A simple and rapid liquid chromatographic method for the determination of metronidazole and its hydroxymetabolite in plasma and cutaneous microdialysates.

A rapid, accurate, simple and low-cost method for quantitative determination of metronidazole and its hydroxymetabolite, in plasma and microdialysate samples, using tinidazole as an internal standard, has been developed. Metronidazole is widely used as a valuable agent for antiprotozoal as well as antibiotic therapy when anaerobic organisms are involved. Separation of the compounds studied was performed on a 120 x 4 mm analytical column, filled with LiChrosorb RP-8, 5 microm, the mobile phase consisted of 0.05 mol/L aqueous solution of potassium dihydrogen phosphate, adjusted to pH = 3.5 with orthophosphoric acid, methanol and acetonitrile (40:2:3. v/v/v). Detection was performed at 320 nm. Intra- and interserial precision was below 4.6% and 7.9%, respectively, for both the compounds studied. The presented method is suitable for pharmacokinetic studies.