Bioequivalence of a propylene glycol-based liquid dapsone preparation and dapsone tablets

The bioequivalence of a proprietary liquid dapsone preparation and commercially available dapsone tablets was studied. Twelve adult volunteers received dapsone doses with 8 oz of water one to two hours after their usual breakfast. Each subject received an initial 100-mg dose of a propylene glycol-based liquid preparation of dapsone and, two weeks later, a 100-mg dapsone tablet (both from Jacobus Pharmaceutical Company, Princeton, NJ). Blood samples were collected before and at intervals up to 96 hours after the administration of each dose. Serum dapsone concentrations were determined by high-performance liquid chromatography, and pharmacokinetic values were calculated by model-independent analysis. The area under the concentration-versus-time curve and the maximum serum concentration for the two formulations met the criteria for bioequivalence. Time to maximum serum concentration tended to be lower for the liquid, but not significantly. The liquid and tablet formulations of dapsone studied were found to be bioequivalent and may be used interchangeably.