Electroanalytic examination of some drugs used in diabetes treatment with voltametric method

Dipeptidyl peptidase 4 inhibitor (DPP4-I), one of the drug groups used as antidiabetic agents; It was first produced in 2006 as stagliptin. Drugs used as DPP-4 inhibitors are generally vildagliptin, saxagliptin, alogliptin and denagliptin. Metformin is an oral drug that is commonly used in the treatment of Type 2 Diabetes and increases insulin sensitivity. In this study, a new application of a disposable pencil graphite electrode (PGE) for the determination of Vildagliptin and Metformin, which are the drugs used in the treatment of diabetes, is presented. Electrochemical oxidation of vildagliptin showed an irreversible and diffusion-controlled adsorption oxidation peak at approximately 1.13 V by cyclic voltammetry. Particular attention has been paid to the use of square wave voltammetry on the surface of PGE and glassy carbon (GC) electrodes (for comparison) in aqueous solutions without surfactant and surfactant over a wide pH range (2.0-12.0). Using square wave voltammetry, the current showed a linear correlation in PBS buffer at pH 9.0 with a concentration between 2.94 µM and 49.98 µM. At the concentration of 2.94 µM (n = 9), the limit of detection (LOD) of 8.20 nM (2.48 ng mL-1) and a relative standard deviation of 2.95% were calculated. Electrochemical properties and quantification of Metformin (MET), which is one of the drugs used as an antidiabetic agent, was carried out using pencil graphite electrode (PGE) in NaOH (0.1 M) environment. This compound gave an irreversible peak of oxidation at about 1.28 V. Using square wave voltammetry in NaOH environment, the current showed a linear correlation with a concentration of 2.76 - 24.8 µM. At a concentration of 2.76 µM (n = 9), the limit of detection (LOD) of 9.03 nM (1.495 ng L-1) and a relative standard deviation of 3.25% were calculated. The developed voltammetric method was successfully applied for Vildagliptin and Metformin analysis in pharmaceutical preparations and urine samples without any separation.