CHARACTERIZATION OF OSELTAMIVIR PHOSPHATE API AND SIMULTANEOUS QUANTIFICATION AND VALIDATION OF ITS IMPURITIES BY UPLC

Objective: The purpose of the study is to develop a high sensitive and short runtime method to quantify oseltamivir phosphate impurities (C and D) and characterization of oseltamivir phosphate API. Methods: The active pharmaceutical ingredient (API) characterization was done using spectroscopic techniques such as mass, infrared spectroscopy (IR), differential scanning calorimetry (DSC), proton nuclear magnetic resonance (H-NMR), phosphorus nuclear magnetic resonance (P-NMR), carbon-13 nuclear magnetic resonance (C13-NMR), and two-dimensional nuclear magnetic resonance (2D-NMR). The impurities (C and D) quantification was done using ACQUITY UPLC BEH C18- 100 mm × 2.1 mm, 1.7 μm column connected to ACQUITY UPLC with PDA detector. The optimized chromatographic conditions were achieved at 0.3 mL/min flow rate using gradient system with 0.1% orthophosphoric acid in water and acetonitrile as mobile phase. Both impurities are measured at λmax 210 nm at 30°C column temperature. Results: The finalized method has given good peak shape and resolution for impurity-C and impurity-D at Rt = 3.39 and 4.33 min, respectively, and the quantification method is linear and its r2 > 0.999 as a correlation coefficient. The recoveries of impurity-C and impurity-D were found in the range of 100±15% at 0.05, 0.1, and 0.15 and limit of quantitation (LOQ) % concentration levels. The other validation parameters such as specificity, system precision, sensitivity, method precision, ruggedness, robustness, and solution stability were established for this method, and the results are satisfactory as per International Council for Harmonization (ICHQ2). Conclusion: The characterization data confirm the structure of oseltamivir phosphate active pharmaceutical ingredient (API). The validated method shall be used for regular analysis as well as release analysis in quality control (QC).