[Determination of metronidazole in gastric juice by high performance liquid chromatography]

Metronidazole (MTZ) is the first chosen drug of anti-anaerobe which was recommended by World Health Organization. In this paper a high performance liquid chromatographic (HPLC) method has been developed to determine the concertration of MTZ in human gastric juice. Gastric juice was obtained by intubation after taking drug, then the sample was precipitated with ethanol to remove proteins, centrifuged, filtered and finally assayed by HPLC. The operating conditions were reversed phase C18 column (4mm x 150mm), CH3OH:KH2PO4 (5mmol/L, pH 4.0) = 10:90 mobile phase with flow rate of 1.5mL/min and detection wavelength at 320nm. The standard working curve was Y = -1.63 + 1.15X, with r = 0.9999, n = 7. The linear range was 2.5-200mg/L. The detection limit was 0.4mg/L. The average recovery was 96.0% and the coefficient of variation was 3.07%. This method can be applied to guide clinical therapy and pharmaceutical research.