Determination of metronidazole in vaginal tissue by high-performance liquid chromatography using solid-phase...

A sensitive high-performance liquid chromatographic (HPLC) method for the determination of metronidazole in vaginal tissue is reported. The method uses a Zorbax SB phenyl column with a 0.01 M aqueous monobasic potassium phosphate buffer (pH 4.0)-absolute methanol (85:15, v/v) as mobile phase at a flow-rate of 1.0 ml/min and detection at 313 nm. Tinidazole was used as the internal standard. The method employed homogenization of tissue followed by solid-phase extraction. The quantitation was achieved within 30 min with sensitivity in the ng/g range. Metronidazole was linear in the 100-2000 ng/g range. The accuracy and precision were in the 1-4% range for the drug and the limit of detection was approximately 100 ng/g based on a signal-to-noise ratio of 3 and a 1009-microliters injection.