Development and validation of spectrophotometric methods for estimating amisulpride in pharmaceutical preparations

Five simple, sensitive, accurate and rapid visible spectrophotometric methods (A, B, C, D and E) have been developed for estimating Amisulpride in pharmaceutical preparations. These are based on the diazotization of Amisulpride with sodium nitrite and hydrochloric acid, followed by coupling with N-(1-naphthyl)ethylenediamine dihydrochloride (Method A), diphenylamine (Method B), beta-naphthol in an alkaline medium (Method C), resorcinol in an alkaline medium (Method D) and chromotropic acid in an alkaline medium (Method E) to form a colored chromogen. The absorption maxima, lambda(max), are at 523 nm for Method A, 382 and 490 nm for Method B, 527 nm for Method C, 521 nm for Method D and 486 nm for Method E. Beer's law was obeyed in the concentration range of 2.5-12.5 microg mL(-1) in Method A, 5-25 and 10-50 microg mL(-1) in Method B, 4-20 microg mL(-1) in Method C, 2.5-12.5 microg mL(-1) in Method D and 5-15 microg mL(-1) in Method E. The results obtained for the proposed methods are in good agreement with labeled amounts, when marketed pharmaceutical preparations were analyzed.