RESUMEN
We developed simple, rapid, accurate, precise and sensitive spectrophotometric methods for the determination of ISPI in tables. The proposed methods are based on the formation of ion-pair complexes between the examined drug with BPB, AB in alkaline buffer at pH [9.0-9.5] and EO in buffer at pH=6.5, the complexes were extractable with dichloromethane which can be measured at the optimum lambda [max]. beer's law is obeyed in the concentration ranges a 0.96-14.4 micro g.ml[-1], 0.481-7.213 micro g.ml[-1] and 0.962-28.85 micro g.ml[-1] for the complexes ISPI-BPB, EO-ISPI and AB-ISPI respectively. The proposed methods were directly and easily applied to ISPI pharmaceutical preparations with accuracy, with results from recovery experiments ranging between 99.22 and 100.10% for BPB, 98.55 and 102.29% for EO and 98.75 and 101.93% for AB methods. The low relative standard deviation values indicate good precision and high recovery values indicate accuracy of the proposed methods. Therefore the proposed methods have been successfully applied to the determination of drug in commercial tablets