Abstract

AGE-RELATED CHANGES IN THE PHARMACOKINETICS OF FLORFENICOL AFTER INTRAMUSCULAR ADMINISTRATION IN SHEEP AND GOAT

*Mohamed El-Hewaity and Hanem El-Gendy

ABSTRACT

The comparative pharmacokinetic profile of florfenicol was studied in one-month and one-year old sheep and goat following intramuscular injection of 20 mg/kg body weight. Florfenicol concentrations in serum were controlled by microbiological test method utilizing Bacillus subtilis (ATCC 6633) as test organism. Following intramuscular administration of florfenicol in one-month and one-year old sheep and goat, serum concentration-time data were adequately described by a two-compartment open model. The absorption half-lives were 0.259, 0.361, 0.306 and 0.322 h, respectively. The maximum serum concentrations were significantly increased in one-year old sheep and goat compared to one-month old sheep and goat. The elimination half-life and MRT values of florfenicol were longer in one-month old sheepand goat compared to one-year old sheep and goat. The elimination processes were delayed in one-month old sheep and goat in contrary to one-year old sheep and goat. The in vitro serum protein-binding tendencies were 22.61% and 20.49% for one-month and one-year old sheep, respectively. While, the in vitro serum protein-restricting inclinations were 20.34% and 19.21% for one-month and one-year old goat, individually. In view of this study and monetarily, an ideal intramuscular dose regimen of florfenicol would be 20 mg/kg body weight once every day in one-month and one-year old sheep and goat to accomplish and keep up the therapeutic serum levels within safe limits. The pharmacokinetic profile of florfenicol in sheep and goat reveals that it may be therapeutically effective against most susceptible micro-organisms involved in most common infections in sheep and goat. It could be inferred that anatomical and physiological changes identified with development could adjust the kinetic of florfenicol in sheep and goat.

Keywords: Age-related pharmacokinetics florfenicol intramuscular sheep and goat.