Stable n-acetylcysteine compositions and methods for treating human skin therewith

A two phase water-in-silicone topical emulsion composition comprising:

• (a) from about 1% to about 60% of a silicone continuous phase comprising at least one liquid organopolysiloxane,
• (b) from about 30% to about 90% of an aqueous discontinuous phase comprising a safe and effective amount of a compound selected from the group consisting of N-acetylcysteine;
• a derivative of N-acetylcysteine selected from the group consisting of an ester of N-acetylcysteine, an amide of N-acetylcysteine, an anhydride of N-acetylcysteine, a thio-ester of N-acetylcysteine, and a thio-ether of the sulfhydryl moiety of N-acetylcysteine;
• a pharmaceutically acceptable salt of N-acetylcysteine;
• a pharmaceutically-acceptable salt of said derivative of N-acetylcysteine;
• or a mixture thereof, and
• (c) from about 0.1% to about 10% of an emulsifier for dispersing said discontinuous phase into said continuous phase.