Disposition of the novel anticancer agent vinorelbine ditartrate following intravenous administration in mice, rats and dogs.

1. KW-2307 (vinorelbine ditartrate, CAS 71486-22-1) is a new semisynthetic antitumour vinca alkaloid. Its pharmacokinetics, distribution and excretion were investigated following intravenous administration to mice (1.2 mg/kg), rat (0.12 and 1.2 mg/kg) and dogs (0.4 mg/kg). Dose levels are expressed as the free base. 2. Plasma concentrations of drug-related radioactivity declined in a bi- or tri-exponential manner, initially rapidly and the slowly (half-life of 35 h or more). Unchanged drug concentrations declined with terminal half-lives of 35.8 h in rats and 34.5 h in dogs: a terminal phase was not observed in mice