Stability-indicating HPLC method for the determination of nicardipine in capsules and spiked human plasma. Identification of degradation products using HPLC/MS

Abstract

In this stability-indicating, reversed-phase high-performance liquid chromatographic method for nicardipine (NIC), forced degradation has been employed and the formed degradants were separated on a C18 (150mm×3.9mm, 5μm) analytical column using a mobile phase consisted of 70% methanol: acetic acid containing 0.01M triethylamine with pH 4. The flow rate was 1.0mL/min and the photodiode array detection wavelength was 353nm. Forced degradation of the drug was carried out under acidic, basic, photolytic, and oxidative stress conditions. Chromatographic peak purity data indicated no co-eluting peaks with the main peaks. This method resulted in the detection of seven degradation products. Among these, two major degradation products from basic hydrolysis, one from oxidation by H2O2 and four from photolytic stress were identified by mass spectral data. A good linear response was achieved over the range of 0.5–40μg/mL with a limit of detection (LOD) of 0.011μg/mL and limit of quantification (LOQ) of 0.036μg/mL. The suggested method was successfully applied for the analysis of NIC in its commercial capsules, with mean% recovery value of 100.11±2.26%. The method was extended to the in vitro determination on NIC in spiked human plasma samples with mean% recovery of 99.04±5.67%. The suggested method was utilized to investigate the kinetics of photolytic induced degradation.