Synthesis, characterization and toxicity profiling of graphene oxide-metformin hydrogel as a sustained release system for metformin in-vitro

We report here a sustained release system of metformin hydrochloride (MH) for its application in-vitro. Metformin hydrochloride (MH) conjugated graphene oxide (GO) hydrogel was synthesized and well-characterized by spectroscopic techniques like UV-Visible spectroscopy, Fourier-transform infrared spectroscopy (FT-IR). UV-Vis spectra showed a characteristic peak of GO at 232 nm and a shoulder at 315 nm, similarly FTIR-spectra showed characteristic peaks of GO at 1614.09 cm(-1), 1374.93 cm(-1) and 1106.55 cm(-1) and OH vibrations peak at 3377 cm(-1). The GO + MH hydrogel showed broad characteristic IR peak at 3009 cm(-1) which attributed to the cumulative vibrations of O-H and N-H stretching. The microscopic techniques such as scanning electron microscopy (SEM), transmission electron microscopy (TEM), atomic force microscopy (AFM) was also done for characterization of the hydrogel. Zeta potential was also monitored of GO (-42 mV) before and after its gelation with metformin (-4 mV). All biophysical techniques validated the successful synthesis of GO and its conjugation with metformin through hydrogen and electrostatic interactions. The release behaviour of metformin from GO + MH hydrogel (1:10 ratio) was also investigated over a period of 24 h in a simulated pH environment of in-vitro experiments and nearly 66% cumulative release was determined. This data indicates that the effective utilization of synthesized GO + MH hydrogel can be done for therapeutics studies in the in-vitro condition. Toxicity profiling of GO was also done on the HepG2 cell line using MIT assay after 24 h incubation and found out the biocompatible nature of GO even at 100 mu g/ml dose concentration. (C) 2019 Elsevier Ltd. All rights reserved.