Application of first-derivative UV-spectrophotometry, TLC-densitometry and liquid chromatography for the simultaneous determination of mebeverine hydrochloride and sulpiride.

Three methods are described for the simultaneous determination of mebeverine hydrochloride (MB) and sulpiride (SU) in combined pharmaceutical tablets. The first method depends on first-derivative ultraviolet spectrophotometry, with zero-crossing measurement method. The first derivative amplitudes at 214.2 and 221.6 nm were selected for the assay of MB and SU, respectively. Calibration graphs follow Beer's law in the range of 10-30 and 2-8 microg/ml(-1), and the linearity was satisfactory (r = 0.9999), for MB and SU, respectively. The second method was based on the application of the thin layer chromatographic separation of both drugs followed by the densitometric measurements of their spot areas. After separation on silica gel GF254 plates, using ethanol: diethyl ether: triethylamine (70:30:1 v/v) as the mobile phase, the chromatographic zones corresponding to the spots of MB and SU were scanned at 262 and 240 nm, respectively. The calibration function was established in the ranges of 4-12 microg for MB and 2-8 microg for SU. The third method was an internal standard procedure based on high performance liquid chromatographic separation of the two drugs on a reversed-phase, Bondapak CN column. The detection was done at 243 nm using buclizine hydrochloride as internal standard. All chromatographic methods showed good linearity, precision and reproducibility. No spectral or chromatographic interference from the tablet excipients were found. The proposed methods were successfully applied to the assay of commercial tablets and content uniformity test. The procedures were rapid, simple and suitable for quality control application.