Simultaneous determination of three carbapenem antibiotics in plasma by HPLC with ultraviolet detection.

A simple, precise and accurate high-performance liquid chromatography (HPLC) method using ultraviolet (UV) detection has been developed for simultaneous determination of carbapenem antibiotics: imipenem, meropenem and ertapenem in human plasma. Samples were spiked with ceftazidime as internal standard and proteins were precipitated by acetonitrile. Separation was achieved on a C8 column with a mobile phase composed of phosphate buffer 0.1M (pH 6.8) and methanol in gradient elution mode. Detection was performed at 298 nm. Calibration curves were linear from 0.5 to 80 mg/L for each compound, with correlation coefficients over 0.997. Intra- and inter-day validation studies showed accuracy between -4.5 and 8.1% and precision below 10.4%. Mean recoveries were 82.2, 90.8 and 87.7% for imipenem, meropenem and ertapenem, respectively. This method provides a useful tool for the therapeutic drug monitoring of carbapenems.