Bioanalytical Method Development and Validation for the Simultaneous Determination of Vildagliptin and Telmisartan in Rabbit Plasma Using RP-HPLC

A simple, reproducible bioanalytical method of liquid chromatography and PDA detector was developed and validated for the simultaneous Determination of Vildagliptin and Telmisartan in Rabbit Plasma using liquid-liquid extraction technique. K2 EDTA was used as anti-coagulant. Analytes were extracted by Methyl-tert-Butyl Ether (MTBE) and subsequent separation on a Kromasil C18 column (5 mu, 100 x 4.6 mm) using Acetonitrile : Methanol 75:25 v/ v as mobile phase at a flow rate of 1 mL/min and (40 +/- 1)degrees C column oven temperature. Analytes were monitored with PDA detector at an isosbestic point of 225 nm for both Vildagliptin and Telmisartan. Retention times of Vildagliptin and Telmisartan were found to be at 2.545 mins and 6.633 mins respectively. The method was validated over a linear (r(2) = 0.9979) concentration range of 24.979 - 5003.808 mu g/ml for Vildagliptin and 1.011-202.559 mu g/ml for Telmisartan. The inter-day and intra-day precisions were found to be less than 15% and the accuracy was all within +/- 15% (at LLOQ +/- 20%). The developed HPLC-PDA method was fully validated for all the other parameters as per FDA guidelines like selectivity, matrix effect, recovery and stability as well. Due to the high degree of sensitivity, very less time consuming, easy extraction procedure and low requirement of sample volume, the method will be applicable for therapeutic drug monitoring.