The disposition of a novel tetrahydroquinoline, tiquinamide, in rats and patas monkeys.

The absorption of tiquinamide occurred rapidly and extensively in both rats and patas monkeys. The major site of localization of radioactivity was in the stomach in both species. Tiquinamide was 50-60% bound to rat plasma and 50-75% to monkey plasma. The elimination of unchanged drug from plasma took place rapidly, with half lives of 1.6 h in rats and 0.7 h in monkeys. Elimination of total radioactivity in the rat was very slow and monoexponential, with a half-life of 90 h. However, in the monkey it took place in a biphasic manner and most radioactivity was eliminated in the first phase with a half-life of 0.75 h. Possible reasons for the species difference in elimination are discussed. The principle route of excretion in both species was via the urine. Excretion was slower in the rat than in the monkey. In the former species, only 50% of the administered dose was excreted in the first 24 h after dosing, and a further 12% was recovered from the carcasses after 7 days. In the monkey, however, excretion was virtually complete in the first 6 h.