the tri-hydrochloride salt.

Compounds of US 4,126,670 are represented by the formula:

~ ~ CH2CH2CH2SC(=NH)-NH2 R2 (II) wo 94/0412~ 2 1 ~ 2 5~! 7 S pcr/BRs3/ooo27 wherein Rl and R~ may be the same or different and are methyl or ethyl, or the -pharmaceutically acceptable salts thereof.

Exemplified compounds of Formula (II) are:
S-[3-Dimethyl-aminopropyl]isothiourea; !", S-[3-Dimethyl-aminopropyl]isothiourea dihydrochloride S-[3-Dimethyl-aminopropyl]isothiourea dihydrobromide;
S-[3-(Ethylmethylamino)propyl~isothioureadihydrochloride; and o S-[3-~Ethylmethylamino)propyl]isothiourea dihydrobromide.

A preferred compound of fonnula (II) is (3-dimethyl-aminopropyl)isothiourea and pharmaceutically acceptable salts thereof, such as the di-hydrochloride salt also referred to -herein as Dimaprit.
-Suitable H3 agonists for use herein are those compounds disclosed in US Patent No.
4,767,778; 5,047,418; EP 338, 939 Al; WO 91/17146; EP 0 458,661 and EP 0 531 219 A1 whose disclosures are incorporated by reference herein in their entirety.

Compounds of US Patent 4,767,778 are represented by the formula:

~NHz wherein - - -R1, R2, R3 and R4 are each hydrogen or methyl, or R1 and R2 taken together represent a methylene, and R3 is hydrogen, a methyl or a carboxy with the proviso that R1, R2, R3 and 2~ R4 are not simultaneously methyl groups,: or a pharmaceutically acceptable salt thereof.

Exemplified compounds of Formula .~III) include the R and S (-)t(+) stereoisomers of:
a-methylhis~nine (also called 4-(-2~ninopropyl)imidazole; (R~=CH3 and R2, R3, and R4 = H) 3~ ~-methyl histamine (also cal}ed 4-(1-methyl-2-aminoethyl imidazole~; (R2=CH3 and R1, R3, and R4 = H);

21~25~7S
WO 94/04120 PCr/BR93/00027 ~"B-methyl histamine (also called 4-(1,1-dimethyl-2-aminoethyl imidazole); (R2 & R4 =CH3 and R1 and R3 = H), 2-~4-imidazolyl)-cyclopropylamine (R3 and R4 = H and Rl and R2 together form a methylene);
5 a-methylhistidine (R1=CH3, R3 is COOH, R2 and R4 are H); and the phannaceutically acceptable salts thereof.
Preferred is R-a-methylhistamine and salts thereof.

WO 91/17146 discloses compounds wherein the amine function of the compounds of ..
l0 Formula (III) is blocked to allow a bond which hydrolyzes slowly. Compounds of WO
91/17147 correspond to the formula: ~.

7 7 ~ R~ I
N/~R:Z IR1 (IV) wherem ~(~ R7 ,, , N~C
- 1~ Rl, R2, R3 and R4 are as described in Formula (III); and \R6 - iS a group hydrolyzable to the free amine.

Suitably, R5 is a cyclic aryl or heteroaryl group, optionally bonded to R6 and is optionally mono- or poly- substituted with R7; R6 is H, OH, CH3, O-alkyl, COOH or 20 C02alkyl, halogen, CF3, alkyl, or an aliphatic or cyclic chain, aromatic or not; optionally R6` shay be equal to R5~ and R7; R4 is H, OH, CH3, OR6, COOR6, halogen, CF3, or : optionally substituted alkyl; or pharmaceutically acceptable salts thereof.

. ` _ ~ .~ Exemplified groups of the hydrolyzable amine are:

-WO 94~04120 2 1 l~ ~ Q, 7 '1 PCl/BR93/00027 --OC~
OC~

N~ C~

0~ 1 .

~N ~ ~N8~ ~N_~}N(C02 N~

~,N; ;, ~ 1 Preferred salts herein for compounds of Forrnula (IV) include the hydrochloride or maleate salt. Preferred derivatives of histamine for use with the blocked arnine is (R) a-5 methylhistamine, a,a-dimethylhistamine-and a,~-dimethylhistamine, and in particular the a-R and ~-S forrns.
Suitably, R7 is OH, metho~y,. methyl, dimethylamino~ halogen or COOCH3 and R6 is phenyl, hydrogen or methyl; -Altërnatively, R7 is OH, methyl~ dimethvlamino, or halogen, and E~6 is hydrogen or methyl.
An exemplified compound offormula (IV) is (R)-(-)-2-[N-(lH-imida~ole-4-yl)-2-propyl]-(iminophenylmethyl)]phenol, and salts thereof.

WO 94/04120 2 1~ 2 ~ 7 5 PCr/BR93/00027 -10- , Compounds of US 5,047~418 correspond to the fonnula:
~CH2)2- ~NH
NH~N H2 (V) wherein X is CH2 or S; or a pharmaceutically acceptable salt thereo s Exemplified compounds of Formula (V) are:
S-~2-4(5)-imidazolyl)ethyl]isothiourea (X=S); and 4-(4(5) imidazolyl)butyramide (X=CH2) and salts thereof.

Pharmaceutically acceptable acid addition salts for use herein include hydrochloric, 10 hydrobromic, sulphuric, phosphoric, acetic, citric, maleic, lactic, ascorbic, fumaric, ;oxalic, methansulphonic and ethanesulphonic acids. I
~ ' Compounds of EP 0 458 661 correspond to the formula~
. ~ ~
-cH3 (C~2- S--C~
/=~ NH2 NH ,,N
(VI) a!so called N-methyl S-~2-(4(5)-imidazolyl)-ethyl]isothiourea and pharmaceutically acce~table salts thereof.
I
Com~ounds of EP 0 531 219 correspond to the formula:
C~)2- ~N

NH~N NH2 i~ ~ wherei~Xis-O or CH2, and the respective N-methyl derivatives thereof as well as N-- ~ methylated S-[2-(4(5)-imidazolyl)-ethyl]isothiourea and its N-methylated version and - ~ hydrates~or pharmaceutically acceptable salts thereof.

Other medicaments used to treat impotency or sexual dysfunction which may be used ` in combination with the ~I2 or H3 agonists include those well known to those skilled in thee art as well as those found in US Patent No.'s 5,190,967; 5,177,070; 4,663,318; 5,147.855;

WO 94/04120 2 ~ l~ 2 Q 7 tj PCI/BR93/00027 ~ ~

4,663,318; 5,145,852; 5,104,655; 4,931,445; 4,521,421; and WO 92/21346 whose disclosures are incorporated by reference herein in their entirety.

- Compounds of U.S. Patent No. 5,190,967 correspond to the fonnula:

¢~R

R2 (V) wherein R is hydrogen, or Cl 6 al}~l, C3 7 cycloalkyl C1 6 alkyl, C3 6 alkenyl, C3-6 alkynyl, C3 7 .`
cycloalkyl, arylCl salkyl, CHO;
Rl and R2 may be the same or dif~erent and represent hydrogen, halogen, C I 4 alkyl, C l 4 , aL~coxy, hydroxyl, cyano, nitro and NR3R4; , -R3 iand R4 are each independently hydrogen or alkyl;
X is o~ygen or - CH2-; or physiologically acceptable salts or hydrates thereof.

Exemplified compounds of formula (V) are: !
Trans -S-fluoro-2,3,3a,9a-tetrahydro-lH-[1,4]-benzodioxino [2,3-c]pyrrole, and its ;.
salts, preferably the hydrochloride salt, its hydrated form, preferably the hemihydrate form;
Trans -5-fluoro-1,2,3,3a,9,9a-hexahydro-[1]-benzopyrano ~2,3-c]pyrrole, its salts, preferably the hydrochloride salt, and its-hydrated and non-hydrated forms.

The use of galanthamine for treatment of physiologic and psychogenic mediated male erectile impotence is disclosed in US Patents 5, ~77jO70 and US 4,663,318.
Vasoactive intestinai peptide (VIP) and active fragments coupled to hydrophobic moleties thereof is disclosed in US Patent No. 5,147,855. Various long aliphatic carboxylic acid chains are attached to the N-terminus of the 28 amino acid peptide (VIP), such as 2~ CH3(CH2)16CO-, in particular steryl-VIP is prefelTed.
US Patent No. 5,145.~52 discloses a composition of papaverine, an a^blocker, a phoshopdiesterase inhibitor (PDE) and optionaily PGEI, a dopaminergic agent, and an atropinic agent (an anticholinergic agent). Suggested PDE agents are dipyridamol type ir~ibitors, and the suggested dopaminergic agent is piribedil, the al-blocker ifenprodil tartrate, yonimbine as an a2 blocker, and for the prostaglandin, alpostil is suggested.

2~4 2 ~
wo s4to4l20 pcr/BRs3/ooo27 US Patent No. 5, 104, 655 discloses polyunsaturated fatty acids in the form of mono-, di- and tri-glycerides or in complexes with natural or synthetic phospholipids. ln particular, ximenic or ximeninic acid alone, as a mono-, di- and tri-glyceride or phospholipid -complex is preferred.
US Patent No. 4,931,445 discloses the use of etoperidone and pharmaceutically acceptable salts thereof, specifically the hydrochloride salt for use in treatment of male sexual impotence.
US Patent 4,521,421 teaches the use of sulpinde to prevent sexual stimulate responses to erectogenic agents contrary the its use herein as an adjunct with histamine and o the H2 and H3 agonists.
PCT Patent WO 92/21346, published 10 December 1992 discloses the use of 3-morphonino-sydnoimine (Linsidomin), a nitric oxide donor, for the treatment of erectile dysfunction in both anirnals and humans. Linsidomin is an active metabolite of molsidomine, used in coronary heart disease and also a nitric oxide donor. Endothelium derived relaxing factor, believed to be a closely related substance to nitric oxide, have been recognized as important factors in the modulation of corporeal smooth muscle tone. Ignarro, L.J. et al, Biocbem. Bophvs. Res. Comm., 170: 843-850 (1990); Holmquist F., et al., Acta Physiol.
Scand.~ 141:441 442(1991).
Another aspect of the present invention for treatment of male and female sexual dysfunction in a anirnal, including human beings is the use in such treatment of an H3 agonist, or a pharmaceutical composition comprising an H3 agonist in a pharmaceutically acceptable carrier-or diluent. The H3 agonist used herein may also be administered in combination with a known, second therapeutically active compound. Therefore another aspect of the present invention is a pharmaceutical composition comprising an H3 agonist and at least one~addit10na~ therapeutically active agent in a pharmaceutically acceptable carrier or diluent for treatment of sexual dysfunctions in an animal. Such agents include, but are not limited to sulpinde, papaverine, phentolamine, PGEI, histamine, phenoxybenzamine , an H2 agonist,- or an Hl antagonist. Preferred H2 agonists for use as a co-administered agent is Impromsdine or Dimaprit, more preferably Impromidine.
_ _ :
-A "thefapeutically active compound" for use herein is a substances that work asfacilitators, potentiating agents and/or as erectogenic agents. Such agents include, but are not limited to, paracrine mediators such as prostaglandins and analogs thereof having vasoactive functions~ such as PGE 1 and PGE2, alprostadil and misoprostol: histamine;
3~ peptides such as calcitonin gene related peptides (CGRP) or vasoactive intestinal peptide wo 94/04120 214 2 Q 7 ~7 pcr/sRs3/ooo2/ ~-(VIP); calcium antagonists or blockers, such as nifedipin, verapamil, diltiazem, gallopamil~
niludipin, nimodipin, nicardipin, prenylamin, fendilin, terodilin, nisaldipin, nitrendipin orc ~`
perhexilin; a~adrenergic receptor blockers, for example, phentolam~ne, phenoxybenzamine, dibenamine, doxæosin, teræosin, tolazoline, præosin, trimazosin or minoxidil; adenosine, 5 ergot alkaloids, chlorpromazine, haloperidol, yohimibine; or smooth muscle relaxers, such as papaverine, the nitrates, such as nitroglycerin, isosorbide dinitrate, sodium nitroprusside or ;.
s-nitroso-n-acetyl-penicillin: dopaminergic receptor antagonists, such as sulpiride or alizapride; nitric oxide releasors such as molsidomine or linsidomin; cyclooxygenase ~
inhibitors such as indomethicin; and Hl antagonists, such as astemizole, cyproheptadine, -`
o diphendhydramine, hydroxyzine, cetirizine, mepyramine, chiorpheneramine, ~-brompheneramine, promethiazine, and pyrilamine. Also noted for being able to produce .
erections are the dopamine agonists such as apomorphine and bromocriptine and opioid - .
agonists such as naltrexone. S. La1 et al., Prog Neuro-Psychopharmacologv, 13, pp 329-339 (1989) and Fabbri et al., Psvchoneuro-endocrinolo~y, 14, (1/ 2), I03-111 (1989).
As used herein "erectile dysfunction" or "male sexual dysfuntion" refers to certain disorders of the cavernous tissue of the penis and possibly the associated fascia which ¦
produce impotence, the inability to attain a sexually functional erection.
As used herein "sexual dysfunction" refers to both male and female sexual 20 dysfunctions, and includes for women orgasmic dysfunctions related to clitoridal disturbances.
As used herein, "anirnals" includes mammals, preferably human beings, but also includes the areas of animal husbandry for which such treatment may be necessary, such as ;
but not limited to poultry farming.
2s METHODS OF ADMINISTR~TION ~ --The H2 and H3 agonists alone or in combination with additional therapeuticallyactive agents, such as facilitators, potentiating or erectogenic agents, may conveniently be administered by any of the routes conventionally used for such drug administration, for 30 instance, by injection, such as by intraca~vernoiis (also referred to as i.c.), intraurethral, such as by suppository or by gel, foam. Iotion, ointment, cream~ or sprays with direct administration into the urethra by any means available for such delivery, and by direct topical administratisn which include the same liniments, lotions, creams, ointments, foams, gels, pastes, drops, solutions, and sprays, as for intraurethral administration as well as a 3j transdermal systems.

21~7S
wo 94/04120 pcr/BR93/ooo27 The compounds used herein may be administered in such dosage forms may prepared by combining the H2 or H3 agonist with standard pharrnaceutical carriers according to conventional procedures. These procedures may involve mixing, granulating and compressing or dissolving the ingredients as appropriate to the desired preparation. It will 5 be appreciated that the form and character of the pharrnaceutically acceptable character or diluent is dictated by the amount of active ingredient with which it is to be combined, the route of administration and other known variables. The carrier(s) must be "acceptable" in the sense of being compatible with the other ingredients of the formulation and not deleterious to the recipient thereof.
Lotions according to the present invention include those suitable for application to the skin and for intraurethral use and may comprise a sterile aqueous solution which optionally contains bactericides, penetration enhancers, etc. and may be prepared by -methods similar to those for the preparation of sterile aqueous fonnulations and such methods are well known to those skilled in the art. Lotions or liniments for application to the skin, or intraurethrally, may also optionally include a moisturizer, such as glycerol, or oils, such as castor oil or arachis oil.
~rearns, ointments or pastes, according to the present invention, are semi-solidformulations of the active ingredient for external application to the skin or for intra-urethral use. They may be made by rnixing the active ingredient(s) in finely-divided or powdered form, alone or in solution, or suspension in an aqueous or non-aqueous fluid, and optionally utilize a greasy or non-greasy base. The base may comprise hydrocarbons such as hard, so~ _ or liquid~paraffin,-glycerol, beeswax, a metallic soap; a mucilage; an oil of natural origin such as almond, corn, arachis, castor or olive oil; wool fat or its derivatives or a fatty acid such as steric or oleic acid together with an alcohol such as propylene glycol or a macrogel. The formulation may incorporate any suitable surface active agent such as anionic, cationic or non-ionic surfactants, such as a sorbitan ester or a polyoxyethylene derivative thereof.
Suspending agents such as natural gums, cellulose derivatives or inorganic materials such as silicaceous silicas, and other ingredients such as lanolin, may also be included. Also the - ~ formulations may optionally include suitable penetration enhancer.
0 Dro~s according to the present invention may comprise sterile aqueous or oily solutions--o~suspensions and may be prepared by dissolving the active ingredient in a suitable aqueous or saline solution which may optionally include a bactericidal and/or fungicidal agent and/or any other suitable preservatives. and optionally include a surface active agent as well as penetration enhancers, stabilizers, antioxidants, etc. The resul~ing solution is then 3i sterilized in any suitable manner well known to those skilled in the art. One such manner wo ~4/04120 .~ 1 ~ 2 8 7 .~ PCI/BR93/00027 may be to clarify the solution by filtration, transfers it to a suitable container which is then sealed and sterilized by autoclaving or maintaining at 98-1 00C for about a half an hour.
Alternatively, the solution may be sterilized by filtration and transferred to the container by an aseptic technique. Exarnples of bactericidal and fungicidal agents suitable for inclusion in the drops are phenylmercuric nitrate or acetate (0.002%), benzalkonium chloride (0.01%) `
and chlorhexidine acetate (0.01%). Suitable solvents for the preparation of an oily solution include glycerol, diluted alcohol and propylene glycol.
Suitably, compounds of the present invention can be administered parenterally, that is by intramuscular or intracavernous administration . The intracavernous form of parenteral 0 adn~inistration are generally preferred. Appropriate dosage forrns for such administration may be prepared by conventional techniques requiring sterile formulations and packaging requirements. A parenteral application is preferred, since it is the safest way to directly apply a designated amount, without further adulteration by other factors~
A sterile, single use appiication is especially preferred for ease of applicatiqn, which, 1~ in addition to optionally containing sterile, disinfected swabs and enclosed usage J
information, single use injections also offer application ease and contains per dose, an effective arnount of an erection producing substance of an H2 or H3 agonist, preferably of Impron~idine. The needles used for single use prepared injections are primarily of the ultra thin variety, such as those used in insulin therapy. Also preferred are the self injection pens which are easier to handle.
The prepared injections may be kept in- light impermeable containers, if necessa~y.
For instance, the compounds of Formula (I), arelight sèn-sitive and should be kept such containers. They may also be developed in such a way so that the active ingredient and any second non-physically compatible second therapeutic agent~a&be mixed directly before the injection. This can take place, for example, in two containers, arnpoulès, or needles.
It is also possible to add photoprotective agents to the (parenteral) preparations if neccesaly. Several such photostabilizers are disodium edetate (EDTA), sodium ~
metabisulphite, sodium thiosulphate, di-methionine,-~sodium benzoate, glycerin, methyl paraben, glutathione, urocanic acid, thiourea, and sodium urate.
The application kits for the present invention may be single use or multiple use and may also contain additional therapeutic agents for inJection, topical or intraurethral application. The kits may contain single or multiple dose suppositories, for instance. which can be used for incremental increases in dosage to obtain the most effective dose for the individual and can contain one or more suppositories, or creams. or foam etc. of different 3~ therapeutic a~ents to enhance, or prolong. the desired effects.

21~2'~ 5 WO 94/n4120 PCr/BR93/0û027 Preparations for parenteral application can be packaged separately, for example in arnpoules or vials. Solutions containing the active ingredient are preferably sterile water or saline solutions, but may also be prepared as an emulsion, microemulsion or suspension.
The injection methods used herein can be offered fully prepared, or they can be prepared directly before use by mixing the active ingredients, for ex. the Iyophilics, with the desired solvent or suspension ingredients, if necessary, with additional solid carrier ingredients.
As noted, the preferred solvent or carrier is water, or saline or a combination solvent with is admixable with water. Such solvents include but are not limited to various alcohols, i.e. ethanol, or isopropyl alcohol, benzyl alcohol; 2-octyl dodecane, polyethylene glycol, 0 glycerin, propylene glycol and derivatives thereof, dioxane (diethylene dioxide3, dimethyl sulfoxide, dimethyl forrnamide, methylcellulsolve, cellusolve, and cyclohexanone, etc., are , ' suitable if not deleterious to the mamrnal.
Parenteral, as weU as topical for~ms may be sterilized and/or, if necessary, contain wxiliary mate~ials such as~preservatives, stabilizers, wetting agent, penetration enhancers, ¦
15 ~ `eniulsifiers, rdease~materials,~solwnt conductors, salts for the control of osmotic pressure, or~bu~ngandl rviscosityregu!ators.
Such additives are, for~ exarnple, tartrate and citrate buffers, ethanol, complexing agents, ~ EDTA (othylenediamine tetraacetic acid~ and its nontoxic salts~ To control iSC~Qgity, high~molecular polymas are suitable, for example, fluid polyethylene oxide, 20 ~ bo~cellulose,~ polyv=inylplylrodilone, dextran or gelatine. Solid carrier materials aré,~for ex2~1e, st~ch, lactose,~mannitol, methylcellulose, talcum, highly dispersed silicic acid,~high~molécul~ tty acids'~(wch~:as stearic acid), gelatine, agar-agar, calcium ¦ :
phosphate,- ma~nesium~stear2te,~ animal~and vegdable fats, solid, high molecular polyrners ' -(sucb~as polye~ cQl~
25 ~ Oily- suspension~sfor~pare I or~ topical~ uses may be synthetic vegetable oils such 'J"~ as liquid fatty acid~ esters, with Cg 22 atoms respectively in the fatty acid chains, for I :' example, palmitic jacid, ~lauric acid, tridecyl acid, margaric acid, stearic acid, oleic, linoleic, I
' ' ~ linolenic? arachi'dic'acid, myristic acid, palmitic, palmitoleic, behemic, gadoleic, linoleic acid, daidin ~acid, brasidi4 erucic wid Lignoceric or oil acids, which are esterified with one to ~` 30 ~ ~tlu~ typegf~l~ihols-which~carr~ 1 to 6 carbon atoms, for example, methanol, ethanol, proFanol,~butanol,- pentano! or its isomers, glycol or glycerol~ A fatty acid composition which~isllvailablécommerciallyisMYVEROL18-99. ' lso suitable are oils of varying viscosity such as the silicon oils~ or fatty alcohols, '~ such as' isotridexyl alcohol, 2-octyldodecane, cetylstearyl alcohol or oleyl alcohol, fattv acids' 35~ ~ :such~as~oieic acids. Furthermore, oils, such as natural or hvdro~enated vegetable oils, ~:

wo 94/04120 ~ ~ 4 2 ~ 7 5 PC~/BR93/00027 almond oil, cottonseed oil, peanut oil, or soybean oil, ethylene glycol, or fish oils containing primalily long-chain triglycerides; for example polyoxyethylene glycolated natural or hydrogenated vegetable oils, such as olive oil, sesame oil, peanut oil; hydrogenated castor oils; safflower or sunflower oils, or soybean oil may be used. The aforementioned materials have the characteristic of being spreadable, i.e. they are easily distributed on the skin.
Arnong the many suitable fatty acid esters useable herein are those oils contairung pnmarily medium chain fatty acid triglycerides,. such as the neutral plant oils, i.e., coconut oils, commercially available under the trade name Miglyol (BASF); Miglyol 810 and 8 l 2 -fractionated coconut oil comprising caprylic-capric acid tri~lycerides; Miglyol 818- a caprylic /capricAinoleic acid triglyceride; suitable caprylic-capric acid triglycerides such as those known under the trade name Myritol; or Captex 355 - a caprylic/capric acidtriglyceride; Other su~table agents are Captex 300, Captex 350, Captex 800, and Captex 850, all trade names available by Karlshams Lipid Specialties, Columbus OH); and Mazol 1400 (trade name available through Mazer Chemical, Gurnee, Il.); iso-propylmyristate, 7 isopropylpalmitate, isopropylstearate, PEG 6-capric acid,, polyoxyethylene glycerol trioleate, ethyloleate, waxy fatty acid ester such as artificial duck gland fat, coco fatty acids-isopropylester, lactic acids-ethylester, dibutylphtalate, adipic acid diisopropyl ester, polyol-fatty acid ester, among others; also useable are the propylene glycol mono-and di-fatty acid esters, such as propylene glycol dicaprylate, dilaurate, hydroxysterate, isosterate, laurate, ricinolate, etc., Especially preferred products of this class for use herein are the propylene glycol caprylic /capric acid diesters commercially known as Miglyol 840.
~-~ Combinations of gels are entirely possible for topical and-intraurethral administration.
In this case, ionic macromolecules are used, such as sodium carboxymethyl cellulose, poly~acrylic acid, polymethyl acrylic acid and its salts, sodium amylopectin semi-glycolate, alginic acid, or propylene glycol alg~nate for sodium salt, gum arablG, xanthin gum, guar gum or carrageen.
Use of film formers for topical administration are also possible, and as a film former, cellulose ether may be used, which dissloves in water as well as in organic solvents, and is similiar to hydroxypropylcellulose, methylcellulose, ethyl cellulose and soluble starch.
~
- Additional other ingredients may include - -~ - -i) lipids, such as phospholipids (which are optionally present in a liposome or a bilayer) which may be anionic, cationic or zwitterionic, in particular lecithins, such as soya bean lecithins, egg lecithin or egg phosphatide, cholesterol or long-chain fatty acids such as oleic acid;

2-~ ~2~.7~
wo 94/041~0 pcr/sR93/ooo27 - l 8-ii) stabilizers such as hydroxypropyl cellulose~ montmorillonite or colloidal silicic acid; Y
. . .
nl) antioxidants such as n-propyl gallate, butylated hydroxyanisole (BHA) and mixed isomers thereof, d-a-tocopherol and mixed isomers thereof, ascorbic acid, and citric acid 5 (monohydrate) iv) anti-microbials or preservatives, such as p-hyroxybenzoic acid ester, or benzoic acid (sodium salt), methylparaben or propylparaben;
v) other anionic surfactants such as bile salts and the alkali metal salts thereof, such as sodium taurocholate.

It may be necessary to use an absorption or penetration enhancers in the various ~`
compositions used herein. The absorption or penetration enhancers most preferably used in the compositions according to the present invention are the aliphatic sulfoxides of the -fonnula RSOR', wherein R is an alkyl, substituted alkyl, alkenyl, or hetero group containing lS up to 12 carbon atomsj and R' is a low molecular weight alkyl or hydroxy-substituted alkyl group. The most commonly used of these, is dimethylsulfoxide.
In the present invention, for dermal application, dimethylsulfoxide may be diluted with an~ appropriate diluent which may enhance acceptability of these compositions. For example, dimethylsulfoxide~glycerin solutions of 10% to 40% glycerin content may minimize 20 ~ skin irrituion both from the dilution of the dimethyl sulfoxide and the emollient, effects of t he glycerin, which tends to soothe the irritation and skin d~yness which may be caused by the dimethyl sulfoxide.
A ~numba of oth penetration enhancers can be used in the compositions accordingto the present invention. Am~ng these are optically active or inact*e pyroglutarnates of the - ~ ~ 2~ ~ ~ following fonnula H

O~_COOR ` ~;

wherein R is a linear, branched, or cyclic alkyl or alkenyl group having from 10 to 14 _ ~-; carbon atoms. These pyroglutamic esters are contained in large amounts in human skin, and~ ~~
are among the natural moisturizing factors in skin.
Among other penetration enhancers that can be used in compositions according to the present invention are glycerol monolaurate. dimethylacetamide, propylene glycol, or :, .

- 2142Q.7 ~
wo 94/04120 PCr/BR93/00027 ~:
!

_19_ '' other organic esters such as diisopropyl adipate or isopropyl myristate. Additional penetration enhancers for use in compositions according to the present invention include surfactants such as sodium laurylsulfate and polyoxyethylene-2-sorbitan monolaurate.
Another effective penetration enhancer for use in the present invention is 2-ethyl-1,3-s hexanediol either alone or in combination with oleic acid. Also suitable for use herein as a .
penetration enhancer are the bile acid salts and various modified bile acid salts.

Another group of compounds which are usefi~l in the present invention are penetra~ion enhancers of the formula 2 H~

wherein Rl and R2 are identical or different and each represents H, a C ~
C24 alkenyl, a (Cl 24 allyl) carbonyl or a (C2 24 alkenyl) carbonyl, provided that Rl and R2 are not H at the sarne time, or Rl and R2, taken together, may form a group of the following formula:
\C~R3 . / R4 - in which R3 and R4 are identical or different and each represents H, C 1-24 alkyl, or Cl 24 alkenyl.
A group of penetration enhancers which can also be used are the l-substituted azacyclopenten-2-ones, described in more detail in U.S. Pat. No. 43444,762 to Jajadhyaksha, which patent is hereby incorporated by reference. These compounds have the structural formula:

.
O
'R 11 ~C\ ' _.
m(H2C)--N--(CH2)n~ F~ --wherein R' is H or a lower alkyl g30up;
2s m is from 3 to 7;
n is from 0-1~; and R is CH3, phenyl~ substituted phenvl, or 21'~ 2~7S
wo 94/n~1~0 pcr/BR93/ooo27~7 - N--(cH2)m with the proviso that if m is 3 and R is--CH3, then n is not from 0 to 6. These compounds can be used either alone or with C3-Cs diols.

Amides ofthe formula (Rl)(R2)N-C~O)-R, wherein Rl and R2 are independently - selected ~om the group consisting of alkyl radicals and cycloalkyl radicals comprising from 1 to 20 carbon atoms and R is selected from the group consisting of alkyl radicals and cycloalkyl radicals comprising from I to 30 carbon atoms, and the total number of carbon atoms in the compound is at least 15 are also useful in the instant invention as penetration o enhancers. These compounds are described more fully in U.S. Pat. No. 4,808,414, to Peck et al., which patent is hereby incorporated by reference.

Sugar esters on combination with a sulfoxide or phosphine oxide can also be used to enhance penetration of the active ingredients These sugar esters include hydrocarbyl and alkyl polyoxyalkylene esters of cyclic polyhydroxy saccharides wherein at least one of the hydroxyl Foups on the saccharide moiety is substituted with an acyl or polyoxyalkylene group. These compounds are described in more detail in U.S. Pat. No. 3,8967238, to Smith, which patent is incorporated herein by reference.

Suitable ~ penetration enhancers for use herein include DMSO, bile acid salts, modified bile acid salts, propylene glycol and polyethylene glycol and analogs thereof.

The compositions of the present invention may be forrnulated into highly convenient dosage forms with thickening agents, including thickened solutions or lotions. ointments 2s (includmg crearns and gels), and the like.
Thickened solutions or lotions and ointments may be fonned by incorporating withthe penetration enhancer and the active in~redients, various gelling agents or other thickeners (vis~os1tyincreasers) which permit release of the active ingredients to the skin upon:application. These forrns are advantageously employed to lessen the runofffrom the ~ ~ ~ 3~ s~in that may occur with the more fluid composition forms. Importantly, they also permit -~ ~ more sustained contact of the penetration enhancer with the treated surfaces. thus enhancing . ~ ~ the speed of delivery of the active in~redients subcutaneously~ and providing more accurate :, : ' 2 ~ 4 ~ ~ 7 ~ pcr/BR93/ûoo27 wo 94/04120 -2~ -and controllable dosing. Accidental spilling and undesired contact with the material can also be minimized with these types of formulations.
It is advantageous to use water-dispersible agents (i.e., agents dispersible in water to forrn a homogeneous distribution or solution), such as the polyethylene glycols, as they are 5 readily compatible with water or other diluents to be formulated in the compositions, and they may be readily washed from the slcin following absorption into the skin of the active ingredients. Alternatively, an emulsion base may be used to impart the desired thickening effect, together with the emollient effect of the lipoid phase of the emulsion base, a better spreading and wetting effect and a retardation of any skin-drying effect of the penetration lo enhancing compounds. When compositions are formulated with an emulsion base, the penetration enhancer is incorporated in the water phase thereof. Another category of thickening base which can also impart an emollient effect is provided by lipoidal thickening agents which are soluble in the penetration enhancer.
The water-soluble thickening bases may use polyethylene glycols of di~erent lS viscosity's, depending upon the desired consistency and concentration of penetration enhancer and vasodilator and vasoconstrictor to be incorporated in the compositions. Other thiclcening agents include water-dispersible gums, carboxyvinyl polymers, methyl cellulose, sodium carboxyrnethyl cellulose, alginates, and the like.
Lotions and ointments incorporating emulsion bases may contain the usual 20 ingredients to provide the base, including fatty alcohols such as cetyl alcoholt emulsifiers, wetting agents and water.
Also, as noted above, the use of emulsifiers, or wetting agents may be necessary for the various formulations used herein? and include but are not limited to such agents as, sodium lauryl sulphate, fat alcohol ether sulfates, disodiurn-n-lauryl-,~im~no dipropionate, 25 polyo~ethylinized castor oil, or sorbitoan monooleate, sorbitan monostearate, cetyl alcohol, lecithin? glycerine monostearate, polyoxyethylene stearate, alkyl phenol polyglycol ether, cetyltrimethyl a~r~nonium chloride, or mono-/dialkylpolyg~ycol ether-orthophosphorus acid-mono-ethanolamine salts. ~
Pourable pharmaceutical dosages may be provided and dispensed in graduated 30 containers, or containers which contain a given volume? suc~ as-5 cc or the like. Containers with columns of 20 cc and above provide convenient multiple dosage forrns, and those containing a typical single dose, such as from about 0.5 g to about 10 grarns of a combination of vasoactive agent, vasodilator? penetration enhancer etc.~ and provide a convenient dosage form. Squeeze tubes for creams and ointments and cotton stick 35 appiicators may aii be used for ~opicri application of the thickened compositions 2142~7~
WO 94/04120 PCr/BR93/00027 `~
The compositions of the present invention can also be administered by spraying and misting such as from misting dev~ces and aerosol bottles, which containers are charged with fluid formulations containing at least 10% by weight of a combination of penetration enhancer, vasodilator, and vasoconstrictor, along with an aqueous diluent and, optionally, thickening agents, physiological salts, and the like. These compositions can be administered as either liquids or semisolid gels or mousses, depending upon the amount of gelling agents or surfactants included in the compositions. Compositions for this purpose are sufficiently fluid to permit dispensing by spray or rnist from the container, and also meet the necessary criteria for penetrability and avoidance of undue side effects.
0 With respect to administration of drugs directly into the penis, medicated catheters such as those described in US Patent 4,640,912 have been used; a nitroglycerin coated erection inducing condom is disclosed in US patent 4,829,991; transurethral administration of certain drugs is suggested in US patents 4,478,822; 4, 610, 868; 4, 640, 912 and - .
4,746,508; medicated urethral suppositories, inserts or plugs typically conta1ning anti- ¦ -lS infectiw agents or spern~icides is disclosed in US Patents 1,187,423; 2,584,166; 2,696,209 and 3,373,746; PGE2 as a self-administered gel, crearn or suppository for intraurethral - delivery is disclosed in Derwent abstract 93-045213105. Use of such delivery systems as defined above~for composhions of the instant invention is contemplated and the disclosures of said refences are incorporated by reference herein. PCT/ US91/02758 published as WO
- 20 91/16021, whose disclosure is incorporated by reference in its entirety herein, provides yet ' - another route for intraurethral delivery ~r drugs used to treat erectile dysfunction.
Standard suppl~sitory bases such as glycerin, the semi-synthetic glycerides, thehydrogenated triglycerides, commercially available as IV Novata, Massa Estarinum, Massupol and-suppocire~ are disdosed in the Handboolc of Pharmaceutical Excipents, `, 2~ American PhalmaceutiGal~ Assiociation,-(-1983) pp314-320 whose disclosure is incorporated by reference herein. The method of making such intraurethral suppositories (also called bougies) is well known to those~skilled in the art. Suggested suppos~) brands.
Alternatively, the:therapeutic agents may be applied to the penis in a layered manner.
This technique would require in one instance that the user first place an ointment or crearn, etc. having only the carrier~and.perhaps a penetration enhancer, to the area and allow it to remain there for a few mmutes. It would be wiped off and a second cream or ointment, etc., applied containing the primary agent would be applied. The initial presence of the carrier provides a physiological pathway of absorption for the agent to follow. Alternatively the first layer may contain both the carrier and active agent. and optionally a penetration enhancer and the second layer may contain a second therapeutic agent, for example \'VO 94/04120 ~ 2 ,Q 7 ~r; PCI /Br~93/00027 histamine or phentolamine. Such applications may be desirable if the two therapeutic agents and/or penetration enhancer are physically incompatible in same base.
Alternatively, a catheter or other such suitable device may be placed within theurethra and followed by introduction of the ointment, cream or suppository, etc. therein.
Suitably the catheter may have a means of attachment for a nlbe to be attached, preferably single dose administration, and extrusion of the tube contents into the urethra through said catheter would take place.
It is preferred that the agents be rapidly delivered through the urethra in order to bring about a rapid onset of the desired effect. The carrier should be a rapid releasing one to o allow for quick and consistent absorption of the active agent. The composition containing the active agents should contact the urethra along a surface area as large as possible, such as a 2-5 cm length, rather than a localized site along the urethra. Further, the composition should be applied at least 1 cm into the penis and past the point where the transition from the epidermal character of the glans has been completed.
IS It is further desired, in all dosage forms used herein which are inserted intra-urethrally that the volume of composition deposited in the urethra remain there until complete absorption of the active agent(s) have occurred. Volumes in the range of 50 to 100 mg (approx. 50 - 100 lul ) tend to exhibit spillage prior to complete absorption.
Accordingly, the amount of active drug containing compositions to be retained in the urethra is preferred to be about or below 100~,11 and more preferably about 50~
Adequate lubrication has been obtained with as little as 5-10111 oa lubricating- - ~ carrier, such as polyethylene glycol (PEG) 1000 and 1450. For intra-urethral administration, as noted above, the composition can be in the form of a fluid or semi-~uid - _sol~tion, suspension, dispersion, ointment, paste, cream, or gel which may also include many , -25 other excipients, including penetration enhancers, and buffering agents, as well as antimicrobial agents or preservatives for instance. All of these can be easily introduced into the urethra from a flex~ble tube, squeeze bottle, pump or aerosol spray in single or multiple - -- dose adrninistrations. The composition may also be contained in a rapidly releasing - supposito~ which melts and is absorbed at room temperature. See for example, _ 30 Remingtons, 18th Edition. WO 91116021 provides for devices to insert a suppository as . _ , . . .
: - _ weD as coating the exterior of the urethral suppositor, also disclosed are devices for delivery of ointments, pastes, etc into the urethra. Such devices and coatings would also be applicable to the instant invention herein.

,. . . .. . . .... . . .

21 ~ 2 ~ 7 S
:
wo 94/04120 PCr/BR93/00027 :.

The present invention may also be applied topically via a transdermal delivery system. One such delivery system is disclosed in US Patent No. 5,1 S2,997 whose disclosure is incorporated by reference herein in its entirety.
For use haein the parenteral (i.c.) dosage of an H2 agonist such as those disclosed in Formulas (I) and (II) herein, will be from about 5 mcg to 1,200 mcg per dose, preferably -~
from about 15 mcg to about 900 mcg per administration, and more preferably from about 25 mcg to 600 mcg. For use herein the parenteral (i c.) dosage of an H3 agonist without a second agent, will be about 1,500 to about 1~,000 mcg per dose, preferably from about 3,000 to about 12,000 mcg, and more preferably from about 4,500 mcg to 9,000 mcg.
0 If a second active agent, such as phentolamine or sulpiride is co-administered i. c. a reduction in the dosage of the H2 or H3 agonist is possiblè. It will also be appreciated by one of skill in the art that the optimal reduction in dose can be deterrnined by conventional techniques by those skilled in art. A suitable reduction in dose of the H2 agonist `-adn~inistered is expected and the dose, dependent upon the second agent co-administered, ¦ ~
15 ~;such as phentolamine, sulpride, or papaverine will reduce the dose to about 2.Smcg to 150 ? `~`
mcg~per adn~inistration, preferably about 10 mcg to 120 mcg per administration.
It will be r:ecognized by one of skill in the art that the optimal quantity the individual dosages -of the compaunds used herein will be determined by the nature and extent of the ! i`
condition being treated, the form, route and site of administration, and the particular patient !;
- 20 being treated, and that such optimums can be determined by conventional techni~ues by those skilled in art. The dosage to be administered is obviously dependent upon species, - body weight, age, individual condition and method of application. It will also be appreciated by one :of skill m the art that the optimal course of treatment, i. e., the number of - ~ doses given per treatment, the frequency of such treatment and the eventual duration of use can be ascertained by those skilled in the ar~ using conventional course of treatment determination tests.
Erection producing intracavernous doses of papaverine are typically in the range of , i about 7.5 to 160mg, for e.g. phentolamine in the range of about 0.1 to 10mg, and for PGE1 -in the range of 2.5 to 50 rnicrograms. Kurkle, et al., Urol.~Ln. of America, Vol. 15, No. 4, pp 625-629 (1988) and Ishii et al., J. Urol., Vol. 141, pp 323-325 (1989). Vasoactive =
intestinal peptides at doses of 10 to 100 ',lg have been used for producing erection upon -~
htracavernous injection.
Topical and intraurethral adrninistration of active agents typically require higher doses and as above for the prostaglandins, such as PGEI, papaverine, and the a -adrenergic agents, phentolamine, and phenoxybenzarn~ne are well known to those skilled in the art.

WO 94/04120 2 1 ~ 2 ~ 7 ' PCl/BR93/00027 Generally, the unit dosage application for PGE1 is in the range of from about 50 to 500~g, preferably from about 25 to 250,ug. For papaverine, the range of from about 1,000 to 25,000 mcg, for phentolamine, prazosin, and doxazosin they range from about 200 to I OOO~lg per dose with from about 50 to 2,000 ~lg being preferred. For VIP the range is s from 3 mcg to lOmcg; for the dopaminergic antagonists, sulpiride and alizapride from about 50 to 150mg. In combinations oftwo or more drugs, such as PGEl and the a-blockers tend to potentiate the erectile e~ect, thereby permitting efficacy to be obtained at a lower dose of both drugs.
In a combination administration it may be advisable to administer the two agentso sequentially rather than in one dosage form. Therefore another aspect of the instant invention is the sequential administration of an H2 or H3 agonist and a second therapeutic agent for the treatment of male or female sexual dysfunction. i -Use of intraurethral or topical administration o~the instant invention would allow for the lowest effective dosage of the histamine agonists particularly when used in combination I -with a second agent by allowing the patient to initially titrate himself to the dosage most effective for him by using the lowest dosage and repeating administration until the desired effect is obtained. Thereafter the patient would select an effective incremental dosage that is close the determined higher dosage or could continue with multiple lower doses or multiple co-administered agents. As noted in WO 91/16021 where small intraurethral suppositories are utilized, individual titration of PGE1 and prozasin were administered in multiple inserts. -- ~ Sirnilarly the H2 agonist alone or in combination with a second agent or optimally the -second agent would be in a second suppository to allow for incremental dosing as needed.
The arnount of active ingredient required for therapeutic effect on topical or - . intr~urethral administration will, of course, vary with the compound chosen, the nature and 25 -- severityof the condition ofthe animal or mammal undergoing treatment, and is ultimately at ~ the discretion of the physician or veterinarian. It will also be appreciated by one of skill in the art that the optimal reduction in dose can be determined by conventional techniques by ~ ~ those- skilled in art.
A suitable dose of an active ingredient for the H2 agonists and in particular of_~3~- -Formulas (I) or (II) is from about 50 mcg to 2,000 mcg for topical administration1 preferably om about 150 mcg to 1,500 mcg per administration, more preferably about 2S0 mcg to 1,000 mcg per administration. If utilized in multiple intraurethral suppositories, each suppository is preferably about 150 to 250 mcg each.
If a second active agent, such as phentolamine or sulpiride is co-adrninistered 35 topically or intraurethrally, a reduction in the dosage of the H2 or H3 agonist is possible. It 2l~2~'7~ ;

will also be appreciated by one of skill in the art that the optimal reduction in dose can be determined by conventional techniques by those skilled in art. However7 a suitable reduction in dose of the H2 agonist administered is expected and the dose, dependent upon the second agent administered, such as phentolarnine, sulpiride, or papaverine will be about 30 mcg to 1,500 mcg per adrninistration, preferably about 100 mcg to 1,000 mcg per adrninistration.
The terrn "co-administration" as used herein means both the sequential administration `
of one agent after another and the concomitant used together, i.e. contemporaneously. ~~
Another aspect of the instant invention is the co-adrninistration of an H2 agonist, such as Impromidine with histamine. Such co-administration of an H2 agonist will allow the dosage of histamine to be significantly reduced. The dosage of histamine used will be below ' `~
that which causes significant skin irritation, skin flushing and headaches, which have resulted .
~om the higher dosages of histamine.
The dosage of histamine when administered i.c. alone is about 30 to about 120 mcg per administration. The co-administration of histamine with Impromidine will reduce the I ,-amount of histamine necessary. Preferably about a 20% reduction in amount, eo about ¦ ~.
20mcg to 100mcg, more preferably about 45mcg to about 90 mcg. The co-administration of histamine with lmpromidine intraurethrally should result in similar reduction in dosage of Impromidine at about a 20% reduction in dose, frorn about 50 mcg to about 1,S00 mcg per .
administration .
If a third agent, such as phentolamine, papaverine, PGE1 or sulpiride is also administered the resulting dosage of histamine and Impromidine the reduction in doses of the H2/ H3 and histamine agents is ultimately at the discre~ion of the physician. The use of multiple intraurethral suppositories would allow for improved incremental dosing of both the :
H2 or H3 agonist with histamine and optionally a third agent such as sulpiride, papaverine, phentolamine, præosin, or PGEl .
.
FORMULATION EXAMPLES

Example l - Injection solution ;
Solutions of 50 mcglml of Impromidine trihydrochloride is dissolved in an isotonic solution and buffered to physiologic pH of 5.5 to 6 with sodium hydroxide. The solution is packaged in 0.5 ml or lml ampoules or any suitable size ampoules as may be necessary~
including multiple d~se vials.

wo 94/04120 2 1 ~ ~ ~` 7 ~ Pcr/sR93/ooo27 Similar solutions may be made using saline and/or sterile water optionally buffered with dfflerent agents. ~Iternatively the amount of Impromidine trihydrochloride may be varied to further concentrate or dilute the volume. In a similar manner to ~hese examples a different salt form, for instance the di-hydrochloride or di-oxalate salts may be utilized.
Alternatively the isopropyl myristrate my be substituted by squalesle oil, vitamin e and any low molecular weight, short chain alcohol including n-dodecanol may be used.

Example 2 - Solution for topical application o A solution for topical application is prepared having 200 mcg Impromidine dihydrochloride, 2 ml isopropyl myristate and 10 ml ethanol and packaged in 2 ml dosages.

Alternatively solutions for topical application may vary the amount of Imprornidine dihydrochloride to fi~rther concentrate or dilute the volume from 200mcg to 1 O,OOOmcg Impromidine. In a similar manner to these examples a different salt form, for instance the tri-hydrochloride or di-oxalate salts may be utilized.

Alternatively the isopropyl myristrate my be substituted by squalene oil, vitarnin e and the any low molecular weight, short chain alcholol inlcuding n-dodecanol may be used.
` -- - Example 3 - Transdermal patches - - 10 g linoleic acid and 90 g propyiene glycol are rnixed together. To this mixture, 200 mcg . Impromidine tri-hydrochloride is dissolved. Gauze squares, covered on one side with artificial~naterial, are then soaked in this solution and sealed in alurninum foil.
.
Altematively the linoleic may be substitued ~y oleic acid.

Alternatively the transderrnal application may vary the amount of lmpromidine tri-hydrochloride to fi~rther concentrate or dilute the volume from 200mcg to lO,OOOmcg 30 Impromidine. In a similar manner to these examples a different salt form, for instance the -- di-hydrochloride or di-oxalate salts may be utilized.

Example 4 - S~readable gel 94 g purified water is warmed to 10 degree Co and displaced with 500 mcg 3~ Impromidine hydrochloride. After adding 0.2 g p-hydroxybenzoic acid ester, 5 g 21 12~7~3 WO 94~04120 PCI/BR93/00027 .:

methylhydroxyethyl cell~lose is dispersed in the remaining solution. It is cooled by stirring.
After cooling, a hignly viscous gel is produced.

Alternatively one may valy the arnount of Impromidine tri-hydrocnloride to fiurther concentrate or dilute the volume from 200mcg to 10,000mcg Impromidine. In a similar manner to these examples a different salt form, for instance the di-hydrochloride or di-oxalate salts may be uti~ized.

Example 5 - Ointment 200 mcg Impromidine tri-hydrochloride is dissolved in a mixture of S g berzyl .
alcohol, 6 g isopropyl stearate, or in a similar arnoùnt of isopropylmyristate/isopropyl `-palmitater1sopropylstearate mixture, 10 g vinylpyrrolidon/ vinylacetate-copolyrner and 89 g isopropanol. The solution may be packaged separately for liquid application, or packaged as a spray with the usual propellants.
:
Alternatively one may vary the amount of Impromidine tri-hydrochloride to fi~rther concentrate or dilute the volume from 200mcg to 10,000mcg Impromidine. In a similar manner to these examples a different salt forrn, for instance the di-hydrochloride or di-oxalate salts may be utilized. If desired a different H2 agonist such as Dimaprit may be utilized, or alteratively a second therapeutic agent may be included. Such agents include histamine, R-a-methyl histamine or an H1 antagonist.
' Exarnple 6 - Oil-in Water.Emulsion In the usual fas'nion, a mixture is produced consisting of 200mcg Impromidine hydrocnloride, 9 g of a mixture of mono and diglycerides of palmitina~e and stearic acid, 3 g cetylstealyl alcohol with approx~ 12 mol ethylene oxide, 10 g 2-octyldodecane, 5 g thick p?raffin, 1 - 2 % benzy! alcohol, 500 mg PHB-ester and demineralized water.

As for the above 5 examples the amount of Impromidine may be varied from 200 to 10,000mcg and alternative salt forms may be used as well.

Example 7 - Li~ht cQnsistencY cream 200 mcg Impromidine hydrochloride, 4 g mono and diglyceride of palmitine and ~
stearic acid, 4 g cetylpalmitate, 1 g cetylstearyl alcohol with approx. 12 mol ethylene oxide, 1 g cetylstearyl alcohol with approx. 30 mol ethylene oxide, 5 g isopropylmyristate-wo 94/04120 2 ~ 't 2 , 7 5 pcr/sRs3/ooo27 /isopropylpalmitate-/isopropylstearate rnixture~ 0.5 g weakly bound polyacrylic acid of extremely high mg, 0. l l g sodium hydroxide 45 mg, 3 g glycerin, and de -mineralized water to lO0 g.

As in the above noted examples the amount of Impromidine may be var;ed from 200 to 10,000 mcg and alternative salt forms may be used as well.

Example 8 - Greaseless emulsion A mixture of 2.S g oleic acid decylester, 2.5 g isopropylmyristate, 4 g thin paraffin, o 0.9 g polyethylene stearate, 0.6 g sorbitan and glycerin fat acid ester are bonded at 70 degree ~' for lO minutes and stirred. The melted mKture is put in a 75 degree Co warm solution of 50 g demineralized water, 300mcg lmpromidine tri-hydrochloride and 100 mg allantoin and stirred, then cooled to 45 degree C. At this temperature, a carbopol film made up of lO g ethanol, 0.7 g carbopol 934 (weakly bonded polyacrylic acid) and 22.95 g de-mineralized water develops, which is removed with turrax, swelled to 2 h and neutralized with 0.1 5 g soda lime. Upon reaching 40 degree C, 1 g collagen is added. Finally, the raw emulsion is homogenized, if necessaly, a~er the addition of 0.6 g of perfiume oil, at 20 to 25 degree C in a high pressure bomogenizer.

As in the above noted examples the amount of lmpromidine may be varied from 200 - ~ - to 10,000 mcg and alternative salt forms may be used as well.

Example 9 - Gelatin solution _ For a gelatinous solution, 300mcg Impromidine hydrochloride, 150 mg gelatin, 4.7 2-5 mg phenol are topped offwith 1 ml of distilled water, placed in vials and filled to 1 ml.

As in the above noted examples the amount of Impromidine may be varied from 200 - ~ to 10,000 mcg and altemative salt forms may be used as well.

3Q - - Example 10 - Sprav In a mixture of 3 .5 ml miglyol 812 and 0.08 g ben2 yl alcohol, 200 mcg lmpromidine hydrochloride is suspended. This suspension is filled into a container with a valve. Then, 5 ml freon 12 is filled into the container via the valve, under pressure. By shaking, the freon-chlorinated cfc. is released into the miglyol-benzyl-alcohol mixture.

21f~`7~
wo s4/n4l20 pcrlBRs3/ooo27 -30~
, As in the above noted examples the amount of Irnpromidine may be varied from 200to 10,000 mcg and alternative salt forrns may be usèd as well.
..
Example 11 Oil-in Water Creams s a) 250 mcg Impron~dine is dissolved in a n~ixture of cetostearyl alcohol 7.2g, polyethylene i.
glycol 1000 monocetylether 1.8g, white petroleum, 15g., liquid paraffln 6g., purified water to 100g (and any necessary preservatives). Alternatively, 250 mcg of Dimapnt may be `~
used.
:
0 b) 250 mcg Impromidine is dissolved in a mixture of liquid paraffin 10g., cetostearyl alcohol 20gm., polyethylene glycol 1000monocetyl ether Sg, purified water to 100g (and any necessary preservatives). Alternatively, 300 mcg of Dimaprit or any of its pharmaceutically acceptable salts may be used instead.

c) 250 mcg Impromidine is dissolved in a mixture of cetostearyl alcohol 8.1g, sodium lauryl sulphate 0.9g, white petroleum 15g., liquid paraffin 6g., sodium phosphate 2.5g, citric acid monohydrate 0.5 g., purified water to 100g (and any necessary preservatives). ! `;
Alternatively, 300 mcg of Dimaprit or its phannacetically acceptable salts may be used instead.
As in the above noted examples the amount of Impromidine may be varied from 200 - -to l0,000 mcg and alternative salt fonns may be used as well. ~ ~

Example 12 Ointments a) 200 mcg Impromidine is added`to a mixtufe of Miglyol 812 Neutral oil 30gm., caprylic/capric/stearic triglyceride 40gm., white petroleum 10gm., and liquid paraffin 20gm.

b) 200 mcg Impromidine is added to a mixture of glyceryl cocoate and hydrogenated coconu~ oil and ceteareth 25, 43 gm., caprylic/capric/stearic triglyceride 29gm, Miglyol 812 l~
Neutral oil 18gm., and liquid paraffin 10gm. _ _~

As in the above noted examples the amount of Impromidine may be varied from 200 to 10,000 mcg and alternative salt forms may be used as well. --~vo 94104120 2 1 ~ 2 ~Q 7 ~f~ PCr/BR93/00~27 Example 13 - Intra-uret'hral suppositories Suitable suppository bases for inclusion with the active ingredients (which may vary but suitably include Impromi~ine firom about lSmcg to about 250 mcg per suppository and alternative salt fofnns) include:
a) Macrogel 6000 (50grn.), Macrogel 1540 (30gm) water and medicament (20gm);
b) Macrogel 6000 (47gm.), Macrogel 4000 (33gm.) water and medicament (20gm);
c) Macrogel l 000 (7Sgm.), Macrogel 4000 (25gm.), adjust for weight of medicament;
d) Witepsol S Suppository Base plus medicament;
o e) Witepsol H Supposito~ Base, Imwitor 742 2-3 gm, or up to 8g. plus medicament;
f~ Witepsol W Suppository Base, Imwitor 742, 2-3gm., or up ~o 8g plus medicament.

ln all of the above noted examples a second therapeutic agent may be added or alternatively the examples could be formulated using an H3 agonist such as R-a-methyl 15 histamine.

BIOLOGICAL DATA

20 IN nT20 EXPERrMENTS

- - Histamine action of Hl receptors:
The relaxing effect induced by histamine on segments of human corpora cavernosa in VitrQiS demonstrated in Figure l. The erectile tissue of corpora cavernosa was mounted in 25 ~ cascade and perfused ~Ith warmed (37C) and oxygenated (95% 2 + 5% C02) Krebs .
solution, as described in Vane, J.R. Brit. J. Pharrnacol., 23:360-373 (1964). Glyceryl trinitrate (GTN; S ~lg), acetylcholine (ACh; 20 lug), and histamine (HIST; 10, 30 and l00 - - ~lg) relaxed the human erectile tissue. During infusion with mepyramine ( 1 ~lM), it was - -: observed that the relaxing responses induced by GTN and ACh were not modified, while the = 3~ - relaxation induced by histamine was potentiated. This figure is representative of 3 - experiments.

- llistamine action of H2 receptors:
The effect of Cimetidine on relaxation caused by histamine on segments of human 35 corpora cavernosa in shown in Figure 2. The corpus cavernosum tissue was mounted in 2142~7~ ;~
wo 94/04120 PCr/BR93/00027 cascade and perfused with warmed (37C) and oxygenated (9S% 2 + S% CO2) Krebs solution, as described by Vane, supra. Glyceryl trinitrate ~GTN; 1 and 10 ~g), acetylcholine (ACh; 20 llg), and histamine (HIST; 30 ~lg) relaxed the human erectile tissue. During infusion with Cimetidine (5 IlM), it was observed that the relaxation induced by GTN and s ACh was not modified, while the relaxation induced by histamine was markedly inhibited. In the simultaneous presence of Cimetidine (S or 10 ~lM) and mepyramine (1 ~M), histamine still produced a decreased but def~nite relaxing response. This Figure is representative of 3 experiments.

lo Histamine action of ~3 receptors:
The effects of both R-a-methylhistamine (an H3 agonist) and thioperamide (an H3 antagonist) on strips of huan corpora cavernosa smooth muscle are shown in Figure 3 . The ~`
corpus cavernosum tissue was mounted in cascade and perfused with warmed (37C) and , oxyFn~lted (95% 2 + 5% CO2) Krebs solution, as described in Vane, supra. Glyceryl IS trinitr~lte (GTN; 200 ng), acetylcholine (ACh; 1 nM), and R-a-methylhistamine (R-a-M~HIST, 200~M) caused relaxation of human corpus cavernosum erectile tissue. Themaximally effective ;dose of 100 ~lg of R~-Me~ST had a considerably smaller relaxing ¦ ..
effect than l~g of histamine. Neither mepyramine (l,uM) nor cimetidine (5,uM) altered the effect of R-a-Me~ST. Thioperamide, a specific blocker of H3 histamine receptors,decreased but did not fi~lly block the responses of human cavernous erectile tissue to R-a-MeE~ST. Thisfigureisrepesentatiwof2expe_iments.

IN VIVO E~PERlhENTS
2S ~
~: The erectogenic activity of histamîne alone or in combination with phentolamine was compared to that of papaverine. These effects were studied in four patients having psychogenic and four patients having erectile disfunction of organic ori~in. The patients - ~ were submitted in consecutive fashion to respectively: the vehicle of the preparations (5% ~.
mannitol in phosphate buffer); papaverine (60 mg); histamine hydrochloride (30 and 60 ~g); -and these same doses of histamine in combination with 5 mg of phentolamine mesylate.
~: The control injection were innocuous; histamîne alone produced erectogenic activity ~ ~ markedly lower than that due to papaverine, both in terms of the intensity and duration of ; ~ the responses. Nevertheless, when associated with phentolamine, histamine proved to evoke 35 erections similar to erections reported by the patients during sexual intercourse.
.

wo 94/04120 2 1 4 2 ~ 7 ~ PCl/BR93/00027 In none of the cases studied did histamine cause unduly prolonged erection, having a maximal course of action of 3 hours. The association of histamine with phentolam~ne :
benefited mainly the duration of histamine erection. The erectogemc effects resulting from the association of histamine with sulpiride ( 100 mg) were similar to those obtained with ~he 5 use of histamine associated with phentolamine (5 mg); however, sulpiride plus histamine produced a 10% greater degree of penile rigidity and a 20% longer duration of the response.
Hl antagonists (mepyramine or chlorpheniramine, 20-I00 ug) potentiated the erctogenic effect of histamine in a manner similar to that caused by phentolamine. This similarity points towards the usefulness of the substitution of a-adrenergic antagonists, like 10 phentolamine, by Hl antagonist, when using histamine or its H2 or H3 agonists as primary erectogenic agents.

Effects of intracavernous injections of Dimaprit in monkeys 10 llg of Dimaplit dissolved in 25~ ,ul of distilled water were administered to 5 tufted 15 ear marmoset (Callithrix jacchus geoffroy) either alone or in combination with 200 ,ug of phentolamine. This procedure invariably evoked an erectile response which was clearly intensified when the drug was administered with phentolamine .
Such results suggest the potential usefulness of Dimaprit as an erectogenic drug in the management of human erectile dysfunction, both alone or in combination with other 20 secondary potetianting agents, such as histamine, H3 agonists, Hl antagonists, a-adrenergic blockers, D2-receptor antagonists, NO-donors, VIP and others.

Effects of intracavernous injections of lmpromidine in monkeys Nine adult monkeys of the Callithri~ genus were anesthetized with ketamine (10 25 ~ -mglkg)~and diazepam (0.3 mg/kg). Maximum volume injected was 0.3 ml.
- - ~ Three animals were given 3.5 llg of only Impromidine. Responses were nil, partial or full in each ofthe animals. Six anlmals were given 3.5~g of Impromidine in combination withl 200 ~ug of phentolamine. In 3 of such animals the erectile responses varied between 6û
- to 80% of maximum. The remaining animals presented full erections. ln all but one animal 30 responses lasted between lO and 40 minutes. The last animal remained in filll erection for 3 hours.
- - _ Effects of intracavernous injections of Impromidine in human volunteers Like the expenmental animals, all human subjects showed some degree of erectile 3S response when submitted to lmpromidine injection by the intracavernous route. The 216~2~7~3 `
WO 94/04120 PCl/BR93/00027 responses were as follows: 1 patient who received 60 ~,lg of Impromidine alone showed a~er 10 minutes 70% of his maximal peniie rigidity. This response was maintained for 40 minutes. Ofthe 3 patients receiving 30 mcg of Impromidine in combination with 2.5 mg of phentolarnine, 2 showed 70% of the maximal penile response and 1 patien~, 40% of his also maximal response. A 70% degree of rigidity is usually sufficient for penetration; 40% is not. In 1 patient 30 ',Ig of Impron~idine was adn~inistered in association with 100 mg of sulpiride and penile tumescence was the only response observed.

Ef~ects of intraurethr~l adminstration of Impromidine in men o The intraurethral administration of Impromidine (Z00 ~g) together with 500 ~lg of phentolamine dissolved in a mixture of 5% manr~itol and 5% DMSO was performed in 9 individuals: 7 no~nal volunteers and 2 impotent patients. 0.7 n~ of the drugs' mixture were instilled into the urethra using a 1 ml plastic seringe fitted with a pippete-type tip. Following instillation, the ~uid outflow was prevented by temporarily sealing of the urinary meatus with derma~ adhesive tape which was kept in place until a definite erectile response was observed, or for a maximal period of 90 minutes.
Full erection was observed in 4 individuals; partial response was noted in 5, one patient exhibited only tumescence. Responses became apparent after 30 to 90 minutes according to the patient. Durations varied between 15 and 60 minutes.
It should be noted that the treatment was given twice to one of the patients Hisresponses were essentially identical.
Control experiments in which the drug's vehicle only was applied, gave uniformlynegative results.
In an additional group of patients studied, the mixture of S00 ug of histamine plus 500 ~g of phentolamine administered by the intraurethral route produced comparable results.
In summary, the above considerations lead to the conclusion that: a) histamine, as well as its H2 agonists, particularly Impromidine, exhibit erectogenic activity of diagnostic and therapeutic value in the management of erectile dysfunction in mammals; b) such agents ¦
activity is potentiated both regarding its intensily and duration, by concurrent or sequential administration of adequate secondary agents; c) these agents, alone or in combination, showed adequate pharmacologic activity by either intracavernous and topical, mostly transurethral or transbalanic application; d) H3 agonists, alone or in combination urith other secondary agents, must be considered as being able to facilitate, potentiate or induce fi~ll penile erections in mammals.

wo 94J04120 2 1 4 ~ Q 7 S PCr/BR93/00027 = ~

The above description fiully discloses the invention including preferred embodiments thereo Modifications and irnprovements of the embodiments specifically disclosed herein are within the scope ofthe following claims. Without filrther elaboration, it is believed that 5 one skilled in the art can, using the preceding description, utilize the present invention to its fullest extent. There~ore the Examples herein are to be construed as merely illustrative and not a limitation of the scope of the present invention in any way. The embodiments of the invention in which an exclusive property or privilege is clairned are defined as follows.
i`

.-. .

.. ,,

Claims (30)

What is claimed is:

1. A method of treating sexual dysfunction in an animal In need thereof which comprises administering to said animal an effective amount of an H2 agonist.

2. The method according to Claim 1 wherein the H2 agonist is a compound of the formula Het-CH2SCH2CH2NH-C(=NH)-NH(CH2)3- Het' (I) wherein Het is a 4-imiazolyl, 5-methyl-4-imidazolyl, 5-ethyl-4-imidazolyl, 5-halogeno-4-imidazolyl, 2-thiazolyl, 3-isothiazolyl, 4-halogeno-3-isothiazolyl, 2-pyridyl, 3-methyl-2-pyridyl, 3-ethyl-2-pyridyl, 3-halogeno-2-pyridyl, 3-hydroxy-2-pyridyl, 3-methoxy-2 pyridyl or 3-ethoxy-2-pyridyl ring;
Het' is a 4-imidazole ring;
halogeno is bromo or chloro; or a hydrate or pharmaceutically acceptable salt or hydrated salt thereof.

3. The method according to Claim 2 which is N-[3-(4-imidazolyl)propyl]-N'-[2-(4-methyl-5-imidazolylmethyl-thioethylguanidine or a hydrate of pharmaceutically acceptable thereof.

4. The method according to Claim 1 wherein the H2 agonist is of the formula:

(II) wherein R1 and R2 may be the same or different and are methyl or ethyl, or the pharmaceutically acceptable salts thereof.

5. The method according to Claim 4 wherein the compound is (3-dimethyl-aminopropyl)isothiourea and pharmaceutically acceptable salts thereof.

6. The method according to Claims 1 to 5 wherein the H2 agonist is used in combination with one or more therapeutically active agents selected from an H3 agonist, histamine, an .alpha.
-adrenergic blocker, a dopamine D2- antagonist. nitric oxide releaser, prostaglandin or an analog thereof having a vasoactive function, calcium antagonist, CGRP, VIP, phentolamine, physiostigmine, neostigmine, hydralazine, sodium nitroprusside, phenoxybenzamine, or an H1 antagonist.

7. The method according to Claim 6 wherein the second agent is administered sequentially or contemporaneously with the H2 agonist.

8. The method according to Claims 6 or 7 wherein the second agent is phentolamine, phenoxybenzamine, histamine, H3 agonist, H1 antagonist, PGE1 or sulpiride.

9. The method according to Claims 6 or 7 wherein the agonist is Impromidine or Dimaprit.

10. The method according to Claims 1 to 9 whereby the method of treatment is by intracavernous injection, topical, transdermal, or intraurethral administration of the H2 agonist.

11. The use of an H2 agonist in the manufacture of a medicament for the treatment of sexual dysfunction in animals comprising an effective amount of an H2 agonist and a pharmaceutically acceptable carrier or diluent.

12. The use according to Claim 11 which further comprises a second therapeutic agent which either facilitates, potentiates or is erectogenic.

13. The use according to Claim 10 wherein the second agent is selected from an H3 agonist, histamine, an .alpha.-adrenergic blocker. a dopamine D2- antagonist, nitric oxide releaser, prostaglandin or an analog thereof having a vasoactive function, cycloxygenase inhibitors, calcium antagonist, CGRP, VIP, phentolamine, physiostigmine, neostigmine, hydralazine, sodium nitroprusside, H1 antagonist, or phenoxybenzamine.

14. The use according to Claim 13 wherein the second agent is an H3 agonist, sulpiride, papaverine, phentolamine, or histamine.

15. The use according to Claim 13 or 14 wherein the H2 agonist composition is administered by intracavernous, topically, transdermally, or intraurethrally.

16. The use according to Claims 11 to 14 wherein the composition further comprises a penetration enhancing agent.

17. Unit dose packaging of a single use. i.c. injection , a single use topical administration or a single use intraurethral administration wherein said unit dose packaging contains an effective amount of a parenteral, topical or intraurethral dosage of an H2 agonist that promotes erection.

18. The single dose package, according to Claim 17, which further comprises a second therapeutic agent.

19. The unit dose package according to Claim 17 wherein the H2 agonist is Impromidine and is administered intracavernous in an amount from about 25mcg to about 600 mcg.

20. A method of treating sexual dysfunction in animals in need thereof which comprises administering said mammal an effective dose of an H3 agonist.

21. The method according to Claim 20 wherein the H3 agonist is of the formula (III) wherein R1, R2, R3 and R4 are each hydrogen or methyl, or R1 and R2 taken together represent a methylene, and R3 is hydrogen, a methyl or a carboxy with the proviso that R1 , R2, R3 and R4 are not simultaneously methyl groups, or a pharmaceutically acceptable salt thereof.

22. The method according to Claim 21 wherein the compound is R-.alpha.-methylhistamine or a pharmaceutically acceptable salt thereof.

23. The method according to Claim 22 wherein the H3 agonist is used in combination with one or more therapeutically active agents selected from an H2 agonist, histamine, an .alpha.
-adrenergic blocker, a dopamine D2-antagonist, nitric oxide releaser, cyclooxgenase inhibitors, H1 antagonists, prostaglandin or an analog thereof having a vasoactive function, calcium antagonists, CGRP, VIP, phentolamine, physiostigmine, neostigmine, hydralazine, sodium nitroprusside, or phenoxybenzamine.

24. The use of an H3 agonist in the manufacture of a medicament for the treatment of sexual dysfunction in animals comprising an effeftive amount of an H3 agonist or a hydrate or a pharmaceutically acceptable salt thereof.

25. The use according to Claim 24 which further comprises a second therapeutic agent which either facilitates, potentiates or is erectogenic.

26. The use according to Claim 25 wherein the second agent is selected from an H2 agonist, histamine, an .alpha.-adrenergic blocker, a dopamine D2-antagonist, nitric oxide releaser, prostglandin or an analog thereof having a vasoactive function, calcium antagonists, CGRP, VIP, phentolamine, cyclooxgenase inhibitors, H1 antagonists, physiostigmine, neostigmine, hydralazine, sodium nitroprusside, or phenoxybenzamine

27. The use according to Claim 26 wherein the second agent is an H2 agonist, sulpiride, papaverine, PGE1, phentolamine, or histamine.

28. The use according to Claims 24 to 27 wherein the composition is administered intracavernousm, topically, transdermally, or intraurethrally.

29. The use according to Claims 24 to 28 wherein the composition further comprises a penetration enhancing agent.

30. Unit dose packaging of a single use i.c. injection , a single use topical administration or a single use intraurethral administration wherein said unit dose packaging contains an effective amount of a parenteral, topical or intraurethral dosage of an H3 agonist that promotes erection.