NO148491B - ANALOGY PROCEDURE FOR THE PREPARATION OF ANTI-INFLAMMATORALLY EFFECTIVE 21-SALICYLIC ACID AND 21-ACETYLSALICYLIC ACID ESTERS OF PREGNANCY STEROIDS - Google Patents

Description

The present invention relates to the production of new steroids with particularly high anti-inflammatory activity by topical and/or systemic administration.

The compounds produced are 21-salicylic acid esters or 21-acetylsalicylic acid esters of steroids of the pregnane series and with the general structure

where R is hydrogen or an acetyl group, X is hydrogen or fluorine, X<1> is hydrogen, fluorine or methyl, Z may be hydrogen or tf-^methyl. Compounds of the general formula I are prepared by reacting a compound of the general formula II

wherein X, X<1>' and Z have the previously stated meanings,

reacted with a suitable derivative of acetylsalicylic acid.

Typical examples of suitable acetylsalicylic acid derivatives are the corresponding acyl halides, such as the chloride, or an activated ester. The compounds according to the invention can also be prepared by reacting the compound of the general formula II with the free acetylsalicylic acid in the presence of dicyclohexylcarbodiimide.

Correspondingly good results can be obtained by converting a compound of the general formula II into the corresponding 21-mesylate which is then reacted in a solution in a polar solvent with an alkali metal salt of acetylsalicylic acid to give the desired ester. By mild alkaline hydrolysis of the thus obtained 21-acetylsalicylic acid ester under a nitrogen atmosphere and room temperature, the corresponding 21-salicylic acid ester can be obtained and isolated in the usual way.

The 21-salicylic acid ester of the desired steroid can be prepared directly by reacting the corresponding 21-mesylate in solution in a polar solvent with an alkali metal salt of salicylic acid.

The compounds are useful in the treatment of several inflammatory conditions

attacks on the mucous membrane and skin such as rectal or colonic inflammation, conjunctivitis or phlogosis in the ear and nose, dermatitis of various causes, eczema, psoriasis and allergic effects. They are also useful for the treatment of internal inflammatory attacks, especially rheumatic arthritis and allergic diseases.

For topical application, the active ingredients of structure I can be incorporated into the usual compatible carriers and additives for the preparation of pharmaceutical compositions suitable for topical administration.

Typical examples of such mixtures are ointments, lotions, creams, emulsions, drops, sprays and suppositories as are well known in pharmacy. Ointments can, for example, be prepared for both hydrophilic and hydrophobic application, and they can be prepared so that they are formed on an aqueous or non-aqueous basis.

The pharmaceutical additives suitable in these mixtures are, for example, animal fat, vegetable oils, fatty acids, poly-alkylene glycols, beeswax, polyesters and the like.

The pharmaceutical mixtures may also contain other active ingredients such as preservatives and bacteriostatic agents.

The proportion of the active steroid in the pharmaceutical mixtures depends on the particular mixture and the inflammatory attack to be cured.

Advantageously, a topical mixture will contain the active ingredient in an amount of 0.01 - 5% by weight.

These anti-inflammatory topical mixtures can be applied to the affected area a few times a day.

For systemic administration, the active ingredient can be incorporated into pharmaceutical mixtures for oral or parenteral administration. These pharmaceutical mixtures can, for example, be solid or liquid, and can be produced in pharmaceutical forms generally used in human medicine, such as tablets, capsules, granules, solutions and suspensions, as well as injectable forms.

The pharmaceutical additives which are suitable in these mixtures are, for example, talc, gum arabic, lactose, starch, magnesium stearate, polyethylene glycol and the like.

For systemic administration, the mixtures will contain the active ingredient in an amount of 0.5 - 5 mg per unit dose, and the daily dose can vary from 1 - 100 mg.

The following examples illustrate the invention.

EXAMPLE 1

9a- fluoro- prednisolone- 21- acetylsalicylate

Into a four-necked flask fitted with a stirrer, thermometer, dropping funnel and a CaCl2 tube are introduced 9a-fluoro-prednisolone (10 g) and a mixture of dry pyridine (30 ml) and dioxane (30 ml). After cooling to 5°C, introduce drop by drop. 8 g of acetylsalicyloyl chloride dissolved in 16 ml of dioxane, and the mixture is left overnight at approx. 2°C and with stirring. The suspension obtained is poured onto ice and the solid obtained is collected by filtration, washed with water and dried.

The 9a-fluoroprednisolone-21-acetylsalicylate obtained is recrystallized from ethyl acetate.

EXAMPLE 2

9 a- f luor- prednisolone- 21- salicylate

9α-Fluoro-prednisolone-21-acetylsalicylate (10 g) in 120 ml tetrahydrofuran is treated at room temperature under a stream of nitrogen with 10 ml 1M methanolic sodium hydroxide. 2 hours later, the mixture is neutralized, evaporated under vacuum, diluted with methanol and poured into water. The 9a-fluoro-prednisolone-21-salicylate obtained is recrystallized from ethyl acetate.

EXAMPLE 3

9a- fluoro- prednisolone- 21- salicylate

Preparation of the starting material 9a-fluoro-prednisolone-21-mesylate

Into a four-necked flask equipped with a stirrer, thermometer, dropping funnel and a CaCl 2 tube were introduced 10 g of 9α-fluoro-prednisolone and 20 ml of anhydrous pyridine. The solution was cooled to -5°C, and 6 ml of methanesulfochloride was added dropwise with stirring, after which the reaction mixture was stirred for a further 6 hours at approx. 0°C, after which it was poured onto crushed ice, and the resulting solid filtered off, washed with water and dried.

B- Conversion of 21-mesylate to the desired 21-salicylate.

To a suspension of 10 g of 21-mesylate in 100 ml of dimethylformamide, 15 g of sodium salicylate was added with stirring and at room temperature. The reaction mixture was heated to 100°C with stirring and kept under these conditions for a further 2 hours, after which the mixture was poured into 100 ml of cold water. The filtrate formed was filtered off, washed with water and dried.' The crude product obtained was recrystallized from acetone and 7 g of the pure product was obtained which had the following properties: m.p. 209.3°C

20

[a]D = + 152.07 (c = 1 dioxane), UV - spectrum /imax = 251 mu; El<%>cm 476'2' IR " spectrum (nujol) 3290 - 1730 - 1710 - 1670 - 1660 - 1610 - 1605 - 1580 cm"<1>.

EXAMPLE 4

6a, 9a- difluoro- 16a- methyl1- prednisolone- 21- salicylate

By following the procedure described in example 3, the 21-salicylic acid ester of 6a,9a-difluoro-16a-methyl-prednisolone (also called flumetasone) was prepared and exhibited the following properties: m.p. 242.8°C; [cl]^ 5 = + 131.33° (c = 1 dioxane), UV - spectrum Amax. 240 mU; e}% = 523.46

Biological determinations

The topical anti-inflammatory activity of 21-salicylic acid esters and 21-acetylsalicylic acid esters according to the invention was determined using the following method: a) Inhibition of cotton pellet-induced granuloma This determination was carried out according to Meier R., Schuler W. ,

Desaulles P. Experientia Volume 6, 469, 1950.

White male rats (Wistar-Morini) with a weight of 150+10 g were used. Under light ether anesthesia, a cotton pellet was introduced subcutaneously on each side of the back via a midline incision. The pellets were cut from dental cotton rolls (no. 1 Johnson & Johnson) and combined in pairs to a weight of 100 + 1 mg. Before implantation, each pellet was dipped in an aqueous suspension (1%) of carrageenan ("Viscarin carrageenan REX 7205"), dried overnight on filter paper and then heated in an autoclave at 121°C for 1 hour.

The anti-inflammatory activity of two compounds prepared according to the invention, namely 9a-fluoro-prednisolone-21-salicylate and 9a-fluoro-prednisolone-21-acetylsalicylate was compared with 9a-fluoro-prednisolone-21-acetate.

Scaled doses of the test compounds dissolved in N,N-dimethylformamide were added to each pellet in a volume of 0.2 ml. Pellets with only 0.2 ml of N,N-dimethylformamide added are used as a control. The pellets are allowed to dry for 24 hours in an oven at 60°C and before implantation each individual pellet is dipped in a 0.5%<1>ig antibiotic solution ("Combiotic Pfizer").

At the end of the experimental period (8 days after implantation), the animals are killed with CO2 asphyxia. Pellets with surrounding granuloma are removed, dried to constant weight at 60°C and weighed.

The amount exceeding 100 mg represents the weight of the granuloma and is expressed in mg/100 g body weight.

The results are indicated in the following table.

A statistical examination of the data obtained (R. Borth "Simplified Mathematics for Multiple Bioassays" Acta Endocrinol. 35, 454, 1960) indicates that 9a-fluoro-prednisolone-21-salicylate and 9a-fluoro-prednisolone-21-acetylsalicylate are respectively 12 and 22 times as active as 9a-fluoro-prednisolone-21-acetate•

b) Inhibition of carrageenin-induced rat paw edema Flumetasone salicylate was administered orally in an aqueous vehicle

containing 0.9% NaCl, 0.4% "Polysorbate 80", 0.5% CMC and 0.9% benzyl alcohol. White male rats (Wistar) weighing 150-175 g were divided into 4 groups of 10 animals in each group and the animals were fasted overnight before the start of the experiment. Immediately before the administration of flumetasone salicylate or the aqueous vehicle, each animal was administered 5 ml of water. One hour later, 0.1 ml of a 0.5%<1>ig aqueous suspension of carrageenin "Rex 7205", Marine Colloids Inc., Springfield, N.J. - USA) injected through a 2o gauge needle into the plantar aponeurosis of the right hind paw according to Winter et al. (P.S.E.B.M., 111, 544, 1962). Foot volume was measured immediately before carrageenin administration and again 3 hours later using a mercury plethysmometer. This was done by submerging the paw of the unanesthetized animal

in mercury until this reached the lateral malleolus. Increase in paw volume was calculated from the difference between the values at 0 and 3 H after injection of the phlogistic agent. The given data in the following table indicate that ED^Q for

flumetasone salicylate is 0.34 mg/kg.

The following examples illustrate topical and also systemic compositions prepared according to the invention.

CLINICAL TRIALS

General regarding topical administration

The patients were adults of both sexes. The patients who took part in this trial were diagnosed to have skin diseases which are normally considered to respond positively to steroid treatment.

The treatment agents used were:

a) Ointment containing 9a-fluoro-prednisolone-21-salicylate (FPS), and b) ointment containing 9a-fluoro-prednisolone-21-acetate (FPA).

Each treatment agent was packaged in identical coded tubes, as follows

that those who carried out the investigations did not know which agent was used. Evaluation of the treatment results was done in each case while the identity of the treatment agent remained unknown.

A covering bandage was used for each patient.

Patient 1

LET. 50 years - Housewife

Affected by a 7-year-old bilateral palmo-plantar chronic hyperkeratotic eczema.

Cycles of 3 days with application of 0.125% FPS (right foot) or 0.125% FPA (left foot) began on April 21, 1977.

After 7 days, a satisfactory reduction could be observed both with respect to erythema and hyperkeratosis on the right foot, while only a small reduction of erythema on the left foot could be observed.

After 14 days, no erythema could be seen on the right foot, and there was a further marked reduction of hyperkeratosis on this foot, while barely any improvement could be demonstrated on the left foot.

Patient 2

G. C. 55 years - Housewife

Affected by a 2-month-old bilateral palmo-plantar eczematous hyperkeratotic dermatitis.

Treatment with 0.125% FPS (right hand and foot) or 0.125% FPA (left hand and foot) began on June 23, 1977.

After 3 days, reduced itching and hyperkeratosis could be observed on both the right hand and foot, while no improvement could be demonstrated on the left hand and foot.

After 6 days, a reduction of erythema and hyperkeratosis could be observed on the right hand and foot, while only a reduction of itching and erythema could be demonstrated on the left hand and foot.

The patient was then treated with FPS on both sides until complete healing.

Patient 3

M. G. 7 4 years - housewife

Affected by long-term psoriasis with large confluent patches of psoriasis on the front surfaces of the legs.

Treatment with 0.250% FPS (right leg) or 0.250% FPA (left leg) began on June 29, 1977.

After 3 days, reduced erythema could be observed on the right leg, while no improvement could be demonstrated on the left.

After 6 days, further reduction of erythema and almost complete disappearance of desquamation could be observed on the right leg, while only a slight improvement could be detected on the left.

The patient was then treated with FPS on both legs until complete healing.

Patient 4

C. G. 29 years - Worker

affected by a 1-year-old recurrent nummular eczema on legs, more severely affected on left leg.

Daily treatment with 0.250% FPS (left leg) or 0.250% FPA (right leg) began on 12 Aug. 1977.

After 7 days, a reduction in itching and erythema could be observed on both legs.

After 14 days, a marked improvement in erythema and the disappearance of desquamation could be observed on the left leg, while erythema and desquamation could still be observed on the right leg, although to a lesser extent.

Patient 5

C. G. 46 years - Businessman

Affected by a week-old erythematous-vesicular eruption with inflammatory fluid, peeling and itching, more severe on the right forearm.

Daily treatment with 0.0625% FPS (right forearm) or 0.0625% FPA (left forearm) began on 14 Aug. 1977.

After 7 days, reduced itching and the disappearance of inflammatory fluid on both forearms could be observed. A slight reduction in scaling on the right forearm could also be observed.

After 14 days, the disappearance of itching and blisters on both forearms could be demonstrated.

Disappearance of desquamation on the right foram could be detected, while desquamation continued on the left.

Patient 6

B. G. 69 years - Retired carpenter

Affected by eczema on both hands.

Daily treatment with 0.250% FPS (right hand) or 0.250% FPA (left hand) began on 16 Sept. 1977.

After 7 days, a slight improvement could be observed on both hands with reduced itching, but peeling continued.

After 14 days, the peeling on the right hand disappeared, while only

a slight scaling reduction could be detected on the left.

Claims (1)

Analogous method for the production of compounds with anti-inflammatory activity by local or systemic administration, which compounds are 21-salicylic acid esters and 21-acetylsalicylic acid esters of steroids from pregnancy series, which compounds have the general for mel in which R is hydrogen or an acetyl group, X is hydrogen or fluorine, X' is hydrogen, fluorine or methyl, Z is hydrogen or α-methyl, characterized by reacting a compound with the general formula in which X, X<1> and Z have the meanings stated above, with an acetylsalicylic halide for the preparation of 21-acetylsalicylic acid esters and, if desired, converting the obtained 21-acetylsalicylic acid ester by mild alkaline hydrolysis at room temperature and under an inert atmosphere into the corresponding 21-salicylic acid ester, or converting a compound of the general formula II into the corresponding 21-mesylate and reacting the obtained 21-mesylate in a solution in a polar solvent with an alkali metal salt of either acetylsalicylic acid or salicylic acid.