Method for treating diseases mediated by proteases

A method for the treatment of disorders mediated by proteases in mammals that result in skin or mucosal lesions selected from the group consisting of lichen planus, canker sores (aphthous ulcers), and bullous diseases, comprising:

• topically applying to the skin or mucosal lesion an effective amount of a derivative of N-acetylcysteine of the formula ##STR3## wherein R.sup.1 is H, alkyl, aryl, alkaryl, aralkyl, alkyloxyalkyl, aryloxyalkyl, an amino acid salt formed by the reaction of the amino group of a naturally occurring amino acid with the carboxylic acid group of the N-acetylcysteine, an amine salt formed by the reaction of an amine-containing antibiotic with the carboxylic acid group of the N-acetylcysteine, or an inorganic cation, and
• R.sup.2 is H, alkyl, aryl, alkaryl, aralkyl, alkyloxyalkyl, aryloxyalkyl, C(O or S) alkyl, C(O or S) aryl, C(O or S) alkaryl, C(O or S) aralkyl, C(O or S) alkyloxyalkyl, C(O or S) acyloxyalkyl, phosphate, or an inorganic cation;
• the residue of a saturated or unsaturated fatty acid;
• the residue of lactic acid, retinoic acid, or ascorbic acid;
• or the residue of an alkyl or aromatic dicarboxylic acid;
• or a pharmaceutically acceptable salt thereof, optionally in a pharmaceutically acceptable carrier for topical administration.

A method for the treatment of disorders mediated by proteases in mammals that result in skin or mucosal lesions selected from the group consisting of lichen planus, canker sores (aphthous ulcers), and bullous diseases, comprising:

• systemically administering an effective amount of a derivative of N-acetylcysteine of the formula ##STR4## wherein R.sup.1 is H, alkyl, aryl, alkaryl, aralkyl, alkyloxyalkyl, aryloxyalkyl, an amino acid salt formed by the reaction of the amino group of a naturally occurring amino acid with the carboxylic acid group of the N-acetylcysteine, an amine salt formed by the reaction of an amine-containing antibiotic with the carboxylic acid group of the N-acetylcysteine, or an inorganic cation, and
• R.sup.2 is H, alkyl, aryl, alkaryl, aralkyl, alkyloxyalkyl, aryloxyalkyl, C(O or S) alkyl, C(O or S) aryl, C(O or S) alkaryl, C(O or S) aralkyl, C(O or S) alkyloxyalkyl, C(O or S) acyloxyalkyl, phosphate, or an inorganic cation;
• the residue of a saturated or unsaturated fatty acid;
• the residue of lactic acid, retinoic acid, or ascorbic acid;
• or the residue of an alkyl or aromatic dicarboxylic acid;
• or a pharmaceutically acceptable salt thereof, optionally in a pharmaceutically acceptable carrier for systemic administration.