CA1269669A

CA1269669A - Phosphoric diesters

Info

Publication number: CA1269669A
Application number: CA000531029A
Authority: CA
Inventors: Kazumi Ogata; Itaru Yamamoto
Original assignee: Senju Pharmaceutical Co Ltd
Current assignee: Senju Pharmaceutical Co Ltd
Priority date: 1986-03-04
Filing date: 1987-03-03
Publication date: 1990-05-29
Anticipated expiration: 2007-05-29
Also published as: ES2051735T3; EP0236120A2; JPS62205091A; US4914197A; DE3781177T2; EP0236120B1; DE3781177D1; JPH0523274B2; EP0236120A3

Abstract

Abstract of the disclosure:

There is disclosed a novel phosphoric diesters of general formula:

Description

The present :invention relates to novel phosplloric d.iesters and salts thereof, whicll are of use as, for example, antiinElalllmatory ayents, a metl-lod EOK production thereof, and pharmaceutical compos.itions contai.rlilly said eompounds.
~ variety of an-tiinflammatory agents are known and it is aeknowledged that steroidal antlinflamlnatory agents are the most eEfeetive oE al].. Ilowever, steroidal antiinElammatory agents have gtrong side effects and, thereEore, present with various diff:iculties in clinical applieation. Aeeordingly; nonsteroidal antiinflammatory agents whicll differ from steroidal ayents in the mechanism of aetion have been developed and put to use but there llas not been found an eEEeetive nonsteroidal clrug whieh is fully satisfaetory in all respeets.
~ , y and ~-toeopherols are known to be eompounds having vitamin E activity. Ascorbie aeid is known to be a medieina]. substanee ~aving anti-seurvy aetivity and also an antioxidant for food and so on.

The dies-ter of phosphorie aeid with L-ascorbie aeid and c~-toeopherol, WiliCil iS strueturally similar to -the eompouncl àeeording to the present inverltion, is a ]cnown eompound but it is only knowrl to be a prophylaetle and therapeutie agent Eor eataraet and menopausal syndrome (USP No. 4,564,686).

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- :, `' ~ ' ' ' The present inventors synthesi~.ed a variety of compounds and conducted a screening of new and highly effective nons-teroiclal antiinflammatory substances. As a result, the inventors found that a eompound consistiny of aseorbie aeid and ~, y or ~-~oeopherol as bound -together in tl1e form of phosphorie diester was suited to the purpose. Tl-lus, the present invention provides a novel eompound having antlinflammatoxy aetivity, a me-thod of produeing the same, and a pharmaeeutieal eomposition eontaining said eompound.
.....
The compound according to the present invention is a novel diester of phosphorie aeid with ascorbie acid and ~, y or ~--toeopherol and has the ehemical structure represented by the following general forrnula [I]:

' c}l { C--O--~ O ~ C ~12 C ~12 ( 112 C 11 C l l 1 ~1 CH-OH
I [I]
I1o-H2C

wherein ~l and R2 are th~e same or dlEferent and eaeh~means a methyl groap or a hydrogen atom, provided I that at leas~t one of Rl and R2 is a hydrocJel1 atom, or a salt thereof.
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One aspect oE the present invention is directed to a phosphoric diester of general formula [IJ or a salt thereof.
Another aspect of the present invention is direct-ed to a method of producing a phosphoric cliester of general formula [I] or a salt thereof, which cornprises reacting ~, y, or ~-tocopherol with a halophosphorylat-ing agent, reacting the resulting reaction product with ascorbic acid having hydroxy-protecting groups in 5- and 6-positions, and removing said protecting groups.

In producing the compound accoxding to the present invention, ~, ~ or ~-tocopherol is firs-t reacted wi-th a halophosphorylating agent. While -the halophosphoxylating agent may be any compound tllat can halophosphorylate -the hydroxyl gx-oup o e ~, y or ~-tocopherol, phosphorus oxyhalides such as phosphorus oxytrichloride, phosphorus oxytribromide, etc can be employed with particular advantage. ~ ~
The reaction proceeds with advantage in an inert solvent such as benzene, toluene or the like and in the presence of~an acid acceptor. As the acid accep-tor, an organic~amine~ 5uch as pyridine, triethylamine, etc. may be employed. ~
When phosphorus o~ytrichlorifle is used as the ~ha1ophosphorylating agent, the reaction may be written as follows.
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Cll 3 Cli ( cll2cll2cll2 lll ) 3 C113 R

C~l 112\~ 3 C113 Cl Rl [ II ]

wherein R1 and R2 are the same or differnt and each means a methyl group or a hydrogen atom, provided that at least one of R1 and R2 is a hydrogen atom.
The ~, y or ~-tocopherol employed as a reactant may be whichever of the DL-compound and the D-compound.
hus ~ the reaction proceeds in the same manner and the yield is the same.
In -the present inventlon, the reaction product -thus obtained (formula [II]) is then reacted with ascorbic acid having hydroxy-protecting groups in 5-and 6-positions. For -this reaction, the above-mentioned compound lII] may be isola~ted from -the reaction mixture or, if desired, the reac-tion mix~ture may be directly subjected to reaction with ascorb:lc acid. ~ith regard to protec-tive groups for hydroxyl groups in 5- and 6-positions oE ascorbic acid, various groups are lcnown in the field of ascorbic acid chemistry and one selected .

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from among such groups may be emp:loyed for tl~e purposes of the invention. ~mong such protective yroups are isopropy:Lidene group, acyl groups such as acetyl, and so on. Most generally, an isopropylidene group is employed. ~'he reaction proceeds readily in an appropriate inert organic solven-t. As the solvent, it is generally preEerable -to employ a nonpolar solvent such as tetra--hydrofuran, acetonitrile or -the like but any other solvent that does not interfere wi-th the reaction may likewise be employed. The reac-tion proceeds readily in the presence of an acia acceptor. The preferred acid acceptor is a tertiary amine such as pyridine, triethyl~
amine and so on. The reaction for elirnination of the protective group is conducted under mild conditions.
For example, by making the reaction mixture acidic, the protec-tive group can be easily eliminated. For this acidification, a suitable inorganic acid such as hydrochloric acid, phosphorlc acid, sulfuric acid, etc.
or an organic acid such as ace-tic acid, citric acid, etc. may be employed.
The above procedure gives the compound [I] according to the present invention.
In terms of crystallinity, the compound according to the present invention is preferably in the salt form rather than in the free acid form. ~mong the salts, the sodium salt and potassium salt, Eor instance, are readily soluble in water but -the calcium salt is insoluble. For convertion of the fxee acid to a salt, ~neutralization is the easies-t and generally the most .

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suitable procedure.
The compound accordiny to the present invention is useful as a nonsteroidal antiinflammatory agent.
The compound is stable at room temperature and can be formulated in the form of free acid or a pharma-cologically acceptable salt into suitable medicinal composition by the established pharmaceutical proce-dures. The term "composition" as used herein means any and all of sterile injectable products, ophthalmic products, tablets, capsules, ointments, creams, poultices and other preparations.
While the amount of compound [I] in such a pharma-ceutical composition depends on dosage form, symptom, and so on, the compound is incorporated generally in a proportion of about 0.005 to 30 w/v percent and preferably about 0.01 to 10 w/v percent. Taking an injection as an example, an aqueous solution containing abaut 0.01 to 0.1 w/v percent of the compound may be provided. In the case of an olntment, it may contain about 1 to 10 wlw percent of the compound. As to peroral dosage forms, about 100 to 1000 mg per day per adult may be formulated.
The antlinflammatory compositions according to the present invention may contain various other agents and substances. Such agen-ts or substances include pre-servatives, excipien-tsj nonionic surfactants, and so on and unless the object of the present invention are not interferred with, other suitable drugs, colorants, , etc.~ ma~y also be incorporated.

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The phosphoric diester of ascorbic acid and ~, Y
or ~-tocopherol according to the present invention can be used with advantage as an ingredient in pharma-ceutical preparations and cosmetic products. If the phosphoric ester bonds are cleaved by phosphatase or the like in vivo, the cornpound yields vitamin C and the corresponding tocopherol active substance so that no toxic metabolites are produced, thus presen-ting no safety problem.
Referring to the drawing, Figure 1 shows the infra-red absorption spec-trum of L-ascorbyl D-~-tocopherol phosphate sodium.
The following examples and experimental examples are further illustrative of the present invention.

Example 1 L-ascorbyl DL-~-tocopherol phosphate ~[general formula (1) wherein R1=methyl, R2=H]
sodium In 30 ml~of benzene was dissolved 3 g of phosphorus oxytrichloride, and a mixed solution of 4.2 g (0.01 mole) of DL-~-tocopherol and 4~g of pyridine in 20 ml of benzene was added dropwise with stirring. After completion of dropwise addition, the mixture was further stirred fo~r 3 hours and the precipitated pyridine hydro-chloride was filtered off. The filtrate was then con-centrated~under reduced pressure and 20 ml of benzene :
was added~to the oily residue.

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On the other hand, 2.6 g (0.012 rnole) of 5,6-iso propylidene-protected ascorbic acid prepared hy acetonization of L-ascorbic acid and 2 g of pyridine were dissolved in 60 ml oE tetrahydrofuran (~rl]F~ and -the above benzene solution was added dropwise with stirring. After completion of dropwise addition, the mixture was stirred for about 1 hour and -the precipitated pyridine hydrochloride was fil-tered off. The Eiltrate was concentrated under reduced pressure to remove the solvent. The resu~ting oil was dissolved in 15 ml of ethyl alcohol and after addition of 75 ml of lN-hydrochloric acid, the solu-tion was refluxed for about 15 minutes.
After cooling, the reaction mixture was ex-trac-ted with ethyl acetate and dried over anhydrous sodium sulfate.
The ethyl acetat.e was then dis-tilled off to give crude free acid as a residue.
This crude free acid was dissolved in about 100 ml of ethyL alcohol and, then, a solu-tion of potassium hydroxide in ethyl alcohol was gradually added in drople-ts until the pH of the solution became neutral, whereupon slightly brownish whlte crystals separated out. The crys-tals were collec-ted by filtration to give the potassium s~lt. :
The above po-tassi.um salt was dissolved in 100 ml of water and the solution was acidified with hydrochloric acid and extracted wi-th ethyl acetate.

The extract was dried over anhydrous Na2SO~ and the ethyl acetate was distilled off to give -the free acid :
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g as a light yellow amorphous solid. This 501id was dissolved in 80 ml of ethyl alcohol and a solution of sodium hydroxide in the alcohol was added dropwise until the solution became neu-tral, whereupon whi-te crystals separated out.
The crystals were collected by filtration and recrystallized from tetrahydrofuran-ethyl alcohol to give 3.2 g (45.0%) of whi-te powdery crystals. The UV
spectrum of this product shows absorptions around 200, 220 and 257 nm (in water).
Melting point: Carbonization begins gradually around 210C.
Elemental analysis: (for C3~H53OlOPNa2'H2O) Calcd. C, 56.97% H, 7.73%
Found C, 56.77% H, 7.75 Example 2 L-Ascorbyl DL-y-tocopheryl phosphate Igeneral formula (1) wherein Rl=H; R2=methyl]
sodium s In the same manner as Example 1, the above compound was obtained as white powdery crys-tals in a yield of 55~.
m.p.: Carbonization begins gradually around ~ 200C.
Elemental analysis: for C3~H53OlOPNa2'H2O
Calcd, C, 56.97~ H, 7.73%
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Found C, 56.88% ~-l, 7.65 Example 3 L-~scorbyl D-~-tocopheryl phosphate [general formula (1) wherein E~l and R2 each =
H] sodium In the same manner as Example 1, the above compound has synthesized as white powdery crystals in a yield of 48%.
[~]D + 45.8 (C=l.0, H2O) m.p.: Carbonization begins gradually around 210~C.
Elemental analysis: for C33H51OlOPNa2-H2O
Calcd. C, 56.40% H, 7.60%
Found C, 56.60% Ht 7.41~
The infrared absorption spectrum (KBr) of this product is shown in Fig. 1.
Experlmental Example 1 (Topical antiinflammatory effect) The antlinflammatory effect of the compound according to the present invention was investigated in the anterior chamber paracentesis inflammation model of the rabbits eye.
Method: Using female white rabbits, a 0.1%
~ ophthalmic solution of L-ascorbyl tocopheryl phosphate sodium and, as a control, physiolo~ical saline were :

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instilled into the bilateral eyes of rabbits in volumes of 10 ~1 each at 2, l and 0~5 hour before peracentesis and using a 27-gauge needle about 200 ~l of anterior chamber aqueous humor was collected frorn each eye (primary aqueous humor). I'hen, after an interval of 1.5 hours, the aqueous ~lumor was collected again in the same manner (secondary aqueous humor). The protein con-tent of each aqueous sample was determined by the method oE Lowry and the increases in the amount of protein (pro-tein content of secondary aqueous humor - protein content of primary aqueous humor) in the respective groups were compared to evaluate the antiinf].ammatory effect of each test substance.
Results: The increase in the amount of protein in secondary aqueous humor in each group is shown in Table 1.
Compared with the control group, the compound according to the present invention showed a signlficant antiinflam-matory;effect.

~ Tahle 1 Group~ Increase in ~ Inhibition Numher of ~ protein eyes Control 25.5 - 10 ~B-EPC~ ~ 16.0 37.3 6 y-EPC ; 16.2 36.5 6 ~-EPC 15.3 40.0 DEX 20.8 1~.4 6 .
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~-EPC: L-a~corbyl DL-~--tocopheryl phosphate sodium y-EPC: L-ascorbyl DL-~-tocopheryl phosphate sodium ~-EPC: L ascorbyl D-~-tocopheryl phosphate sodium DEX: 0.l% Dexamethasone ophthalmic solution Experimental Exampl (Inhibitory effect on ultraviole-t-induced erythema) Method: The back hairs of Hartléy guinea pigs were clipped with an electric clipper and shaved with an electric razor. Then, a cloth with two holes ll mm in diameter and 4 cm apart was applied to the back for positioning and a l (w/v) ~ aqueous solution of ~-EPC
(adjusted -to pH 6.0) and, as control, water were applied 3 times in l00 ~l portions each at l-hour intèrvals around the sites of said holes over an area 4 cm in diameter. One hour after the final application, said cloth with small holes was applied again and the exposed skin~areas was irradiated with ultraviolet rays at 1700 luxes for 360 seconds. Then, after l and 2 hours, respectively, the back was grossly examined for erythema.
~ No erythema Slight erythema :. :

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Table 2 G After 1 hour After 2 hours roup Right Left Right Left

2 2 2 2 Control 32 22 2 22 0 , 1 0 ~-EPC

Result: Compared with the control group, ~-EPC
showed a significant antiinflammatory effec-t.
Preparation Example 1 Ophthalmic solution for topical application L-Ascorbyl DL-~-tocopheryl phosphate sodium 0.1 g Borlc acid 1.5 g Borax 0 3 Methyl P-hydroxybenzoate 0.026 g Propyl P-hydroxybenzoate 0.014 g Sterile pure water To make 100 ml According to the above formula, an ophthalmic solution -.

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was prepared in accordance with the established pharmaceutical procedure.
Preparation Example 2 Peroral Table-ts 5 L-Ascorbyl DL~~-tocopheryl phosphate sodium lO0 mg Lac-tose 80 mg Starch l7 mg Magnesium steara-te 3 mg Using the above formulation for 6 tablets, tablets for oral administration are prepared in accordance with the established pharmaceutical procedure. The tablets may be sugar-coated.
Preparation Example 3 Injection 15 L-Ascorbyl DL-~-tocopheryl phosphate sodium 0.02 g Glucose 5 g Distilled water for injection To make lO0 ml Using the above formula, an in~ection is prepared by the established pharmaceutical procedure for sterile products.
Pre~paration ExampIe 4 Dermato1ogical olntment for external application L~Ascorbyl DL~y-tocopheryl phosphate sodium 5.0 g ~ Glycerin l2.0 g ~Stearyl alcohol 25.0 g :: ~ : .

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Preparation Example 5 Syrup L-Ascorbyl DL~~-tocopheryl phosphate sodium 2.0 g D-Sorbitol, 70~ soln. 70 ml Methyl P-hydroxybenzoate 0.028 g Butyl P-hydroxybenzoate 0.012 g The above ingredients are dissolved in sterile pure water, adjus-ted to pH 6.0 wi-th lN-HCl, diluted to a total of 100 ml, and filtered. The filtered solu-tion is filled into a gl~ss bottle to provide a syrup.
Preparation Example 6 Cosmetic lotion L-Ascorbyl DL-R-tocopheryl phosphate potassium 1.0 g Citric acid 0.1 g Glycerln 5.0 g Ethyl alcohol 8.0 ml .:
Metbyl P-hydroxybenzoate 0.1 g ~ ~ ~

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The above ingredien-ts are d:issolved in sterile pure water, adjusted -to pH 6.0 wlth lN-sodium hydroxide, made up -to a total of l00 mlj and fil-tered. The filtered solu-tion is filled into a glass bot-tle to provide a cosmetic lotion.
Pxepara-tion Example 7 Cream L-Ascorbyl D-~-tocopheryl phosphate sodium l.0 g Stearic acid 2.0 g Stearyl alcohol 7.0 g Squalane 5.0 g Octyldodecanol 6.0 g Polyoxyethylene (15) cetyl ether 3.0 g Glycexin monostearate 2.0 g Propylene glycol 5.0 g Methyl P-hydroxybenzoate 0.2 g .~
Propyl P-hydroxybenzoate 0.l g SteriIe pure water To make 68.7 g In sterile pure water are dissolved propylene glycol and L-ascorbyl D-~-tocopheryl phosphate sodium and the~
solution is warmed to 70C. The other ingredien-ts are mixed and warmed to 70C. Then, with stirring at the same temperature, the above aqueous solution is added and the~mixture is homogeniæed well and cooled to room temperature. It is then filled into a cream container to provide a cosmetic cream.

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Claims

Claims:

1. A phosphoric diester of general formula:

wherein R1 and R2 are the same or different and each means a methyl group or a hydrogen atom, provided that at least one of R1 and R2 is a hydrogen atom, or a salt thereof.

2. A phosphoric diester or a salt thereof accord-ing to claim 1, wherein R1 is a methyl group and R2 is a hydrogen atom,

3. A phosphoric diester or a salt thereof accord-ing to claim 1, wherein R1 is a hydrogen atom and R2 is a methyl group.

4. A phosphoric diester or a salt thereof accord-ing to claim 1, wherein each of R1 and R2 is a hydrogen atom.

5. A method of producing a phosphoric diester of general formula:

wherein R1 and R2 are the same or different and each means a methyl group or a hydrogen atom, provided that at least one of R1 and R2 is a hydrogen atom, or a salt thereof, which comprises reacting .beta., .gamma. or .delta.-tcopherol with a halophosphorylating agent, reacting the resulting reaction product with ascorbic acid having hydroxyl-pro-tecting groups in 5-and 6-positions, and removing said protecting groups.

6. A method according to claim 5, wherein a phos-phoric diester having a methyl group as R1 and a hydrogen atom as R2 is produced.

7. A method according to claim 5, wherein a phos-phoric diester having a hydrogen atom as R1 and a methyl group as R2 is produced.

8. A method according to claim 5, wherein a phos-phoric diester having a hydrogen atom as each R1 and R2 is produced.

9. A method according to claim 5, wherein .beta., .gamma.
or .delta.-tocopherol is reacted with a phosphorus oxyhalide in an inert solvent in the presence of an acid acceptor, the reaction product is reacted with ascorbic acid whereof hydroxy groups at 5- and 6-positions are protected with an isopropylidene group in a nonpolar solvent in the presence of a tertiary amine, and then the isopropylidene group is removed by making the reaction mixture acidic.

10. An antiinflammatory composition which com-prises an effective amount of a compound represented by the general formula:

wherein R1 and R2 are the same or different and each means a methyl group or a hydrogen atom, provided that at least one of R1 and R2 is a hydrogen atom, or a salt thereof, and a carrier.