Sensitive and selective spectrophotometric determination of pantoprazole sodium in pharmaceuticals using permanganate

A simple visible spectrophotometric method is described for the determination of pantoprazole sodium sesquihydrate (PSS). The method is based on the formation of a brown colored product on treating PSS with permanganate in neutral medium, the absorbance being measured at 350 nm. The experimental conditions for the assay were optimized. The absorbance is found to increase linearly with the concentration of PSS and the calibration graph is linear in the range of 25-40.0 mu g ml(1) with a linear regression coefficient of 0.998. The calculated molar absorptivity value is 1.27x10(4) I mol(1) cm(-1) and the corresponding Sandel sensitivity is 0.0341 mu g cm(-2). The limits of detection (LOD) and quantification (LOQ) are calculated to be 0.49 and 1.47 mu g ml(1), respectively. Intra-day and inter-day accuracy expressed as relative error were better than 20% and the corresponding precision (RSD) was less than 25 %. The developed and validated method was applied to the determination of the active ingredient in a tablet dosage form and the results obtained agreed well with those of the reference method. The accuracy and reliability of the method were ascertained by performing recovery experiments via standard-addition procedure