RT Journal Article
SR Electronic
T1 Pharmacokinetic disposition of guanabenz in the rhesus monkey.
JF Drug Metabolism and Disposition
JO Drug Metab Dispos
FD American Society for Pharmacology and Experimental Therapeutics
SP 509
OP 514
VO 9
IS 6
A1 R H Meacham
A1 S T Chiang
A1 C J Kick
A1 S F Sisenwine
A1 W J Jusko
A1 H W Ruelius
YR 1981
UL http://dmd.aspetjournals.org/content/9/6/509.abstract
AB The pharmacokinetics of guanabenz (E-2,6-dichlorobenzylidene aminoguanidine acetate, Wy-8678) in rhesus monkeys given 14C-labeled and unlabeled drug were investigated. The radioactive dose was well absorbed after intragastric (ig) administration of 1 mg of the labeled drug per kg, as indicated by tissue and urinary recovery of the label. Excretion into urine accounted for 57 +/- 3 (SE)% of the radioactive ig dose. Recovery of radioactivity in urine after iv administration of 0.2 mg/kg was 79 +/- 0.6% of the radioactive dose. Less than 1% of the dose was recovered in urine as unchanged drug after either route of administration. Plasma concentration/time profiles after 1-mg/kg iv and ig doses were fitted by polyexponential equations with a terminal elimination half-life of 12.0 +/- 1.1 hr. A large volume of distribution (VSSD = 10.3 +/- 0.7 liters/kg) indicated extensive extravascular distribution of the drug, which was confirmed by 14C-distribution studies. The systemic clearance was 27.5 +/- 1.4 ml/min/kg with hepatic clearance appearing to be the major determinant in guanabenz elimination. Dose proportionality was evident from a comparison of areas under the plasma concentration-time curves (AUC) of 1- and 5-mg/kg ig doses. The low systemic availability of 0.19-0.31 reflects the extensive presystemic extraction (first-pass effect) of the drug. Similarities in the pharmacokinetics of guanabenz in man and the rhesus monkey indicate that the latter species may serve as a satisfactory model for man in disposition studies.