RP-HPLC and HPTLC Methods for Simultaneous Estimation of Metformin Hydrochloride and Vildagliptin from Bulk and Marketed Formulation: Development and Validation

Abstract

The reversed-phase high performance liquid chromatography (RP-HPLC) and high performance thin layer chromatography (HPTLC) methods for simultaneous estimation of Metfomin Hydrochloride (MET) and Vildagliptin (VLD) in bulk and their marketed combined dosage form were developed. For RP-HPLC, separation was carried out using HiQsil C18HS (4.6mmo×250mm) analytical column and detection was carried out using variable wavelength detector. The mobile phase was composed of phosphate buffer (pH adjusted to 6 using 3M KOH): methanol: acetonitrile in the ratio of 50:30:20 v/v/v. Flow rate was kept at 0.8ml/min. The drugs- MET and VLD were retained at 3.7 minutes and 4.8 minutes respectively. The HPTLC method was developed using Camag HPTLC system. Silica Gel 60GF254 precoated TLC plates were used as stationary phase. The mobile phase was ammonium acetate in methanol (1% w/v): Toluene; (10:0.5). The detection of spots was carried out densitometrically at 214 nm in absorbance mode. The Rf values for MET and VLD were found to be 0.44 and 0.55 respectively. Performance characteristics of both of these RP-HPLC and HPTLC methods for simultaneous estimation of MET and VLD in bulk and their marketed combined dosage form were statistically validated as per the recommendations of ICH guidelines of analytical method validation. The RP-HPLC method was found to be linear across concentration range of 10-60µg/mL for MET and VLD respectively. For RP-HPLC the LOD values for MET and VLD were 1.09µg/ml and 1.70µg/ml respectively and LOQ values for MET and VLD were 3.32µg/ml and 5.15µg/ml respectively. The HPTLC method was found to be linear with across the range 1000-5000ng/spot and 500-2000ng/spot for MET and VLD respectively. For HPTLC the LOD values for MET and VLD were 17.22ng/spot and 34.60ng/spot respectively and LOQ values for MET and VLD were 52.20ng/spot and 104.85ng/spot respectively. Both of these RP-HPLC and HPTLC methods were found to be simple, specific, linear, accurate, precise and robust, hence any of these methods can be conveniently adopted for routine analysis of the formulations containing MET and VLD, for their simultaneous estimation.