Validated Univariate and Multivariate Spectrophotometric Methods for Simultaneous Determination of Pioglitazone and Glimepiride in their Binary Mixture and in Tablet Preparation

Abstract

Four simple, selective and accurate spectrophotometric univariate methods and two multivariate chemometric methods for resolving pioglitazone (PGZ) and glimepiride(GLM) in binary mixture were proposed, derivative ratio spectrophotometric method (DRSM), ratio difference spectrophotometric method (RDSM), isoabsorptive point coupled with 2nd derivative spectrophotometry (ISO point-D2) and mean centering of ratio spectra method (MCR). All methods are based on determination of two components of severely overlapped spectra. DRSM is based on the first derivative of ratio spectra at 266 nm of PGZ and 249.3 nm of GLM. RDSM is based on the amplitude ratio difference between 277.8 and 241.8 nm for PGZ and 242 and 225.7 nm of GLM. ISO point-D2 is based on determination of the total mixture at 253.3 nm isosbestic point while the second derivative of PGZ was determined at 272.8 nm without the interference of GLM. MCR is based on the mean centering of ratio spectra of PGZ at 278 nm and GLM at 242 nm. The two chemometric methods are principle component regression (PCR), and partial least square (PLS).The proposed methods were validated according to the ICH guidelines where accuracy, repeatability, and inter-day precision were found to be within the acceptable limits. The results obtained from the proposed methods were statistically compared with reported ones where no significant difference was observed.

Key words:

• Derivative ratio
• ratio difference
• isoabsorptive point
• mean centering
• PCR
• PLS
• pioglitazone
• glimepiride