Abstract

BIOEQUIVALENCE STUDY OF TWO INJECTABLE TULATHROMYCIN FORMULATIONS (DRAXXIN® AND DRAXIFAR®) IN CALVES

Ashraf Elkomy* and Mohamed Aboubakr

ABSTRACT

The present study was designed to assess the comparative bio-equivalence of Draxxin® and Draxifar® in healthy calves after intramuscular injection (IM) of both products in a dose of 2.5 mg tulathromycin/kg b.wt. Ten calves were divided into two groups. The first group was designed to study the pharmacokinetics of Draxxin®, while the 2nd group was designed to study the pharmacokinetics of Draxifar®. Each calves in both groups was IM injected with 2.5 mg tulathromycin/kg b.wt. Blood samples were obtained from the jugular vein and collected immediately before and at 0.5, 1, 2, 4, 6, 8, 12, 24, 36, 48, 60, 72, 84, 96, 108, 120 and 132 hours after a single IM injection. The disposition kinetics of Draxxin® and Draxifar® following IM injection of 2.5 mg tulathromycin/kg b.wt, revealed that the maximum blood concentration of tulathromycin [Cmax] were 0.57 and 0.55 μg/ml and attained at [tmax] of 3.56 and 3.63 hours, for Draxxin® and Draxifar® respectively. In conclusion: Draxifar® is bioequivalent to Draxxin® since the ratios of Cmax, AUC0-132 and AUC0-∞ (T/R) for tulathromycin was 0.96, 0.89 and 0.89, respectively. These are within the bioequivalence acceptance range. Draxifar® and Draxxin® are therefore bioequivalent and interchangeable in calves.

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