DETERMINATION OF IMIPENEM IN PLASMA BY HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHY FOR PHARMACOKINETIC STUDIES IN PATIENTS

A rapid and simple HPLC method is described for the determination of i mipenem in human plasma. After blood collection, plasma was separated by centrifugation and immediately stabilized with 3-morpholinopropanes ulfonic acid (MOPS) and ethylene glycol solution (1:1). The sample pre paration, before injection into HPLC, was ultrafiltration. The mobile phase was boric acid buffer. The imipenem was detected at 300 nm and c ilastatin sodium, coadministered, did not interfere. Calibration curve s in human plasma were linear from 0.1 to 100 mu g/ml. The limit of de tection was 0.030 mu g/ml. Inter-day precision at 0.1 mu g/ml, determi ned as the coefficient of variation, was 6.26%. Only 250 mu l of plasm a was required in our assay. Due to the limited stability of imipenem [G.B. Smith et al., J. Pharm. Sci., 79 (1990) 732], stability studies in plasma were done to establish appropriate storage conditions. The a ssay was applied to pharmacokinetic studies in patients.