Determination of free imipenem in human plasma by HPLC

WEN Ai-ping; LI Zhe; LI Ren; YU Jun-xian; CHENG Sheng; JI Xiao-jun; SHI Li-min; DUAN Mei-li

Abstract：Objective:To establish the HPLC method for determining the concentration of free imipenem in human plasma. Methods:Prior to analysis, free imipenem was isolated from plasma samples using ultraifltration and centrifugation. Then, the extracts were injected directly into an Agilent Zorbax SB-C8 column (4.6 mm × 250 mm, 5 μm). The mobile phase was consisted of acetonitrile-ammonium acetate solution (0.5 mol·L-1), and the gradient elution mode was applied in chromatographic separation. The lfow rate was 1.0 mL·min-1. Ceftazidime was chosen as internal standard. The detection wavelength was set at 298 nm. The column temperature was 30℃.Results:The linear range of the calibration curve was 0.3–100.0 μg·mL-1 with a good correlation coefifcient (r > 0.999). The average recovery rates of quality control samples (0.5, 2.0, 30.0, 75.0 μg·mL-1) were (104.54 ± 3.17)%, (99.70 ± 1.04)%, (98.93 ± 1.12)% and (101.29 ± 2.23)%, respectively. The intra-day RSD was equal to or less than 3.03%, and inter-day RSD was equal to or less than 5.11%.Conclusion:The method was accurate, sensitive and simple, which was suitable for the therapeutic drug monitoring and clinical pharmacokinetic study of imipenem.