Excretion and metabolism of intramuscularly administered [14C]-haloperidol decanoate in rats.
Urinary, fecal and biliary excretion, together with enterohepatic circulation, of radioactivity were studied after intravenous (50 mg eq/kg) and intramuscular (5 and 50 mg eq/kg) administration of [14C]-haloperidol decanoate in rats. The composition of urinary and biliary metabolites was also examined. The rate of excretion after intravenous administration lowered rapidly with the half-life of about 1.5 days and about 95% of dose was excreted in excreta within 10 days. Shortly after intramuscular administration, the rate of excretion lowered rapidly but then more gradually later (half-lives after administration of 5 and 50 mg eq/kg were 16.4 and 11.2 days, respectively). About 90% of dose was excreted within 42 days after intramuscular administration. About 1.6% of dose/day was excreted in the bile during 15-17 days after intramuscular administration, of which about 30% was reabsorbed within 24 h (enterohepatic circulation). The major urinary metabolite was p-fluorophenylaceturic acid and the biliary metabolite, glucuronide and sulfate of haloperidol. No unchanged decanoate was detected in the excreta.
Matsunaga
Y
Y
Nambu
K
K
Oh-e
Y
Y
Miyazaki
H
H
Hashimoto
M
M
D000818:Animals; D001646:Bile / Q000378:metabolism; D002250:Carbon Radioisotopes; D004764:Enterohepatic Circulation; D005243:Feces / Q000032:analysis; D006220:Haloperidol / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000378:metabolism / Q000652:urine; D007273:Injections, Intramuscular; D007275:Injections, Intravenous; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D013997:Time Factors
D002250:Carbon Radioisotopes; C033563:haloperidol decanoate; D006220:Haloperidol