Functionalized β-cyclodextrin-based Potentiometric Membrane for the Selective Determination of Vildagliptin in Presence of its In-process Impurity

A novel vildagliptin selective electrode has been investigated using tetrakis (p-chlorophenyl) borate as cation exchanger in polymeric matrix of polyvinyl chloride plasticized with orth-nitro phenyl octyl ether. The proposed sensor was fabricated using hydroxy propyl β-cyclodextrin as ionophore and compared to ionophore free sensor. A stable and reliable response of vildagliptin within the concentration range of 1×10-1to1×10-4 mol.L-1 was obtained on using ionophore based sensor with detection limit down to 5×10-6 mol.L-1. Nernstian slope was 55.3 mV/decade over in aqueous medium (pH 7) was observed with fast response time. The selectivity coefficients calculated for L-proline as in-process impurity and different inorganic cations indicated excellent selectivity for vildagliptin. Hydroxy propyl β- cyclodextrin sensor displayed useful analytical characteristics for the determination of vildagliptin. The fabricated ionophore based sensor was validated and found to be accurate and precise compared with the manufacturer’s gradient HPLC method. Moreover, this potentiometric has advantage over previously published methods where no sample pretreatment is required.