Quantitative analysis of sulpiride and impurities of 2-aminomethyl-1-ethylpyrrolidine and methyl-5-sulphamoyl-2-methoxybenzoate in pharmaceuticals byhigh-performance thin-layer chromatography and scanning densitometry

A simple and reliable thin-layer chromatographic method for determining sul piride and impurities of 2-aminomethyl-1-ethylpyrrolidine and methyl-5-sulp hamoyl-2-methoxybenzoate was developed and validated. A methylene chloride- methanol-ammonia solution (25%; 18 + 2.8 + 0.4, v/v) solvent system is used for separation and quantitative evaluation of chromatograms. The chromatog raphic plate is first scanned at 240 nm to locate chromatographic zones cor responding to sulpiride and methyl-5-sulphamoyl-2-methoxybenzoate. Then 2-a minomethyl-1-ethylpyrrolidine is derivatized in situ with ninhydrin, and re sulting colored spots are measured at 500 nm. The method is reproducible an d convenient for quantitative analysis and purity control of sulpiride in i ts raw material and in its dosage forms.