Comparative validation of amisulpride determination in pharmaceuticals by several chromatographic, electrophoretic and spectrophotometric methods.

Nine accurate methods for determination of amisulpride in tablets: reversed phase high pressure liquid chromatography (RP-HPLC), aqueous capillary electrophoresis (CE), non-aqueous CE, normal phase (NP) and reversed-phase (RP) high performance thin layer chromatography (HPTLC) with densitometry and videodensitometry, and direct and derivative UV spectrophotometry were developed and validated. The HPLC was carried out using Nova-Pak C8 column and mobile phase consisted of acetonitrile-methanol-phosphate buffer pH 4.50 (15:5:80, v/v/v) with flow rate 1 mL min(-1) and UV detection at 225 nm. The moclobemide was used as the internal standard. CE was performed using 75 microm x 82 cm fused silica capillary (65 cm effective), the internal standard was quetiapine. Detection was carried out at 225 nm. For aqueous analysis, the 30 mM phosphate buffer pH 6.00, 30 kV voltage and 30 degrees C temperature were chosen, non-aqueous determination was performed with ammonia acetate 1 mM in acetonitrile-methanol (1:1, v/v), 30 kV voltage and 25 degrees C temperature. NP-HPTLC was carried out using HPTLC silica F254 plates, developed with hexane-ethanol-propylamine (5:5:0.1, v/v/v) through 9 cm distance. RP-HPTLC was developed with HPTLC RP8F254 plates, with mobile phase of tetrahydrofuran-phosphate buffer pH 3.50 (4:6, v/v), distance 4.5 cm. Both analyses were performed in horizontal chambers and scanned with densitometer at 275 nm or videodensitometer at 254 nm. UV spectrophotometry was carried out in methanol, using 224 nm for direct assay and 258 nm (D1) for derivative assay. The precision and accuracy of all the methods were complexively compared. The highest accuracy was observed in RP-HPTLC, the highest precision was achieved in non-aqueous CE method. The differences were not significant, so all the elaborated methods can be used in routine analysis.