Halobetasol foam composition and method of manufacture thereof

A storage stable, foamable composition comprising on a weight basis:

• a) 0.02 to 0.10% halobetasol or its pharmaceutically acceptable salts, esters, and solvates;
• b) 40 to 60% ethyl alcohol;
• c) 0.1 to 5.0% Emulsifying Wax, NF;
• d) 0.05 to 1.0% cetostearyl alcohol;
• e) 0.05 to 1.0% polyoxyl 20 cetostearyl ether;
• f) 1 to 10% propylene glycol;
• g) 30 to 40% water;
• h) greater than 0.0% and less than 0.0005% benzoic acid;
• and
• i) 3.25 to 5.75% propellant, wherein the composition has a pH of between about 4.0 to 6.3, and wherein the composition is produced by:
• forming a homogenous solution including (b)-(h), wherein the solution is formed at a temperature of at least about 65° C.;
• cooling the homogenous solution to a temperature of below about 50° C.;
• adding halobetasol, or a pharmaceutically acceptable salt, ester, or solvate thereof, to the cooled solution and forming a homogenous solution;
• filling an aerosol canister with the homogenous solution while the solution is at a temperature of above about 35° C.;
• and
• charging the canister with the propellant thereby forming the foamable composition;
• wherein the composition is stable for greater than 36 months at 25° C., regardless of whether or not the composition is void of a buffer, as determined by assay of an active amount of halobetasol.