WO1996037193A1

WO1996037193A1 - Topically applicable agents for treating and preventing alopecia

Info

Publication number: WO1996037193A1
Application number: PCT/EP1996/002195
Authority: WO
Inventors: Ralph Lipp; Jutta Riedl; Andreas Sachse; Georg Rössling
Original assignee: Schering Aktiengesellschaft
Priority date: 1995-05-22
Filing date: 1996-05-22
Publication date: 1996-11-28
Also published as: KR19990021864A; CA2222061A1; EP0827395A1; DE19519273A1; JPH11505262A; AU5819996A

Abstract

The invention relates to topically applicable agents for the treatment and prevention of alopecia characterised by a content of vitamin D analogues encapsulated in liposomes.

Description

Topical agents for the treatment and prophylaxis of alopecia

The invention relates to topically applicable agents for the treatment and prophylaxis of alopecia, which is characterized by a content of vitamin D analogs encapsulated in liposomes.

It is known that vitamin D analogues can be used to treat various forms of alopecia. For example, GB-A 2 260 903 and WO 93/00079 describe topically administrable compositions which contain vitamin D analogues in ointments, creams, gels or lotions. Since these previously known formulations, in particular if they additionally contain penetration-enhancing agents such as ethanol or propylene glycol, also have a systemic activity, they also develop undesirable side effects in addition to the desired therapeutic effect. In particular, they also influence calcium metabolism, which can lead to hypercalcemia and hypercalcuria.

The topically administrable agents according to the invention, which contain vitamin D analogs encapsulated in liposomes, are extremely effective in treating various forms of alopecia, but in contrast to the previously known agents, undesirable systemic side effects are not observed in them.

Vitamin D analogs which are suitable for the preparation of the agents according to the invention are, for example, calcitriol (lα, 25-dihydroyvitamin D3), calcifediol (25-hydroxyvitamin D3), calcipotriol (CAS-1128-00-9) and colecalciferol (Vitamin Ds) and the tacalcitol (CAS-57333-96-7). In addition, the vitamin D analogs mentioned in the abovementioned GB-A 2 260 903 and WO 93/00079 are also suitable for producing the agents according to the invention. The compounds described in WO 94/07853 are also suitable as suitable vitamin D analogs, such as, for example, the (5Z, 7E, 22E) - (1S, 3, 24R) -1, 3,24-trihydroxy-9, 10-secocholesta-5,7, 10 (19), 22-tetraen-25-carboxylic acid isopropyl ester.

The methods which are known per se to the person skilled in the art can be used to encapsulate the vitamin D analogs in liposomes. For example, these active ingredients and the liposome-forming substances can be dissolved in an organic solvent, the solution added to an aqueous phase and, if necessary, the solvent removed by distillation after homogenization. Usually 100 to 500,000 times the amount by weight of liposome-forming substance or mixture of substances based on the vitamin D analogs are used. Suitable liposome-forming substances are in particular phospholipids, such as the sphingomyeline, the plasmalogens, the phosphatidylcholines, the phosphatidylethanolamines, the phosphatidylserines, the phosphatidylinosites and the cardiolipins, or else mixtures of these lipids (Dr. Otto-Albert Neumüller: Römpps Chemie-Lexikon; Franksche Verlaghandlung, Franksche Verlaghandlung Stuttgart (DE), 9th edition, 1991, 3383f) and mixtures of these phospholipids with cholesterol and / or charge carriers, such as, for example, stearylamine, stearic acid or diacetyl phosphate.

0.5 to 10 percent by weight of phospholipid or lipid mixture, based on the aqueous phase, is usually used to prepare the liposome suspensions. Suitable mixtures can contain up to 60 percent by weight of cholesterol and up to 30 percent by weight of charge carriers. Ethanol, methanol, isopropanol, diethyl ether, acetone, chloroform and mixtures of these solvents are preferably used as solvents.

Since the lipoids are sensitive to oxidation, the process is advantageously carried out under an inert gas atmosphere, such as nitrogen or argon, and the aqueous liposome solutions obtained are stabilized by adding antioxidants, such as sodium ascorbate, tocopherol or sodium bisulfite.

Furthermore, the aqueous liposome solutions can also contain additional active ingredients, such as bactericides, preservatives and / or buffer substances.

The encapsulation of the vitamin D analogs in liposomes can be carried out under the same conditions as the previously known methods of this type (pharmacy in our time ü, 1982, 97-108; Pure Appl. Chem., 53, 1981, 2241-2254) . The encapsulation of the vitamin D analogs can take place both in multilamellar liposomes and in unilamellar liposomes.

In the process according to the invention, however, it is also possible, on the other hand, not to use solvents by distillation but by means of the known methods of transmembrane distillation (Chem. Ing. Techn. 56, 1984, 514-521; J. of Membrane Sei., 39, 1988, 45-51; DE-A 33 12 359) or pervaporation (Swiss Chem., 10, 1988, 45-51; ACS Symposium 281., 1985, 467-478; Chem. Ing. Techn., 60, 1988, 590-603).

The active substance-containing liposome suspensions prepared in this way can be diluted with water if necessary and / or thickeners, such as, for example, hydroxyethyl cellulose, methyl cellulose, Aerosil® (Herseller Degussa AG, DE), Carbopol® (BFGoodrich Chem., USA) etc. can be added to make them spreadable To produce gels. On the other hand, it is also possible, for example, to freeze the suspensions to dryness by means of freeze drying and to incorporate the residue obtained into an ointment base or cream.

The optimal concentration of active substance in the finished pharmaceutical preparations naturally depends on the type of active substance and the galenical preparation and must be determined in individual cases using the usual preliminary tests. As a rule, it will be sufficient to use pharmaceutical preparations which use 0.001 to 1 mg and preferably 0.005 to 0.1 mg of vitamin D analogs per g of preparation.

The following exemplary embodiments serve to explain the invention in more detail.

example 1

(Film method with subsequent high pressure homogenization)

0.9 g PC S 100 (manufacturer Lipoid KG, DE-Ludwigshafen), 0.1 g cholesterol and 10 mg (5Z, 7E, 22E) - (lS, 3R, 24R) -l, 3,24-trihydroxy-9 , 10-seco-cholesta-5,7,10 (19), 22-tetraen-25-carboxylic acid isopropyl ester are dissolved in 50 ml of 95% ethanol. The solution is then evaporated to dryness in a 500 ml round-bottom flask on a rotary evaporator, a lipid film forming on the glass wall. This lipid film is removed with 98.9 g of double-distilled water. The liposome suspension obtained is then homogenized with a high-pressure homogenizer (Microfluidizer® from Microfluid Corp. USA) at 400 MPA and 25 ° C. and filtered through a filter of 0.2 μm.

The liposome suspension obtained contains liposomes with an average size of 112 nm. The phosphatidylcholine content is 9 mg per g; the content of encapsulated! Active ingredient is 0.1 mg per g.

Example 2

0.9 g PC S 100, 0.1 g cholesterol and 10 mg (5Z, 7E, 22E) - (1S, 3R, 24R) -1,3,24 ~ trihydroxy-9, 10-seco-cholesta-5, 7, 10 (19), 22-tetraen-25-carboxylic acid isopropyl ester are dissolved in 50 ml of 95% ethanol.

The solution is then evaporated to dryness in a 500 ml round-bottom flask on a rotary evaporator, a lipid film forming on the glass wall. This lipid film is removed with 98.9 g of double-distilled water. The suspension obtained is then subjected to high-pressure extrusion, as described in PCT / DE93 / 00997, using Nucleopore® membranes with a decreasing pore size of 5.0, 1.0, 0.4, 0.2, 0.1 and 0.05 μm is used.

The liposome suspension obtained contains liposomes with an average size of 94 nm and otherwise has the same properties as the preparation described in Example 1.

Example 3

(Preparation of liposome suspensions and subsequent loading with active ingredient) 0.9 g PC S 100 and 0.1 g DSPG, Na (manufacturer Sygena LTD, CH-Liestal) are dissolved in 50 ml 95% ethanol, evaporated to dryness and the resulting lipid film is detached with 99 g bidistilled water. A high pressure extrusion is then carried out as described in Example 2.

50.0 g of the liposome suspension thus prepared are placed in an iodine number flask, with 2 mg (5Z, 7E, 22E) - (IS, 3R, 24R) -l, 3,24-trihydroxy-9,10-seco-cholesta - 5.7, 10 (19), 22-tetraen-25-carboxylic acid isopropyl ester, stirred for 18 hours at room temperature and then filtered through a filter with a pore size of 0.2 μm.

The liposome suspension thus obtained contains liposomes with an average size of 106 nm. The phosphatidylcholine content is 9.0 mg per g, the active ingredient content is 0.04 mg per g.

Example 4

(A modified reverse phase evaporation method)

0.5 g PC E 100 and 10 mg (5Z, 7E, 22E) - (lS, 3R, 24R) -l, 3,24-trihydroxy-9,10-seco-- cholesta-5,7,10 (19th ), 22-tetraen-25-carboxylic acid isopropyl ester are dissolved in 100 ml of dietyl ether and mixed with 50 ml of 0.015 M aqueous Tris buffer of pH 7.4. Then the two-phase mixture is homogenized in a high-pressure homogenizer (Microfluidizer®) at 20Pa and 23 ° C. The resulting emulsion is freed from diethyl ether on a rotary evaporator at 4000 Pa and 23 ° C. and the liposome suspension obtained is filtered through a 0.45 μm filter.

The liposome suspension obtained contains liposomes with an average size of 220 nm. The phosphatidylcholine content is 10 mg per g; the content of encapsulated! Active ingredient is 0.2 mg per g.

Examples 5 and 6

The liposome suspensions prepared according to Examples 1 and 3 are mixed with 0.18%

p-Hydroxybenzylmethylter, 0.02% p-Hydroxybenzylpropylester and 2% Hydroxyethylcellulose added and stirred for 5 minutes at 600 revolutions per minute and then briefly at 1000 revolutions per minute. The mixtures are then left to stand for 24 hours. The preparations have a medium-soft consistency, the viscosity value is approximately

30000 mPa / s. In the preparations, the liposomes are still suspended in the aqueous phase. You are intact.

Examples 7 and 8

(Preparation of a Liposomal Lipogel)

The liposome suspensions prepared according to Examples 1 and 3 are freeze-dried. The dried liposome cake is crushed with a drum mill and the resulting powder is triturated in portions with an ointment base consisting of petroleum jelly which contains 0.02% 2,6-di tert-butyl-4-methylphenol (= BHT) as an antioxidant contains that the active ingredient concentration in the finished ointment is 0.05 mg per g.

Claims

Claims:

1.) Topically applicable agent for the treatment and prophylaxis of alopecia, characterized in that it contains vitamin D analogs encapsulated in liposomes.

2.) Topically applicable agent according to claim 1, characterized in that it is in the form of a hydrogel or oleogel.