Identification and quantitation of impurities in dapsone preparations

Chromatographic and fluorometric procedures were developed to isolate and quantitate small amounts of 2,4'-diamino-diphenyl sulfone and 4-aminodiphenyl sulfone in pharmaceutical preparations of the antileprosy drug 4,4'-diaminodiphenyl sulfone (dapsone). Identification was accomplished by comparison with authentic compounds employing UV absorption, fluorometry, and mass spectrometry in addition to TLC and high-pressure liquid chromatography.