Stability Indicating Method for the Determination of Related Substancesin Felodipine Solid Dosage Form and in the Drug Substance by RP HPLC
Background: Methods were not available in the monographs like United States Pharmacopeia, British pharmacopeia and European pharmacopeia and also in the literature for the determination of three related impurities namely Impurity A, B and C in Felodipine solid dosage form with a shorter runtime using RP HPLC. Method: A simple RP HPLC method was developed and validated for the quantification of Felodipine Impurity A, B and C in Felodipine solid dosage form and in drug substance. This method was developed on waters alliance using Phenomenex Gemini column C18 5 mm,150 x 2.0 mm i.d, using the isocratic program with the mobile phase ratio of 0.02 mM ammonium acetate adjusted to pH 5 and acetonitrile (55:45,v/v) with a flow rate of 0.7 mL/min. The lmax is at 240 nm. Results: Forced degradation was performed as per ICH guidelines and no interference of the impurities with the known peaks was found. Precision was found between 0.1 and 0.2% The Limit of detection and quantification for Felodipine and impurity A; Impurity B and C were 0.05 and 0.15 mg/mL respectively. The linearity correlation coefficient was found to be >0.999 for Impurity A and Felodipine; Impurity B and C of concentration range 0.2 30.0 mg/mL and 0.2 8.0 mg/mL respectively. The method accuracy was assessed for Felodipine and its impurities at four levels (LOQ, 50% 100% and 150% and the recovery ranged from 95% to 106% Conclusion: The method was found to be precise, reliable, accurate and robust.