Abstract
An antifungal naphthoquinone, lawsone methyl ether, was semisynthesized by methylation of lawsone. It exhibited low acute toxicity with a LD 50 of 70.7 mg/kg upon intraperitoneal administration in mice. An oral preparation of 0.5 % lawsone methyl ether in sodium carboxymethyl cellulose oral base appeared to be stable under a heating-cooling cycle test. Lawsone methyl ether in oral base did not cause any skin irritation under a primary skin irritation test and a cumulative skin irritation test. In contrast, the solution of lawsone methyl ether, potassium salt, produced erythema with some papulosquamous in the cumulative skin irritation test.