Rp HPLC Method for Simultaneous Estimation of Metformin and Sitagliptin

A new method was established for simultaneous estimation of Metformin and Sitagliptin by RP-HPLC method. The chromatographic conditions were successfully developed for the separation of Metformin and Sitagliptin by using Thermosil C18 (4.0×125 mm) 5.0µm column (4.6×50mm) 3.7µ, flow rate was 0.7 ml/min, mobile phase ratio was Methanol: Sodium acetate buffer (70: 30 % v/v), detection wave length was 252nm. The instrument used was WATERS HPLC Auto Sampler, Separation module 2695, photo diode array detector 996, Empower-software version-2. The retention times were found to be 2.566 mins and 3.417 mins. The % purity of Metformin and Sitagliptin was found to be 101.03% and 99.27% respectively. The system suitability parameters for Metformin and Sitagliptin such as theoretical plates and tailing factor were found to be 1540.37, 1.26 and 4348.8, 1.16, the resolution was found to be 2.4. The analytical method was validated according to ICH guidelines (ICH, Q2 (R1)). The linearity study of Metformin and Sitagliptin was found in concentration range of 50-250ppm and 5ppm-25ppm and correlation coefficient (r2) was found to be 0.999 and 0.999, % recovery was found to be 99.56% and 99.47%, %RSD for repeatability was 0.8and 0.82, % RSD for intermediate precision analyst 1 was 0.44 and intermediate precision analyst 2 was 0.19 respectively. The precision study was precision, robustness and repeatability. LOD value was 3.17 and 0.0172 and LOQ value was 5.80 and 0.212 respectively.