Pharmaceutical spray composition comprising a vitamin D analogue and a corticosteroid

1. A sprayable, storage stable, substantially anhydrous topical composition comprising

a therapeutically effective amount of about 0.00001-0.05% w/w of calcipotriol or calcipotriol monohydrate and

a therapeutically effective amount of about 0.0005-1% of a betamethasone ester,

the calcipotriol or calcipotriol monohydrate and the betamethasone ester being dissolved in a propellant comprising dimethyl ether or a mixture of dimethyl ether and one or more C 3-5 alkanes, wherein the propellant is present in an amount of 50-90% w/w of the composition,

the composition further comprising

0.1-10% of an oily co-solvent selected from the group consisting of polyoxypropylene-15-stearyl, ether, polyoxypropylene-11-stearyl ether, polyoxypropylene-14-butyl ether, and polyoxypropylene-10-cetyl ether or polyoxypropylene-3-myristyl ether; and

10-50% w/w of a pharmaceutically acceptable lipid carrier solubilized or suspended in said propellant, the lipid carrier comprising one or more paraffins which upon application on skin and evaporation of the propellant mixture form a semi-solid and occlusive layer at the site of application.

2. The composition according to claim 1 , wherein the betamethasone ester is betamethasone dipropionate or betamethasone valerate.

3. The composition according to claim 1 , wherein the C 3-5 alkane is n-butane and/or isobutane.

4. The composition according to claim 3 , wherein the ratio of n-butane and/or isobutane to dimethyl ether is in the range of 6:1-0:1 v/v.

5. The composition according to claim 1 comprising 3-45% w/w of the lipid carrier.

6. The composition according to claim 1 comprising 55-70% w/w of the propellant.

7. The composition according to claim 1 , comprising 0.5-3% w/w of the oily co-solvent.

8. The composition according to claim 1 , wherein the paraffin is selected from paraffins consisting of hydrocarbons with chain lengths from C 5 to C 60 , the chain lengths peaking at C 14-16 , C 18-22 , C 20-22 , C 20-26 , C 28-40 , and C 40-44 as determined by gas chromatography.

9. A method of treating a dermatological diseases or condition, the method comprising administering to a patient in need thereof a therapeutically effective amount of a composition according to claim 1 , wherein the dermatological disease or condition is selected from the group consisting of psoriasis, pustulosis palmoplantaris, ichtyosis, dermatitis, rosacea and acne.

10. The composition according to claim 1 , wherein the C 3-5 alkane is selected from the group consisting of n-propane, isopropane, n-butane, and isobutane.

11. The composition according to claim 8 , further comprising a lipophilic viscosity-increasing agent capable of imparting to the lipid carrier the property of forming a semi-solid and occlusive layer on skin on application and evaporation of the propellant, said viscosity-increasing agent being selected from the group consisting of microcrystalline wax, silicone wax and hydrogenated castor oil, or mixtures thereof, and an isoparaffin.

12. The composition according to claim 4 , wherein the ratio of n-butane and/or isobutane to dimethyl ether is in the range of 5:1-1:2 v/v.

13. The composition according to claim 4 , wherein the ratio of n-butane and/or isobutane to dimethyl ether is in the range of 4:1-1:1 v/v.

14. The composition according to claim 4 , wherein the ratio of n-butane and/or isobutane to dimethyl ether is in the range of 4:2-1:1 v/v.

15. The composition according to claim 4 , wherein the ratio of n-butane and/or isobutane to dimethyl ether is in the range of 4:2-4:3 v/v.

16. The composition according to claim 1 , comprising 1-2.5% w/w of the oily co-solvent.

17. The composition according to claim 1 , comprising 1.5-2% w/w of the oily co-solvent.