Simultaneous HPLC of Metformin, Glipizide and Gliclazide, and Metformin Uptake and Protection of HEI-OC1 from Hyperglycaemia

The antidiabetic drugs metformin, glipizide and gliclazide have been used for many years to control blood glucose levels. In recent years, they have gained importance in non-diabetic pharmacological purposes including cancer and hearing loss treatment. Co-administration of these therapeutics represents a challenge to some clinicians seeking an efficient, sensitive and rapid analytical method to use in the pharmacokinetic studies and the therapeutic monitoring of these agents. This research outlines the development and validation of a new precise, robust, sensitive, selective and rapid ion-pairing reversed-phase HPLC method for the simultaneous determination of a ternary mixture of metformin, glipizide and gliclazide in the same isocratic chromatographic run within 5 min. The limits of detection were 59.22 ng/mL for metformin, 169.48 ng/mL for glipizide and 151.29 ng/mL for gliclazide. The method was applied in quantifying metformin uptake by the auditory cell line HEI-OC1, to gain an insight into the kinetics of this biguanide in the organ of Corti. Metformin exhibited a concentration-dependent uptake by HEI-OC1 cells up to 5 mM, after which, saturation of the uptake was noticed. When HEI-OC1 cells were subjected to diabetes-simulated conditions, metformin was able to mitigate the hyperglycaemic stress and revealed a protective role in this cell line.