DISPOSITION OF ATOVAQUONE IN HUMANS

Atovaquone is an antiprotozoal compound with good in vitro stability a gainst metabolic inactivation. Previous human studies which did not in volve radiolabelling had not accounted for a substantial proportion of the dose. The possible metabolism of atovaquone in men was examined i n a radiolabelling study involving four healthy male volunteers. Radio activity was eliminated almost exclusively via the feces. All radioact ivity in plasma, urine, and feces was accounted for by atovaquone, wit h no evidence of metabolites. Radiolabelled atovaquone was administere d to a patient with an indwelling biliary tube after surgery. Biliary radioactivity was approximately 10- to 40-fold higher than that in pla sma and was accounted for by atovaquone. Atovaquone is not significant ly metabolized in humans but is excreted into bile against a high conc entration gradient.