Simple and sensitive method for determination of metronidazole in human serum by high-performance liquid chromatography

A simple and sensitive HPLC method for determination of metronidazole in hu man plasma has been developed. A step of freezing the protein precipitate a llowed an efficient separation of aqueous and organic phases minimizing the noise level and improved therefore the limit of quantitation (10 ng ml-L u sing I mi of plasma sample). The separation of compounds was performed on a RP 18 column with acetonitrile-aqueous 0.01 M phosphate solution (15:85, v /v) as mobile phase. Detection was performed by UV absorbance at 318 nm. Me tronidazole was well resolved from the plasma constituents and internal sta ndard. An excellent linearity was observed between peak-height ratios plasm a concentrations over a concentration range of 0.01 to 10 mu g ml(-1). With in-day and between-day precision (expressed by relative standard deviation) and accuracy (mean error in per cent) did not exceed 4% between 1 and 10 m u g ml(-1) and 8.3 and 7.2% respectively for the limit of quantitation. The method is suitable for bioavailability and pharmacokinetic studies in huma ns. (C) 1998 Elsevier Science BN. All rights reserved.