Micellar liquid chromatographic determination of felodipine in tablets and human plasma with fluorescence detection: application to stability studies and content uniformity testing

Abstract

A simple and sensitive stability indicating HPLC method was developed and validated for the quantitative determination of felodipine (FLP) in the presence of its degradation products, using atenolol as an internal standard. The separation was performed on a C18 column using a micellar mobile phase consisting of 85 mM sodium dodecyl sulfate, 25 mM phosphate buffer and 6.5% pentanol at pH 7. Fluorescence detection set at 240 nm (excitation) and 440 nm (emission) was used. A good linear response was achieved in the range of 0.05–15 μg mL⁻¹, with a lower detection limit (LOD) of 0.011 μg mL⁻¹ and a quantification limit (LOQ) of 0.032 μg mL⁻¹. The suggested method was successfully applied for the analysis of FLP in its commercial tablets, with a mean % recovery value of 100.69 ± 0.24%. The method was extended to the in vitro determination of FLP in spiked human plasma samples with a mean % recovery of 99.62 ± 0.51%. The suggested method was utilized to investigate the kinetics of alkaline induced degradation. Moreover, the method was successfully applied to the content uniformity testing of FLP tablets, adopting the USP guidelines.