药代动力学与实验治疗学杂志

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Comparative Disposition Kinetics and Bioavailability of Ofloxacin after Extravascular Administration in Buffalo (Bubalus bubalis) Calves

Pratishtha Sharma, Ashok Gaur, Manmeet Singh and Satish K Garg

Comparative disposition kinetics of ofloxacin was studied in buffalo calves following its Intramuscular (IM) and Subcutaneous (SC) administration @ 5 mg/kg body weight. Plasma ofloxacin concentrations were determined by microbial assay method using E. coli as test organism. Ofloxacin could be determined in plasma within 2.5 min of drug administration and peak levels of 2.37 ± 0.06 and 2.20 ± 0.02 μg/ml were observed at 0.75 and 1.0 h after IM and SC administration, respectively. Blood levels of around 0.25 μg/ml were observed for up to 24 h and pharmacokinetics was best described by two-compartment open model following both the routes. Absorption and elimination half life values were found to be 0.14 ± 0.02 and 22.88 ± 81.97 h after IM administration while 0.18 ± 0.04 and 28.25 ± 2.04 h after SC administration. The AUC values after IM and SC administration were calculated to be 24.99 ± 0.95 and 28.24 ± 0.65 μg.h/ml, respectively while respective bioavailability values were found to be 116.23 ± 8.03 and 107.10 ± 10.22 per cent indicating almost complete absorption of ofloxacin following administration by either of the routes. Based on the efficacy predictor values, ofloxacin be administered to buffalo calves @ 5 mg/kg by IM or SC route and be repeated at 24 h interval. However, for bacterial isolates requiring higher drug concentrations, ofloxacin be administered at 7.5 mg/kg and be repeated at 12 h interval. Further, preferential use of SC route over IM route is recommended for ofloxacin administration to buffalo calves.