title: The pharmacokinetics of primaquine in calves after subcutaneous and intravenous administration.
abstract: The pharmacokinetics of primaquine was studied in calves of 180-300 kg live weight. Primaquine was injected at 0.29 mg/kg (0.51 mg/kg as primaquine diphosphate) intravenously (IV) or subcutaneously (SC) and the plasma concentrations of primaquine and its metabolite carboxyprimaquine were determined by high-performance liquid chromatography. The extrapolated concentration of primaquine at zero time after IV administration was 0.50 +/- 0.48 microgram/ml (mean +/- SD) which decreased with an elimination half-life of 0.16 +/- 0.07 h. Primaquine was rapidly converted to carboxyprimaquine after either route of administration. The peak concentration of carboxyprimaquine was 0.50 +/- 0.08 microgram/ml at 1.67 +/- 0.15 h after IV administration. The corresponding value was 0.47 +/- 0.07 micrograms/ml at 5.05 +/- 1.20 h after SC administration. The elimination half-lives of carboxyprimaquine after IV and SC administration were 15.06 +/- 0.99 and 12.26 +/- 3.06 h, respectively. The areas under the concentration-time curve for carboxyprimaquine were similar following either IV or SC administration of primaquine; the values were 11.85 +/- 2.62 micrograms.h/ml after the former and 10.95 +/- 2.65 micrograms.h/ml after the latter. The mean area under the concentration-time curve for primaquine was less than 0.1 micrograms.h/ml after either route of administration.
authors.affiliation: National Veterinary Assay Laboratory, Tokyo, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Yoshimura
authors.forename: Y S
authors.initials: YS
authors.lastname: Endoh
authors.forename: Y
authors.initials: Y
authors.lastname: Ishihara
authors.forename: S
authors.initials: S
authors.lastname: Nakamura
authors.forename: Y
authors.initials: Y
authors.lastname: Inoue
mesh_terms: D000818:Animals; D002417:Cattle / Q000378:metabolism*; D002851:Chromatography, High Pressure Liquid / Q000662:veterinary; D006207:Half-Life; D007275:Injections, Intravenous / Q000662:veterinary; D007279:Injections, Subcutaneous / Q000662:veterinary; D011319:Primaquine / Q000008:administration & dosage / Q000493:pharmacokinetics*
chemical_list: D011319:Primaquine