Determination of lansoprazole in biological fluids and pharmaceutical dosage by HPLC.

A simple and rapid (extractionless) high-performance liquid chromatographic method with UV detection at 230 nm was developed for the determination of lansoprazole in biological fluids and pharmaceutical dosage. Niflumic acid was added as internal standard. The separation was performed at ambient temperature on a C18 Spherisorb column with acetonitrile + 0.1 M sodium acetate (40:60, v/v, pH 7) as mobile phase. The retention time was 5.2 min for niflumic acid and 6.7 min for lansoprazole. The detection limit was 20 ng/ml using a 100 microl loop. The method was successfully applied to a pharmacokinetic study of lansoprazole in humans.