| 主权项 |
1. A foamable composition in an aerosol packaging assembly for treating skin comprising a prefoam emulsion composition and a liquefied or compressed gas propellant, the prefoam emulsion composition comprising:
a)
i) a suspended or entrapped active agent selected from the group consisting of benzoyl peroxide, imiquimod, acyclovir, zinc oxide, titanium oxide, an antibiotic, and a corticosteroid; orii) an encapsulated or entrapped or suspended drug insoluble in the prefoam emulsion; and b) a carrier comprising:
i) one or more surface-active agents;ii) about 0.01% to about 1% by weight of the emulsion composition of at least one pH sensitive polymeric additive comprising a polyacrylic acid polymer;iii) a hydrophobic solvent, wherein the hydrophobic solvent comprises at least 1% by weight of the emulsion composition of an oil;iv) water; andv) a buffer system, wherein up to about 2% by weight of the emulsion composition comprises the buffer system, wherein the buffer system is at a pH less than the pH of the prefoam emulsion before addition of the buffer system and is selected to provide a prefoam composition that is fluid at room temperature and that has a viscosity of less than about 8000 centipoises; wherein the liquefied or compressed gas propellant is at a concentration of about 3% to about 25% by weight of the foamable composition, wherein the pH sensitive polymeric additive is reversibly susceptible to buffer or pH adjuster, and the polymer together with the buffer system contributes to holding the active agent homogeneously dispersed in the foamable composition over a prolonged time, wherein the foamable composition is fluid at room temperature; and wherein the composition forms a breakable foam upon dispensing in which the active agent is homogenously dispersed. |
