I.A. Wasfi, J. Almasri1, M. Elghazali, Nawal A. Alkatheeri, A.A. Abdel Hadi, F. Altayeb,C.E. Uboh3, Ishar M. Barezaig, J.A. Rudy3, L.R. Soma2 and K. Singh
Camel Racing Laboratory, Forensic Science Laboratory, P.O. Box 253, Abu Dhabi, United Arab Emirates
1Veterinary Research Centre, P.O. Box 72437, Al Ain, United Arab Emirates
2University of Pennsylvania, School of Veterinary Medicine, New Bolton Centre Campus, Kennett Square, PA 19348, USA,
3PA Equine Toxicology & Research Centre, West Chester State University, Department Chemistry,
West Chester, PA 19382, USA
ABSTRACT
The present study investigated the disposition of heptaminol after intravenous administration and the effect of diprophylline on the pharmacokinetics of heptaminol in camels. Seven healthy camels (3 males and 4 females) 4-7 years old weighing 300 – 400 kg were used. The study was an open longitudinal design in which each animal served as its own control. In study phase 1, each camel received an intravenous dose of heptaminol (10 mg/kg). Blood samples were collected at 0 (predose) and 5, 10, 15, 30, 45, 60 min and at 1.5, 2, 2.5, 3, 3.5, 4, 5, 6, 7, 8 and 12 h after drug administration. Phase 2 was conducted one week later in which i.v. doses of heptaminol and diprophylline (10 mg/kg each) were administered and blood samples were collected as in phase 1. Serum concentrations of heptaminol were determined in duplicate by a validated HPLC method. Pharmacokinetic analysis for serum heptaminol for each camel was performed using least squares nonlinear regression analysis. The disposition of heptaminol was best described by a bi-exponential equation. The results obtained (mean ± SD) for heptaminol and heptaminol with diprophylline were, respectively, as follows: Total body clearances (ClT) were 645.5 ± 109.9 and 511.1 ± 114.1 ml/kg.h, the elimination half-lives (t1/2b ) were 2.00 ± 0.21 and 2.09 ± 0.34 h and the steady state volumes of distribution (VSS) were 1432.2 ± 129.5 and 1279.1 ± 310.0 ml/kg, respectively. Diprophylline administration had no significant effect on the pharmacokinetics of heptaminol in camels. Heptaminol and metabolite could be detected in urine samples for 24-48 h after an i.v. dose of 10 mg/kg body weight.
Key words: Camels, clearance, heptaminol, metabolism, pharmacokinetics, racing
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