METHOD FOR PREPARATION OF N-ACETYL CYSTEINE AMIDE OR DI- N-ACETYL CYSTEINE AMIDE AND DERIVATIVES

Provided herein are compositions and methods of providing an effective amount of an N-acetylcysteine amide (NACA) or diNACA sufficient to increase the concentration of NACA or diNACA in the affected tissue to biochemically reduce oxidative stress-related damage to tissue; utilizing NACA or diNACA that comprises at least one of impurities B1 or B2, which are indicative of NACA or diNACA manufactured by a process comprising: contacting cystine with methanol and a chlorinating reagent to form an organic solution containing cystine dimethylester dihydrochloride and optionally isolating and drying the cystine dimethylester dihydrochloride; combining the dried or undried cystine dimethylester dihydrochloride with triethylamine, acetic anhydride, and acetonitrile to form di-N-acetylcystine dimethylester; mixing the di-N-acetylcystine dimethylester with ammonium hydroxide to form di-N-acetylcystine amide (diNACA or NPI-002); and reducing the di-N-acetylcystine amide to N-acetylcysteine, NACA or NPI-001 with a reducing agent, an organic solvent, and a base.