Simple and efficient method for enantioselective determination of omeprazole in human plasma

A practical and selective HPLC method for the separation and quantification of omeprazole enantiomers in human plasma is presented. C18 solid phase extraction (SPE) cartridges were used to extract the enantiomers from plasma samples and the chiral separation was carried out on a Chiralpak AD column protected with a CN guard column, using ethanol:hexane (70:30) as the mobile phase, at a flow rate of 0.5 ml/min. The detection was carried out at 302 nm. The method proved to be linear in the range of 10-1000 ng/ml for each enantiomer, with a quantification limit of 5 ng/ml. Precision and accuracy, demonstrated by within-day and between-day assays, were lower than 10%.