Validation of a method for pantoprazole and its sulfone metabolite in goat plasma using high performance liquid chromatography

A selective method for the quantitation of pantoprazole and its metabolite in goat plasma was developed and validated. Chloroform was used for drug extraction and separation occurred on a Symmetry C₁₈ column. A combination of sodium phosphate dibasic (0.1 M, pH 7.5) and acetonitrile were used as the mobile phase (64:36, v/v) while absorbance was measured at 290 nm. With a sample size of 0.1 mL the lower limit of quantification (LLOQ) was 0.01 µg/mL. The intra-assay variability for pantoprazole ranged from 3.4 to 10% while the metabolite ranged from 3.3% to 8.7% The inter-assay variability ranged from 2.6 to 9.7% and 3.3 to 7.5% for pantoprazole and its metabolite. The recovery was over 95% for both pantoprazole and its metabolite, pantoprazole sulfone. The method was used to quantify both pantoprazole and its metabolite and was useful for pharmacokinetic studies.