A gel containing 5% (w/w) dapsone, a synthetic derivative of diamino-sulfone with anti-infective properties. A structural analog of p-aminobenzoic acid (PABA), dapsone inhibits dihydropteroate synthase (DHPS), an enzyme important in folate synthesis, resulting in a depletion of the folate pool and a reduction in the amount of thymidylate available for DNA synthesis. Check for active clinical trials using this agent. (NCI Thesaurus)