Development and validation of SI/RS-UHPLC-PDA method for olmesartan medoximil and metoprolol succinate related substance

INTRODUCTION: Olmesartan medoximil (OLM) and Metoprolol succinate (MPS) in fixed dose combination (FDC) tablet formulation prescribed extensively. Stability indicating (SI) method for impurities and related substance (RS) test quantitates the amount of these analytes in formulation; the manuscript presents stability indicating SI/RS-UHPLC-PDA method for OLM and MPS and their impurities.
METHODS: Well-resolved separation of all analytes achieved with gradient elution on Shimadzu on Shimpack GIST-C18 (100mm X 2.1mm, 2 micron) column maintained at 25 °C. Mobile phase-A consist of 0.1% Orthophosphoric acid in water and mobile phase-B was acetonitrile at a flow rate of 0.4 ml/min, data integrated at 225 nm and 16 min. of short runtime for satisfactory elution of all the peaks.
RESULTS: Proposed SI/RS-UHPLC-PDA method was developed and validated as per ICH guidelines. System suitability test complied by all eluted peaks of the interest with acceptable linearity, recovery and precision. Specificity, robustness and method sensitivity parameters determined; all the parameters found to be within the limits. All impurities and stress-degraded peaks were well resolved.
DISCUSSION AND CONCLUSION: The proposed method found to be simple, fast, linear and accurate. Further, the method is precise, robust and specific; suitable for routine IPQC during API manufacturing, stability and impurity profiling studies of the titled bulk analytes. Furthermore, the method can be extended to assess the levels of impurities formed during life cycle of new FDCs of titled analytes.