Typically, said formulations are transparent, and the hydrocortisone is dissolved in said transparent formulations rather than suspended. A particular feature of the formulations of the invention is that they are stable-chemically stable, physically stable and microbiologically stable-over a long period of time, as required by many health authorities, and this without needing any preservative. By the absence of preservatives, the potential toxicological adverse effects of the latter, such as allergic or inflammatory reactions, are avoided. Moreover, the topical formulations of the invention show a surprisingly good delivery of the active substance, hydrocortisone.

Thus, the inventors of the present invention succeeded in providing a topical formulation of hydrocortisone which is stable over a long period of time, provides a pleasant, non-greasy and cooling feeling when applied to the skin of the human body, is typically transparent and does not contain any preservative, e. g. an ammonium salt preservative such as benzalkonium chloride or benzethonium chloride.

Therefore the invention relates to a pharmaceutical composition intended for topical use comprising (a) hydrocortisone or a topically acceptable salt or ester thereof, (b) a C2-C4-alkanol, (c) a co-solvent selected from poly-hydroxy-C2-C5-alkanes and poly-C2-C5-alkylene giycols, (d) water, (e) a cellulose-based gelling agent, (f) a compound selected from the group consisting of non-ionic surfactants and terpenoid compounds in a total amount of at least 0.1%, (g) a stabilizing agent, (h) an organic acid, and (i) a basic buffering agent in an amount sufficient to adjust the pH of the total composition to of from 3. 5 up to 6. 5.

All percentages given are percentages by weight (w/w), if not indicated otherwise. If any of the components of the compositions is addressed with indefinite article, e. g."a co-solvent", "an organic acid"etc., this is always meant in the sense of"at least one of", if not specified otherwise.

(a)-Hydrocortisone and its topically acceptable esters and salts, e. g. hydrocortisone 21-acetate, hydrocortisone 17-butyrate, hydrocortisone 21-phosphate disodium salt, hydrocortisone 21-sodium succinate or hydrocortisone 17-valerate, are well known glucocorticoid drugs suitable, inter alia, for topical use. They are beneficial in the topical treatment of e. g. inflammatory and allergic skin diseases, especially inflammatory lesions, such as insect bites, burns, atopic dermatitis, contact dermatitis, seborrheic dermatitis, neurodermatitis, seborrheic eczema or pruritus.

Typically, the topical pharmaceutical compositions according to the invention comprise the hydrocortisone component in pharmacologically effective amounts. Thus, it is present e. g. in an amount of from 0.1 up to 1.5%, especially of from 0.2 up to 1.2%, more especially of from 0.25 up to 1 %, and in particular of from 0.5 up to 1 %, of the total composition.

(b)-A C2-C4-alkanol is preferably a C2-C3-alkanol, especially ethanol or isopropanol and in particular ethanol. Typically the C2-C4-alkanol is present in an amount of from 10 up to 90%, preferably of from 20 up to 80%, and in particular of from 30 up to 50%, of the total composition.

(c)-Poly-hydroxy-C2-C5-alkanes have at least two hydroxy groups, preferably 2,3 or 4, and in particular 2 or 3 hydroxy groups. Preferred as C2-C5-alkanes are C2-C4-alkanes, and in particular ethane or propane. Preferred poly-hydroxy-C2-C5-alkanes are glycerin, ethylene glycol and propylene glycol. Poly-C2-C5-alkylene glycols are e. g. polyethylene glycol or polypropylene glycol, each having a molecular weight of from 200 up to 12000, preferably of from 250 up to 6000 and especially of from 300 up to 1500. Typically the co-solvent is present in an amount of from 1 up to 40%, preferably of from 5 up to 30%, and in particular of from 10 up to 20%, of the total composition. In particular preferred is a mixture of propylene glycol and glycerin, especially in a weight ratio of from 4: 1 up to 30: 1.

(d)-Water is typically present in an amount of from 5 up to 90%, preferably of from 10 up to 70%, and in particular of from 20 up to 60%, of the total composition.

(e)-A cellulose-based gelling agent is e. g. methyl or ethyl cellulose or a carboxy-or hydroxy-C-C4-alkyl cellulose, such as carboxymethyl, hydroxyethyl, hydroxypropyl, hydroxypropylmethyl or ethylhydroxyethyl cellulose. Preferred are hydroxyethyl cellulose, hydroxypropyl cellulose and hydroxypropylmethyl cellulose. The cellulose-based gelling agent is typically present in an amount of from 0.1 up to 10%, preferably of from 0.1 up to 6%, and in particular of from 0.5 up to 4%, of the total composition.

(f)-A non-ionic surfactant is e. g. a partial glycerin fatty acid ester, such as glycerin monostearate; a partial fatty acid ester of sorbitan or polyoxyethylene sorbitan, such as sorbitan monolaurate or polyethylene glycol (5 to 20) sorbitan monostearate or monooleate ; a polyoxyethylene (3 to 30) fatty alcohol ether, such as polyoxyethylene (3 to 12) lauryl ether, especially polyoxyethylene (3 or 4 or 6 or 12) lauryl ether (= Laureth-3, Laureth-4, Laureth-6, Laureth-12) ; or a polyoxyethylene fatty acid ester, such as polyoxyethylene (8 to 100) stearate. Preferred are Laureth- (3 to 12).

A terpenoid compound is e. g. camphor, 3-carene, carvacrol, carvone, chrysanthemic acid; cineol, e. g. 1,8-cineol (= eucalyptol) ; gefarnate, geraniol, linalool, limonen, menthol (especially laevo-menthol), eucalyptol, pulegone, thujone or thymol. Preferred are cineol and, in particular, menthol.

The total amount of (f) in the compositions of the invention is at least 0.1%, preferably at least 0.11 %, more preferably at least 0.2%, especially of from 0.2 up to 10%, and in particular of from 0.2 up to 2%. Most preferably, said compound is selected from Laureth-3, Laureth-4, Laureth-6 and Laureth-12.

(g)-Stabilizing agents are e. g. antioxidants, such as butylhydroxytoluene, or complex- forming agents, such as EDTA or a salt thereof, e. g. the EDTA disodium or calcium salt. It is typically present in an amount of from 0.01 up to 0.2%, preferably of from 0.01 up to 0.1%.

(h)-The organic acid serves inter alia as acidifying and buffering agent. Examples for organic acids are malic acid, tartaric acid, maleic acid, fumaric acid, lactic acid, succinic acid and, in particular, citric acid. It is typically present in an amount of from 0.01 up to 2%, preferably of from 0.1 up to 0.5%.

(i)-The basic buffering agent is e. g. sodium hydroxide, e. g. a 30% aqueous solution thereof, or ammonia, e. g. an aqueous solution thereof. Preferably, the pH of the total composition is adjusted to of from 4 up to 6.

Preferably, the invention relates to a pharmaceutical composition intended for topical use and comprising (a) 0.2-1.2% of hydrocortisone or a topically acceptable salt or ester thereof, (b) 20-80% of ethanol, isopropanol, or mixtures thereof, (c) 5-30% of at least one co-solvent selected from glycerin, ethylene glycol, propylene glycol, polyethylene glycol and polypropylene glycol, (d) 10-70% of water, (e) 0.1-6% of at least one cellulose-based gelling agent selected from methyl cellulose, ethyl cellulose, carboxymethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, hydroxypropylmethyl cellulose and ethylhydroxyethyl cellulose, (f) 0.2-10% of at least one compound selected from non-ionic surfactants and terpenoid compounds, (g) 0.01-0.2% of at least one stabilizing agent, (h) 0.01-2% of at least one organic acid, and (i) at least one basic buffering agent sufficient to adjust the pH of the total composition to of from 3. 5 up to 6. 5.

First and foremost, the invention relates to a pharmaceutical composition intended for topical use and comprising (a) 0.25-1% hydrocortisone or a topically acceptable salt or ester thereof, (b) 30-50% ethanol, (c) 10-20% of at least one co-solvent selected from glycerin, ethylene glycol and propylene glycol, (d) 20-60% of water, (e) 0. 5-4% of at least one cellulose-based gelling agent selected from hydroxyethyl cellulose, hydroxypropyl cellulose and hydroxypropylmethyl cellulose, (f) 0.2-2% of at least one non-ionic surfactant selected from laureth- (3 to 12) and menthol, (g) 0.01-0.1% of at least one stabilizing agent selected from antioxidants and complexing agents, (h) 0.1-0.5% of at least one organic acid selected from the group consisting of citric acid, malic acid, tartaric acid, maleic acid, fumaric acid, lactic acid and succinic acid; (i) at least one basic buffering agent selected from sodium hydroxide and ammonia in an amount sufficient to adjust the pH of the total composition to of from 3.5 up to 6.5.

The topical pharmaceutical compositions according to the invention are administered in a manner known per se. For example, they are applied e. g. once, twice or three times daily to the affected portions of the skin.

The invention further relates to the use of the components (a) through (i)-in the amounts indicated-for the manufacture of a topical pharmaceutical composition for the treatment of inflammatory and allergic skin diseases.

Moreover, the invention relates to a method of treating allergic and inflammatory skin diseases which comprises topically administering to a mammal in need of such treatment a therapeutically effective amount of one of the topical pharmaceutical compositions as specified herein above and below.

The manufacture of the topical pharmaceutical preparations is effected in a manner known per se, for example by dissolving the hydrocortisone component in the solvents present, or, if necessary, in a portion thereof. For example, the hydrocortisone component is dissolved in the organic solvents (b) and (c), then all other components are added, and the whole composition is thoroughly mixed.

The following examples are intended to illustrate the invention.

Example 1: A gel containing 1.0% of hydrocortisone Composition (a) hydrocortisone 1.0% (b) ethanol 96% (v/v) 40.0% (c') propylene glycol 15.0% (c") glycerin 1.0% (d) purified water 39.74% (e) hydroxyethyl cellulose 1.8% (f') laureth-4 1. 0% (f") laevo-menthol (mainly acts as perfume here) 0.09% (g) butylhydroxytoluene 0.02% (h) citric acid 0.3% (i) sodium hydroxide solution 30% 0.05% 100% Manufacture : (a) is dissolved in (b) and (c'). Then, (g), (f") as well as (e) are added to the solution ("solution 1"). All remaining components are dissolved in (d), and then solution 1 is slowly added thereto. Upon mixing a homogeneous gel is obtained.

Example 2: A gel containing 1.0% of hydrocortisone Composition (a) hydrocortisone 1.0% (b) ethanol 96% (v/v) 40. 0% (c') propylene glycol 15.0% (c") glycerin 1.0% (d) purified water 39.73% (e) hydroxyethyl cellulose 2.0% (f) laevo-menthol 0.9% (g) butylhydroxytoluene 0.02% (h) citric acid 0.3% (i) sodium hydroxide solution 30% 0.05% 100% The gel is manufactured in an analogous manner to Example 1.