A stability indicating LC method for felodipine

A stability indicating reversed-phase liquid chromatographic (RP-LC) method was developed for the assay of felodipine as a bulk drug and in pharmaceuticals. The chromatography was performed on a C18 column. Eluents were monitored by UV detection at 238 nm using the mobile phase methanol-potassium dihydrogen orthophosphate (pH 3.5; 0.01 M) (75:25, v/v). The method was statistically validated for linearity, accuracy, precision and specificity. The linearity of felodipine peak area responses was demonstrated within the concentration range of 1-7 microg/ml. The limits of detection and quantitation were 150 and 500 ng/ml, respectively. The method was demonstrated to be precise, accurate and specific with no interference from the tablet excipients and separation of the drug peak from the peaks of the degradation products (oxidative degradation, photodegradation, acid and base degradation). The results indicated that the proposed method could be used in a stability assay.