Development and Validation of Rp-hplc Method for the Simultaneous Estimation of Metformin and Pioglitazone in Combined Dosage Form

In this paper we are presenting development and validation of an improved method for the simultaneous estimation of metformin hydrochloride (MET) and pioglitazone (PIO) using high-performance liquid chromatography (HPLC). A Phenomenex, Onyx monolithic C18 column (150x4.6mm) was used with a mobile phase containing a mixture of 25 mM sodium dihydrogen phosphate (PH 3.65 with orthophosphoric acid): acetonitrile (60: 40 % v/v). The flow rate was 1.0 ml/min and effluents were monitored at 230 nm, and eluted at 2.17min (MET) and 6.21min (PIO). The pooled % RSD for repeatability of the percentage amount recovered for MET and PIO were found to be 0.42 and 0.315. The percentage recovery of the trueness for MET was 99.87% ± 1.5 and for PIO was 99.22% ± 1.03 (n=3). The method was successfully used to analyze fixed-dose tablets samples of MET and PIO.