In the present work, a simple, cost effective, reproducible and reliable method for simultaneous estimation of Glimepiride and Pioglitazone-HCl in bulk and marketed formulation using simultaneous equation was developed and validated. The developed method involved measurement of absorbances at wavelength of 228 nm and 265.5 nm ( absorption maxima of Glimepiride and Pioglitazone-HCl respectively), which these obeyed the principle of simultaneous equation method. Both the drugs obeyed Beer-Lambert's law in concentration ranges (For Glimepiride 4-20 and for Pioglitazone-HCl 10-50 mcg/ml). The...