Abstract

BIO-EQUIVALENCE STUDY OF TWO INJECTABLE IVERMECTIN-CLOSANTEL FORMULATIONS (CLOSAMECTIN® AND CLOSAMECPLEX®) IN CALVES

Ashraf Elkomy* and Mohamed Aboubakr

ABSTRACT

The present study was designed to assess the comparative bio-equivalence of Closamectin® and Closamecplex® in healthy calves after SC injection of both products in a dose of (200 μg ivermectin and 5 mg closantel/kg b.wt). Ten calves were divided into two groups (each contains 5 calves). The first group was designed to study the pharmacokinetics of Closamectin ®, while the 2nd group was designed to study the pharmacokinetics of Closamecplex®. Each calf in both groups was Sc injected with (200 μg ivermectin and 5 mg closantel/kg b.wt). Blood samples were obtained from the jugular vein and collected immediately before and at, 1, 4, 8, 12, 24, 48, 72, 96, 120, 144, 168 and 192 hours after a single SC injection. The disposition kinetics of ivermectin in Closamectin® and Closamecplex® revealed that, the maximum blood concentrations [Cmax] were 48.66 and 47.44 μg/ml and attained at [tmax] of 32.07 and 31.89 hours, respectively. The disposition kinetics of closantel in Closamectin® and Closamecplex® revealed that, the maximum blood concentrations [Cmax] were 66.48 and 63.49 μg/ml and attained at [tmax] of 42.86 and 42.23 hours, respectively. In conclusion: Closamecplex® is bioequivalent to Closamectin® since the ratios of Cmax, AUC0-192 and AUC0-∞ (T/R) for ivermectin were 0.97, 0.96 and 0.95 respectively and the ratios of Cmax, AUC0-192 and AUC0-∞ (T/R) for closantel were 0.95, 0.94 and 0.94 respectively. These are within the Bio-equivalence acceptance range. Closamectin® and Closamecplex® are therefore bioequivalent and interchangeable in calves.

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