A comparative study of the pharmacokinetics of isometamidium chloride in sheep and goats

A study was carried out to determine and compare the pharmacokinetics of isometamidium in groups of six animals each of sheep and goats treated by intramuscular injection with isometamidium chloride (Samorin®, Rhone Merieux, Lyon, France) at 0.5 mg/kg body weight. The animals were bled at pre-determined time intervals and serum isometamidium concentrations monitored using isometamidium-ELISA for a period of over 60 days post-treatment. Pharmacokinetic evaluation was carried out using a non-compartment analysis. Mean residence time (MRT) in sheep was higher but not significantly different from that observed in goats. Whereas the mean Cmax values observed in both species were similar, the Tmax value of 12.7 h obtained in goats was significantly longer (P < 0.05) suggesting a slower rate of absorption of the drug from injection site. Also, the elimination half-life obtained in goats of 188 h was significantly shorter (P < 0.05) than that observed in sheep suggesting rapid elimination rate of the drug in the later. At 60 days no drug was detectable in both sheep and goats. © 2003 Elsevier B.V. All rights reserved.