Synthesis and characterization of poly(2-hydroxyethyl methacrylate/itaconic acid/poly(ethylene glycol) dimethacrylate) hydrogels

Abstract

Hydrogels based on 2-hydroxyethyl methacrylate (HEMA), different poly(ethylene glycol) dimethacrylates (PEGDMA) and itaconic acid (IA) were prepared by free radical crosslinking copolymerization. The influence of different PEGDMA content and type, with PEG chain length of 550 and 875, on the structure, morphology, biocompatibility, swelling and release properties of P(HEMA/IA/550PEGDMA) and P(HEMA/IA/875PEGDMA) copolymeric hydrogels have been investigated. Preliminary biocompatibility characterization of P(HEMA/IA/PEGDMA) hydrogels, done by the cytotoxicity assays using the HeLa cell line, indicated satisfactory cytocompatibility. Swelling studies were conducted for all samples in a physiological pH and temperature range, showing a noticeable pH sensitivity and temperature dependent equilibrium swelling. The characterization by Fourier transform infrared (FTIR) spectroscopy confirmed the presence of all monomers used in the gel structure, and morphology study, performed by scanning electron microscopy (SEM), revealed no significant differences between the samples with respect to pore size. In order to elucidate the release mechanism, drug release study was carried out in vitro using two forms of vitamin 6:3: nicotinamide (NAm) and nicotinic acid (NAc). The dissolution profiles were fitted to various mathematical models and the best fit was obtained for first order kinetics. The favorable swelling and drug release properties of P(HEMA/IA/PEGDMA) hydrogels make them good candidates to be used as biomaterials.