Stability-indicating methods for the determination of sumatriptan succinate

Four stability-indicating methods were developed for the determination of sumatriptan succinate in the presence of its degradation products. The first method depends on the quantitative densitometric evaluation of thin-layer chromatography of sumatriptan succinate in the presence of its degradation products without any interference. Cyclohexane-dichloromethane-diethylamine (50:40:10 v/v/v) was used as a mobile phase and the chromatogram was scanned at 228 nm. This method determines sumatriptan succinate in the concentration range l-8 microg per spot with mean percentage recovery 100.52+/-1.23%. The second and third methods depend on the use of first-derivative (D(1)) and second-derivative (D(2)) spectrophotometry at 234 and 238 nm, respectively. These methods determine the drug in the concentration range 1.25-10 microg x ml(-1) with mean percentage recovery 99.91+/-1.01% and 99.96+/-1.13% for (D(1)) and (D(2)), respectively. The fourth method depends on the use of ratio derivative spectrophotometric technique. The amplitude in the first derivative of the ratio spectra at 235 nm was selected to determine the cited drug in the presence of its degradation products. Calibration graph is linear in the concentration range 1.25-10 microg x ml(-1) with mean percentage recovery 100.19+/-1.19%. The suggested methods were successfully applied for determining sumatriptan succinate in bulk powder, laboratory-prepared mixtures and pharmaceutical dosage forms (Imigran tablet) with good accuracy and precision. The results obtained by applying the proposed methods were statistically analyzed and compared with those obtained by the reported method.