The pharmacokinetics and bioavailability of nomifensine maleate in healthy men.

Two studies were conducted in normal male volunteers to establish the pharmacokinetic parameters for nomifensine maleate and to determine the bioavailability of the drug from the Merital capsule intended for U.S. marketing. Single oral doses of 25, 100, and 200 mg of nomifensine maleate as aqueous solutions were administered to 24 men in the open-label Latin-square design pharmacokinetic study. In the bioavailability study, 24 men received single oral 50 mg doses of nomifensine maleate in a capsule or as an aqueous solution. Plasma levels of nomifensine were determined by radioimmunoassay and urinary levels of total nomifensine and its metabolites were assayed by thin-layer chromatography. There was a proportional increase in the area under the curve (AUC) with increasing dose, while peak plasma levels and amounts of total nomifensine and its metabolites excreted in the urine rose as dose increased. The pharmacokinetics of nomifensine are considered linear over the dose range tested. Nomifensine maleate was equally bioavailable from the 50 mg aqueous solution and the Merital capsule formulation.