DEVELOPMENT OF A VALIDATED RP-HPLC METHOD FOR SEPARATION AND DETERMINATION OF PROCESS-RELATED IMPURITIES OF OMEPRAZOLE IN BULK DRUGS

A gradient reversed phase liquid chromatographic (RP-LC) method has been developed and subsequently validated for the determination of omeprazole and its process-related impurities (noted as: impurity A, 13, C, D, G, H).. Separation was achieved with a Zorbax Extend C-18 column and acetonitrile: water: triethylaminel1% (pH adjusted to 9.5) as eluent, at a flow rate of 0.8 mL/min. UV detection was performed at 280 nm. The described method was linear over a range of 40.6-203 mu g/mL for omeprazol, 0.9556-14.334 mu g/mL for impurity A, 1.1568-17.352 mu g/mL for impurity B, 1.0772-16.158 mu g/mL for impurity C, 1.289-19.344 mu g/mL for impurity D and 0.7968-11.952 mu g/mL for impurity H. The accuracy of the method has been demonstrated at 5 concentration levels in the range of 60-140% of the specification limit and the recovery of impurities was found to be in the range of 90-109%. The method is simple, rapid, selective, accurate and useful for indicating the stability of omeprazole from dosage forms. The method can be useful in the quality control of bulk manufacturing and pharmaceutical formulations.