Objective: To establish a RP HPLC method for the determination of
cefoperazone in dog serum and study on the
pharmacokinetics
of cefoperazone
administered alone and with tazobactam in dogs. Methods: Six healthy dogs was administered intravenously a single dose of cefoperazone 1.6g or cefoperazone tazobactam 2.0g. Cefoperazone in dog serum was determined by the newly developed RP HPLC method. The mobile phase consisted of triethylamine acetic acid∶acetic acid∶methanol∶water=1.5∶1.5∶250∶747(V/V), the eluate was monitored at 230 nm and the flow rate was 1.0ml/min. The pharmacokinitic parameters were obtained and compared between cefoperazone and cefoperazone tazobactam. Results: The calibration curve of cefoperazone was linear within the range of 2~1000mg/L with r =0.9999, the average recovery was (102.6±6.09)%. The within day RSD and between days RSD were no more than 4.24% and 5.20% respectively. The serum drug concentration time course in dogs after a single dose of 2.0g cefoperazone and 1.6g cefoperazone tazobactam conformed to the two compartment model. Area under the concentration time curve (AUC 0→∞ ) was (486.17±117.98) and (469.74±71.49)mg·h/L; half time ( t 1/2β ) was (0.96±0.13) and ( 0.85 ±0.17)h for cefoperazone and cefoperazone tazobactam respectively. Conclusion: The result of statistical comparison showed that pharmacokinitic parameters of cefoperazone administered alone and with tazobactam in dogs have no significant difference.