CA1296633C

CA1296633C - Controlled release bases for pharmaceuticals

Info

Publication number: CA1296633C
Application number: CA000538065A
Authority: CA
Inventors: Benjamin Oshlack
Original assignee: Euro Celtique SA
Current assignee: Purdue Pharma LP
Priority date: 1986-07-18
Filing date: 1987-05-27
Publication date: 1992-03-03
Anticipated expiration: 2009-03-03
Also published as: FI872917A0; KR880001285A; ATE62404T1; JPS6330427A; FI872917A; JP2661646B2; CN87104429A; JPH09136845A; NO872989D0; FI87045B; AU596183B2; ES2033259T3; DZ1112A1; IL82604A0; JP2511054B2; MX163284A; DE3769221D1; PT85353B; IN166546B; FI87045C

Abstract

CONTROLLED RELEASE BASES FOR PHARMACEUTICALS
ABSTRACT OF THE DISCLOSURE

The release of therapeutically active agents from controlled release bases is extended by using a combination of a higher aliphatic alcohol and an acrylic resin as the base material.

Description

~2~ Ei33 BACKGROUND OF THE INVENTION

It is known in the pharmaceutical art to prepare compo-sitions which provide for slow release of pharmacologically active substances contained in said compositions after oral administration to humans and animals. Such slow release compo-sition~ are used to delay absorption of a medicament until it has reached certain portions of the alimentary tract. Such controlled release of a medicament in the alimentary tract further maintains a desired concentration of said medicament in the blood stream for a longer duration than ~ould occur if conventional rapid release dosage forms are administered.
Slow release ~ormulations known in the art include specially coated pellets, coated tablets and capsule~ wherein the slow release o~ the active medicament is brouyht ahou~
through selective breakdown of the coating of the prepara~ion or through compounding with a ~pecial matrix to affect the release of a drug. Some slow release fo~mulations provide for related sequential release of a single dose of an active compound at predetermined periods after administration.
It is the intent of all slow release preparations to provide a longer period of pharmacologic response after the administration of the drug and is ordinarily exprienced after the administration of the rapid release do~age fonms. Such longer periods o~ response provides for many inherent thera~
peutic benefits that are not achieved with corresponding shor~ acting, immediate release preparations. ~hus, therapy may be continued wi~hout interrputing the sleep of the patient, which is of special importance when tre~ting an epileptic patient ~o preven~ nocturnal seizure~, or ~or those patient~
who experience migraine h~adaches o~ awakening, a~ well as ~or 3~

the debilitated patient for whom uninterrupted sleep is essenti~l.
Another critical role for extending acting medications is in therapy of cardiovascular diseases whereby optimal peak blood levels of a medicament must be maintained at ~he steady state level to achieve the de~ired therapeutic effect. Unless conventional rapid acting drug therapy is carefully administered at frequent intervals to maintain effective steady state blood levels of the drug, peaks and valleys in the blood level of the active drug occurs because o~ the rapid absorption, systemic excretion of the compound and through metabolic inactivation, thereby producing special problems in maintenance therapy of the patient. A further general advantage of longer acting drug preparations is improved patient complianc~ resulting from the avoidance of missed doses through patient forgetful-ness .
The prior art teaching of ~he preparation and use ofcompositions providing the ~low release of an active compound from a carrier is basically concerned with the release of the active substance into the phy~iologic 1uid o~ the alimentary tract. ~owever, it is generally recognize-l that the mere presence of an active substance in the gastrointestinal fluids does not, by itself~ insure bioavailability. Bioavailability, in a more meaningful sense, is the degree, or amount, to which a drug substance is absorbed to be available to a target tissue site after administration of a unit dosage form.
To be absorbed, and ac~ive drug substance must be in solution. The time required ~or a given proport~o~ of an active druy substance contained in unit dosage form to enter into solution in appropriate physiologic fluids is known as the dissolution. The dissolution time ~ an activ~ substance from a unit dosage form is determi~ed a~ the proportion of the amount of active drug substance released fxom a unit dosage form over a specified time ba~e by a test method conducted under standardized conditions. The physiologic fluids of the gastrointestinal tract are the media for determining dis-solution time~ The present state of the art recognizes many satisfactory test procedures to measure dissolution time fox pharmaceutical compositions, and these test procedures are described in o.ficial compendia world wide.
Although there are many diverse factors which influence the dissolution of a drug substance from its carrier, the dis-solution time determined for a pharmacologically active subs-tance from the specific composition is relatively constant and reproducible. Among the different factors affecting the dis-solution time are the surface area of the drug substance pre~
sented to the dissolution solvent medium, the pH of the solu~ion, the solubility of the suhstance in the specific solvent medium, and the driving force~ o~ the saturation concentration of dis-solved material~ in the solvent medium. Thus~ the dissolution concentration o~ an active drug sub~tance is dynamically modified in its steady state as components are removed ~rom the dissolution medium through absorption across the tissue site. Und~r physio-logic conditions, the saturation level of the dissolved materials is replenished from the dosage form reserve ~o mai~tain a rela-tively uniform and ~onstant dissolu~ion concen~ration in the solvent medium providing for a ~teady state absorption~ s The transport across a tissue ab~orption site of the gastrointestinal txact is influenced by the Donnan osmotic equilibrium forces on both sides of the membrane since the direction of the driving force is ~he differen~e between the concentrations of activ~ sub~tance on either sid~ of the mem~

~3-3~

brane, i.e. the amount dissolved in the gastrointestinal fluids and the amount present in the blood. Since the blood levels are constantly being modified by dilution, circulatory changes, tissue storage, metabolic conversion and systemic excretion, the flow of active m~terials is directed from the gastroi~testinal tract into th~ blood stream.
Notwithstanding the diver~e factors influencing both dissolution and ~bsorption of a drub substance a strong corre-lation has been established between the in-vitro dissolution time determined for a dosage form and the in-vivo bioavailabi-lity. This correlation is so firmly established in the art that dissolution time has become generally descriptive of bioavailability potential ~or the ac~ive component of the particular unit dosage composition. In view o this relation-ship, it i5 clear that the dissolution time determined for a composition is one of the important fundamental characteristics for consideration when evaluating ~low release compositions.
Slow release pharamceutical composi~ion~ have generally been prepared wi~h the su~tained release matrix comprising hydroxyalkyl cellulo~e components and higher allphatic alcohol~
as described in U.S. Patent No. 4,235,870. While ~uch sustalned release matrix composition~ have constituted a definite advance in the art, i~provments in these compositions have been sought~
and improvmen~s are particularly required where the actlve pharmaceu~ical material is highly water solubleO

SU~MARY OF THE INVENTION

It is accordingly a primary object o~ the present in-vention to provide or new sustained release bases which extend the time of release of active medicament.~ incorpora~ed therein.

~ ~3~

It is anothex ob~ect of the present invention to provide new sustained release bases for pharmaceutical compositions which provide extended release time for active medicaments, and which are particularly us~ful where the active medicament is highlv water soluble.
It is yet another object of the present invention to provide sustained release base compositions which are useful for all types of pharmaceutically active ingredients and which can extend the time of release of all such ingredients.
Other objects and advantages of the present invention will be apparent from the further reading of the specification and of the appended claims.
With the above and other objects in view, the present invention mainly comprises composi*ions for controlled slow release of therapeutically active ingredients over a prede~er-mined or a specified period of time; comprising as the base composition a combination of a high~r aliphatic alcohol and an acrylic resin. Base compositions prepared from such higher aliphatic alcohols and acrylic resins provide ~ustained release of therapeutically active inqredients over a period of time ~rom ~ive hours and for as much as 24 hour~ after administration, generally oral administration, in humans or animals.
The bases o~ the prese~t in~ention are prepaxed from any pharmaceutically acceptable hiqher aliphatic alcohol/ the most preferred being fat~y alcohol~ o 10-18 carbon atoms, par~icular-ly stearyl alcohol, ce~yl alcohol, cetostearyl alcohol, lauryl alcohol, myristyl alcohol and mixture~ thereo~.

Any acrylic polymer which is phaxmaceutically acceptable can be used for ~he purposes of the presen~ invention. The acrylic polymers may be ca~ionictanionic or non~ionic polymers and may be acrylates, methacrylate~, formed of methacxylic acid 3~
or methacrylic acid esters. These polymers can be synthesized, as indicated above, to be cationic, anionic or non-ionic, which then renders the polymers that would be pH dependent and con-sequently soluble in, or resIstant to solutions over a wide range in pH. The most available of the acrylic polymers or the purposes of the present invention are ~hose that are marketed under the trade-~;u~ "~U~AGITi' and areavailable from Rohm Pharma. GmbM, Weiterstat, West Germany.
In preparing tablets or the like fxom the bases of the present invention, other excipients may be used, these being typically inert auxillary materials used in the art of tableting or capsule filling, and can include, for example, binders, such as polyvinyl pyrroldine, fillers, such as lactose, disintegrants, such as corn starch, and lubricants such as magnesium stearate.
In preparing the ma~rices o~ the presen~ invention, the two basic materials, namely the higher aliphatic alcohol and the acrylic resin, are combined together using a wet ~aqueous or ~rganic) granulation technique of at least one step, to form a uniform granulate together with any of the other excipient~
that are required ~or the table~ing or ~he capsule filling~ One or more therapeutic agents can be co~bined during the process of preparing the g~anulate, or mixed with the granulate after it is prepared.
The granulation is generally prepared ~sing the "wet"
granulating method, that is, most of the excipients with ~or without) the therapeu~ic agent or agen~ are combined together with a granulating ~luid until a moist granular mass is obtained.
The mass i5 then dried until only trace amounts of fluid remain in the granulate as residual mois~ur~. The granulate i5 then sized using a suitable screening device, which then provides a 10wable powder which can then be filled in~o cap3ule~ or com-~ 3 ~

pressed into mat.rix tablets or caplet3. It has u~expetedlybeen found that the combination of the higher aliphatic alcohol and the acrylic polymer ha~ a synergistic action with respect to delay ng the release of the therapeutically active ingredient. Thi~ phenomenon is of particular advantage when the active material is highly water soluble.
It has been observed that when desiring to control the release of some highly water soluble pharmacologically active ingredients, fox example oxycodone, rom conventional control-led release tablet matrices, a delay or gxadual release of such material can be di~icult to achieve. However, when such highly water soluble pharmacologically active material such as oxycodone is incorporated into the matrix system of the present invention, a controlled release of the material is clearly observable. The method usedto measure the control of release is the dissolution technique as descrihed in USP XXI.
In the composition of hiqher aliphatic alcohol and acrylic resin ~or controlled release bases in accordance with the present invention, the amount of acrylic resin is prefera~ly between 10-60~ (based on the total oE acrylic resin and aliphakic alcohol), more preferably 15-40%, and most preferably about 20-35%. All percentages are by weight.
It ha~ been found tha~ whe~ using ~he acrylic resins in combination with ~he higher alipha~ic alcohol, ~he preferred acrylic resin being those sold under the trade name ~udragitt and preferably the Eudr~git RL, RS, S, E30D, and L30D, there was unexpectedly a potentiation o~ the control of the dxug relea~e properties for the flow and controlled release of medicaments. This potentiation of action i5 particulax apparent in the case of the use of a highly water soluble therapeu~ic agent.

~29~

Using the combination o~ ~he aliphatic alcohol and acrylic resi.n as the base for therapeutic agents results in optimum control of drug release, utilizing the m~trix base of the present inv~ntion in a range o~ 20-40% by weight of the total weight of the selected dosage unit, and a delay in retardation of generally 5-12 hours, and up to 24 hours and be achieved. ~he lower part of the range of amount of base generally exhibits a release rate of 5 hours, and as the weight percentage of the controlled release base increases, the delay of drug release also increase~

DESCRIPTION OF PR~FERRED E~BODIMENTS
.

The following examples are give~ to further illustrate the present invent1on. The scope of the i~vention is not, however, meant to be limited to the specific details of the examples.

~ he bronchodilator drug, Aminophylline, ~which is the ethylene diamine salt of theophylline) wa~ tested in the slow release system o~ the invention.
It was desired to prepare a controlled release Aminophylline tablet containing 225 mg active ingredient.
The following three tablets demonstra~e the prin-ciples of the invention, the applicability and the advan~ages for pharmaceutical use.

3LX~G~;33 INGREDIENT FORMUl~TIONFO~MULATION FORMULATION
~A) ~B~ ~C) Aminophy 11 ine 2 2 5 . Omg2 Z 5 . Omg 115 . Omg P.V.P. 3.4mg 3.4mg3.4mg Eudragit RS ~- 10 . 0mg20 . Omg Acetos~e/Isoproplyl alcohol q . s .q. 5 q. S ~
Cetostearyl Alcohol 86 . 6mg76 . 6mg66 . 6mg Magnesium Stearate 2.4mg 2.4mg2.4mg Talc ~ 6.0mg6.0mq 323.4mg323~4mg323.4mg The tablets were prepared according to the following method:
The aminophy~line and P.V.P. were intimately mixed in a suitable mixing apparatus. The Eudragit RS ~in the case of tablets B a~d C) was dissolved in the acetone/isopropyl alcohol ~50:$0 ratio) which was used a~ the granulating ~luid.
Whilst the powders were mixing, the yranulating fluid was incorporated into the mixing powders until a moist granular mass wa~ obtained. This was then dxied and af~er drying screened throu~h a 12 mesh screen, The re~uirPd qua~ty of cetostearyl) alcohol was melted (at approxO 60-70) and using suitabl~ mixing appa~atus, then incorporated into ~he warm granular mass. After cooling, th~ granulate was screened again through a 12 mesh screen. The lubricants (talc~ magnesium stearate) were then mixed into the granulate.
- The tablet~ were compressed on a suitable tabletting machine using round biconvex tooling o~ 12/3~" in diameter.

9- .

~2~6~ 3 Dissolution results, using USP paddle 100 rpm~ in simulated gastric fluid ~or the irst hour, and thereater in simulated intestinal fluid were as follows:

% AMINOP YLLINE DISSOLVED

HOURFORMI~LATIONFOR~UI~TION FOR~qULATION
(A) [B) (C) 19 . 1% 2~) ~ 1% 19 . ~
277 . 5% 47 ~ 09~ 4a . 2%
3t 00 . 0% 67 . 2% 55 . 0%
4 84.0% 67.7%
6 100 . t)9ci 82 . 0~
8 93 . 096 9 100 . 0%

From the above dissolution results, it can be seen that when approximately 15% (10mg/tablet) o the cetostearyl alcohol was replaced with the acryli~ resin there was an 2xtension oP
the time o release o~ 100% o~ the ~minophylline ~rom three hour~ t~ six hours, and when the percentage replacement with acrylic resin was increased from 15~ to 30~ (that is 20 mg per tablet), there was a fur~her extension of 100% Aminophylline released over a nine hour period.

EXAMP~E II
The usefulness of ~he invention was furthex demonstrated by the prepareation of a controlled rQlease table~ of th~ narcotic analgesic, oxycodone.
It was dQsired to produc~ an oxycodon~ controlled release tablet which~would ~how a contxoll~d gradual releas~ o~ actlve ~q3~ 3 material over an approximate 9 to 10 hour period. The ~ollowing tablets were prepared.

Mg!tablet Inqred _nt Formulation A Formulation B

Oxycodone 9.2mg g.2mg Lactose 200.0mg 200.Omg Eudragit E30D (Solids) ~ mg Water q.s. --Stearyl alcohcl 61.2mg 50.Omg Stearic acid 5.3my 5.3mg Talc 5.3m~ 5.3m~

281.~mg 281.0mg These ~ablets were prepared according to the following method:

The oxycodone and lactose were intimately mixed ln a suitable mix~r. A granulation was then prepared by inaorporating the granulating fluid into the mixing pow~ers. In th~ case o~
table~ A, the granulating fluid was water. In the case o~
tablet B, ~he granulating ~luid was ~he acrylic suspension "Eudragit E30D", which is a 30~ aqueous sllspension of the acrylic resin, and the quantity of suspension used was the quantity equiYalen~ to 11.2mg/ tablet of solîd resin substance.
The granulate was then dried and pa~sed through a 12 mesh screen. The stearyl alcohol was mel t~d and . incoxporated into the warm granules using a suitable mixer. After cooling, the granules were passed through a 12 mesh screen. The granules were lubricat~d by mixing in the talc and steaxyl alcohol.
Tablets were t~en comp~essed on a ~uitable tabletking machine u3ing round biconYex tooling ~0/32" i~ diameter.

Dissolution results, using U.S.P. paddle, 100 r.p.m.~ in simulated gas~xic fluid for the first hour, and thereafter in simulated intestinal fluid, were as follows:

% OXYCODONE DISSOLVÆD

HOUR TAB~T A TABLET B

1 43.~ 16.

2 ~3.% 51.

3 91.~ 64.%

4 97.% 70.~
100.~ 76,%
6 78.%
8 96.~
9 100 . %

h~hen comparing the dissolution results of tablets A and B, it was observed that when approximately 20% (11.2my/tablet) of the cetostearyl alcohol wa~ replaced with Eudragit E 30D
(as solids in the ~inal ~ormulation), there was a potentiation o~ the co~trol o~ the release ~f the oxycodone ~rom the tablet formulation, Erom 100~ released ln five hour~ to a 100% release in nine hours.
EX~MPL~ III
I was desired to pr~pare a ælow release preparation of the beta-adrenergic blooking agent ~propranolol", to have a 100~ in gradual relea~e o~ the activ~ drug ov~r a nine hour period. Tv demon~trate the e~ectiveness of the invention the following tablet formulations (using the production method cited in example I abov~) wer~ prepared~

' ~L~

INGREDIENT FORMUh~TION A FORMULATION B

Propranolsl 30.0 30.0 Lactose 91.S 91.5 Eudgragit S -- 8~0 Granulating fluid (acetone/ q.s. q.s.
IPA/H20) Cetostearyl alcohol 24.0 16.0 Talc 3.0 3.0 ~agnesium Stearate . 1.5 1.5 150.0mg 150.Omg These tablets were compressed using round biconvex tooling of 9~32" in diameter.
The tablets were then tested ~or dissolu~ion using the USP ba~iket, 100 r.p.m., in simulated ~astric fluid ~or the first hour, and thereafter uslng simulated i~testinal fluid.
The results for ~he dissolu~ion wer~ as fsllows:

HOUR ~ PROPRANOLOL DISSOLVED

F~RMULATION A FORMULATION B

1 46.4 36.4 ~ 7~.4~ $5.8 3 ~4.5 67.7 '.
4 g4.4 7~3 100.0 8~.3 6 -- 90.~
8 -- g6.0 g __ 100 . O

6~

Thus we can ohserve that by substituting 33% of the cetostearyl alcohol in formula A with the acrylic resin, a potentiation of controlled release of the Propranolol is seen.
There is a further delay and extension of the dissolution time by 4 hours, to 100% release over a nine hour period.

EXAMPLE IV
The narcotis drug Morphine is very effective for pain relief, and in the care of terminal cancer, a controlled re-lease tablet, releasing the morphine slowly over many hours is particularly suitable. The followlng two tablets demonstrate the principles of the invention, and applicabili~y o the in-corporation of morphine into such a tablet allowing a cont.rolled release of active drug over many hours.

INGREDIENT FORMUL~TION A PORMUL~TION

Morphine Sulphate 30.0mg 30.0mg Lactose 79.5mg 79.5mg Eudragit ~L -- 12.Omg ~cetone/Isopropylalcohol q.s. q.s.
Stearyl Alcohol 36.Omg 24.Omg Talc 3.Omg 3.Omg Magnesium Steareate ~ m~

lSO.Omg 150.Omg The tablets were prepared according to the method referred to in Example I.

~14-This dissolution of the tablets ~USP method is described in the previous examples) were as follows:

% MORPHINE DISSO:C.VED

HOUR FORMtJLATI0~7 A FORMULATION B

31.8% 35.7%
2 48 ~ 9% 49 . 3%
3 62.6% 5s~9%
4 72 . 5% ~il . 4%
6 ~t4.3% 66.5%
8 10~ . 0% 72 . 2%
8 :2 . 8 %
1 0 0 . O 6 We can thus see that when 33% of the cetostearyl alcohol is replaced by the acrylic resin that we have an ex~.ens~on o~
dissolution time ~rom 100% drug relea~e in eiyht hou.r~ to eighteen hours. This extended 910W release o mvrphine would thus make this ~ablet even ~uitable ~or a once a day admini~-tration.
While the in~en~ion has been illustra~ed with respect to particular formulations of higher aliphatic alcohol and acrylic resin:, and with respect~to par~icular ~eEapeu~ic agents, it is apparent that variations and modification~
thereof can ~e made without departing from the spurt or ~cope o~ the invention. Such modifications are meant to be compre-hended within the ~cope and equiva~ence of the appended claims.

Claims

1. Extended action controlled release pharmaceutical composition for oral administration, comprising a pharmaceutically effective amount of a pharmaceutically active agent distributed in a controlled release core or matrix comprising a higher aliphatic alcohol of 10-18 carbon atoms and a pharmaceutically acceptable acrylic resin, said acrylic resin being present in an amount of about 10-60% by weight of the weight of said higher aliphatic alcohol plus the said acrylic resin.

2. Pharmaceutical composition according to claim 1 wherein said acrylic resin is an amount of about 15-40% by weight.

3. Pharmaceutical composition according to claim 1 wherein said acrylic resin is in an amount of about 20-35% by weight.

4. Pharmaceutical composition according to claim 1 wherein said core or matrix also includes a binder in an amount sufficient to bind said composition.

5. Pharmaceutical composition according to claim 4 wherein said core or matrix also includes a filler.

6. Pharmaceutical composition according to claim 5 wherein said core or matrix also includes a disintegrant in a disintegrant efffective amount.

7. Pharmaceutical composition according to claim 6 wherein said core or matrix also includes a lubricant.

8. Pharmaceutical composition according to claim 1 wherein said core or matrix constitutes about 20-40% by weight of said composition.

9. Pharmaceutical composition according to claim 1 wherein said pharmaceutically active agent is highly water soluble.

10. Pharmaceutical composition according to claim 1 wherein said pharmaceutical agent is amitryptaline, atropine, chlorpheniramine, chlorpromizine, codeine, dexbrompheniramine, diphenylhydramine, doxilamine, ephedrine, hyoscyamine, morphine, oxycodone, papavarine, phenylpropanolamine, propranolol, quini-dine, scoplamine, theophylline or thioridazine.

11. Core or matrix for controlled release pharmaceu-tical compositions for oral administration and being adapted for distribution therein of a pharmaceutically active agent, said core or matrix comprising a higher aliphatic alcohol of 10-18 carbon atoms and a pharmaceutically acceptable acrylic resin, said acrylic resin being present in an amount of about 10-60%
by weight of the weight of said higher aliphatic alcohol and said acrylic resin.

12. Core or matrix according to claim 11 wherein the amount of said acrylic resin is about 15-40% by weight.

13. Core or matrix according to claim 11 wherein the amount of said acrylic resin is about 20-35% by weight.

14. Pharmaceutical composition according to claim 1 and being in the form of a tablet.

15. Pharmaceutical composition according to claim 1 and being in the form of a caplet.

16. Pharmaceutical composition according to claim 1 and being in capsule form.