Disposition and metabolism of [14C]-haloperidol in rats

Absorption, distribution, excretion and metabolism of [14C]-haloperidol in rats were studied after administration of 5 mg/kg. After oral and intramuscular administration, plasma levels of [14C]-haloperidol radioactivity reached the maximum at 1 h and decreased biphasically. The biphasic elimination was also observed after intravenous administration. The area under plasma level-time curve (AUC) from 0 to 24 h after intramuscular and oral administration was 110 and 87% of AUC after intravenous route, respectively. After intramuscular administration, levels of radioactivity in all tissues examined were higher than plasma and blood levels at 1 h. The lung, Harderian gland, pancreas, kidney, liver, spleen and adrenal had higher levels than other tissues. Most of tissue levels decreased virtually with similar half lives to plasma level and lowered to less than 1 microgram eq/g at 48 h, when negligible recoveries were found in most tissues. Findings concerning distribution obtained by whole-body autoradiography essentially agreed with those by above radiometry. Levels in the placenta and fetus in the pregnant rat were similar to each other and obviously higher than maternal blood level at 1 h after intramuscular administration but no ...Continue Reading