A stability-indicating HPLC method for determination of folic acid and its related substances in tablets

Abstract

In this study, a simple stability-indicating HPLC method for determination of folic acid and its related substances in tablets was optimized and validated. Chromatographic separation was performed on Inertsil C8, 250 x 4.6 mm, 5 μm, using isocratic elution with mobile phase consisting of methanol and phosphate buffer (pH=6,4) (12:88, v/v %). The injection volume was 5 μL and the eluted compounds were monitored at 280 nm. The flow rate was 0.7 mL/min and the column temperature was maintained at 30 ˚C. Forced degradation studies were conducted to investigate the stability-indicating ability of the method. The method was validated according to the ICH guideline requirements with respect to selectivity/specificity, linearity, limit of detection, limit of quantification, accuracy, precision and robustness. The results from the forced degradation study confirmed satisfactory resolution between folic acid and obtained specified impurities (imp. A, imp. C, imp. D, imp. E and PABA) as well as satisfactory resolution between all other formed degradation products, proving that the method is stability-indicating. The optimized and validated method is selective and precise, capable of detecting and quantifying all folic acid related substances. The obtained results from validation parameters imply that the proposed method is suitable for its purpose and can be used for routine quantification of folic acid and its related substances in tablets.