Topical Pharmaceutical Foam Composition

Abstract

A stable topical alcohol-free aerosol foam containing one or more keratolytic agents is provided. The foam-forming formulation is an oil-in-water emulsion which contains one or more hydrofluoroalkane (HFA) propellants and one or more keratolytic agents. The keratolytic agent may be present in either phase of the emulsion or dispersed in the emulsion. The oil phase may consist at least in part of the HFA propellant. The foam is stable on the skin for at least 5 minutes at body temperature and disappears into the skin upon rubbing or after prolonged standing. The formulations may not contain additional co-solvents or non-HFA co-propellants. The formulations demonstrate reduced intensity of the odor and/or color associated with the keratolytic agent(s) as compared to conventional formulations containing keratolytic agents.

1 - 49 . (canceled) 
     
     
         50 . An aerosol foam formulation comprising:
 (a) a retinoid dissolved or dispersed in an oil-in-water emulsion; and   (b) a propellant consisting essentially of one or more hydrofluoroalkanes;   
       wherein 
       the propellant is present in from about 5% to about 30% by weight of the formulation. 
     
     
         51 . The formulation of  claim 50 , wherein the concentration of the retinoid is from about 1% to about 60% of the formulation. 
     
     
         52 . The formulation of  claim 50 , wherein the retinoid is selected from the group consisting of retinoic acid, retinol, retinal, etretinate, acitretin, tazarotene, bexarotene, and adapalene. 
     
     
         53 . The formulation of  claim 50 , wherein the retinoid is retinoic acid. 
     
     
         54 . The formulation of  claim 50 , wherein the retinoid is tretinoin, isotretinoin, or alitretinoin. 
     
     
         55 . The formulation of  claim 50 , further comprising one or more active agents selected from the group consisting of antibiotic agents, antimicrobial agents, anti-acne agents, antibacterial agents, antifungal agents, antiviral agents, steroidal anti-inflammatory agents, non-steroidal anti-inflammatory agents, anesthetics, antipruriginous agents, antiprotozoal agents, anti-oxidants, antihistamines, hormones, vitamins, skin-soothing agents, sunscreens, and combinations thereof. 
     
     
         56 . The formulation of  claim 50 , further comprising one or more excipients selected from the group consisting of surfactants, emollients, emulsifiers, stabilizing agents, chelating agents, antioxidants, buffers, stabilizers, preservatives and combinations thereof. 
     
     
         57 . The formulation of  claim 50 , further comprising an antioxidant. 
     
     
         58 . The formulation of  claim 50 , wherein the hydrofluoroalkane is selected from the group consisting of 1,1,1,2-tetrafluoro ethane (134a), 1,1,1,2,3,3,3-heptafluoropropane (227), and combinations thereof. 
     
     
         59 . The formulation of  claim 50 , wherein the hydrofluoroalkane is 1,1,1,2-tetrafluoroethane (134a). 
     
     
         60 . The formulation of  claim 50 , wherein the formulation does not comprise a co-solvent or co-propellant. 
     
     
         61 . The formulation of  claim 50 , wherein the retinoid is selected from the group consisting of retinoic acid, retinol, retinal, etretinate, acitretin, tazarotene, bexarotene, and adapalene; and the hydrofluoroalkane is selected from the group consisting of 1,1,1,2-tetrafluoroethane (134a), 1,1,1,2,3,3,3-heptafluoropropane (227), and combinations thereof. 
     
     
         62 . The formulation of  claim 50 , wherein the retinoid is selected from the group consisting of retinoic acid, retinol, retinal, etretinate, acitretin, tazarotene, bexarotene, and adapalene; the hydrofluoroalkane is selected from the group consisting of 1,1,1,2-tetrafluoroethane (134a), 1,1,1,2,3,3,3-heptafluoropropane (227), and combinations thereof; and the formulation does not comprise a co-solvent or co-propellant. 
     
     
         63 . The formulation of  claim 50 , wherein the retinoid is selected from the group consisting of retinoic acid, retinol, retinal, etretinate, acitretin, tazarotene, bexarotene, and adapalene; and the hydrofluoroalkane is 1,1,1,2-tetrafluoroethane (134a). 
     
     
         64 . The formulation of  claim 50 , wherein the retinoid is selected from the group consisting of retinoic acid, retinol, retinal, etretinate, acitretin, tazarotene, bexarotene, and adapalene; the hydrofluoroalkane is 1,1,1,2-tetrafluoroethane (134a); and the formulation does not comprise a co-solvent or co-propellant. 
     
     
         65 . The formulation of  claim 50 , wherein the retinoid is retinoic acid; and the hydrofluoroalkane is selected from the group consisting of 1,1,1,2-tetrafluoroethane (134a), 1,1,1,2,3,3,3-heptafluoropropane (227), and combinations thereof. 
     
     
         66 . The formulation of  claim 50 , wherein the retinoid is retinoic acid; the hydrofluoroalkane is selected from the group consisting of 1,1,1,2-tetrafluoroethane (134a), 1,1,1,2,3,3,3-heptafluoropropane (227), and combinations thereof; and the formulation does not comprise a co-solvent or co-propellant. 
     
     
         67 . The formulation of  claim 50 , wherein the retinoid is retinoic acid; and the hydrofluoroalkane is 1,1,1,2-tetrafluoroethane (134a). 
     
     
         68 . The formulation of  claim 50 , wherein the retinoid is retinoic acid; the hydrofluoroalkane is 1,1,1,2-tetrafluoroethane (134a); and the formulation does not comprise a co-solvent or co-propellant.