A simple rapid and precise isocratic reversed phase chromatographic method was developed for assay (quantative determination) of metformin HCl in bulk drug (API). The chromatographic separation was achieved on Intersil ODS 3V (250X4.6 mm, 5μ) column using 0.025 M dibasic potassium phosphate and 0.005 M hexane sulphonic acid sodium salt in 1000 ml water adjust pH-3.0 with phosphoric acid and ratio of buffer to acetonotrile 93:7 as a mobile phase. Forced degradation studies were performed for metformin HCl bulk drug using (Concentrated H2SO4), base (NaOH), oxidation (30% H2O2), Heat (60°C) and UV light (254 and 365 nm). Degradation was not observed for metformin HCl sample during stress conditions like UV, light, heat, acid, base, oxidation. Peak purity test confirms metformin HCl peak was homogenous in all stress conditions. The mass balance of metformin HCl was close to be 100 in all stress conditions. The percentage recovery of metformin HCl was observed 100.08% by the formula % recovery = slope x 100. The metformin HCl sample solution and mobile phase were found to be stable atleast 48 hours. Robustness of the analytical method was determined by deliberately changing the analytical condition of wavelength detection, pH of mobile phase, flow rate of mobile phase and percentage buffer content. So assay of metformin HCl sample obtained under each changed condition was compaired with mean value of method precision the overall relative standard deviation should below 2.0%. The developed method was validated with respective linearity, accuracy, precision, system suitability, specificity and forced degradation studies perform the stability indicating power of the method.
Metformin HCl, Stability indicating RPLC, forced degradation, Validation, API
