Validated HPLC-UV detection method for the simultaneous determination of ceftolozane and tazobactam in human plasma

A simple, rapid, economical and sensitive HPLC-UV method was developed for the simultaneous quantification of ceftolozane and tazobactam in plasma samples.

After deproteinization followed by a liquid-liquid back-extraction, the compounds were separated on a C18 column (150 mm × 4.6 mm, 5 μm) with UV-visible detection at 220 nm. The mobile phase consisted of acetonitrile and potassium dihydrogenphosphate buffer at pH 3.0 (8:92, v/v), delivered isocratically at a flow rate of 1.0 ml/min and at a column oven temperature of 30°C. Cefepime was used as an internal standard.

Linearity was achieved in the concentration range of 0.50-100.00 μg/ml for ceftolozane and 0.25-50.00 μg/ml for tazobactam. The intra- and interday precision showed good reproducibility with coefficients of variation of less than 9.26% for ceftolozane and 9.62% for tazobactam.

The sample preparation procedure avoids expensive or time-consuming steps used by other previously published methods. The methodology was validated according to standard guidelines and was used for quantification of ceftolozane and tazobactam in plasma samples from critically ill patients.