Polyvinyl alcohol–glycine composite membranes: preparation, characterization, drug release and cytocompatibility studies

The purpose of this study was to prepare a polyvinyl alcohol–glycine composite membrane to deliver glycine directly to a site of injury to be utilized for the synthesis of collagen for complete healing of a wound. Polyvinyl alcohol (PVA) and glycine (Gly) blended composite membranes, with different PVA:glycine ratios (1:0.2, 1:0.4, 1:0.6, 1:0.8 and 1:1 w/w), were prepared using a conventional solution casting technique. Various characterizations namely XRD, DSC, tensile tests and glycine release studies of the membranes were done. MTT assay was done to ensure cytocompatibility of the PVA–Gly (1:0.6) membrane using L929 fibroblast cells and mice splenocytes. XRD study indicated dispersion of crystalline glycine in a relatively less crystalline PVA in the membrane. FTIR spectra showed shifting of the hydroxyl peak of PVA from 3430 cm−1 to 3171 cm−1 and 3010 cm−1 in the membranes, indicating intermolecular hydrogen bonding and viscosity measurements of various mixtures of PVA–Gly in solution also supported the same. DSC indicated no interaction between PVA and Gly. It was found that the tensile strength of the composite membrane decreased with the increase in glycine content though there was a marginal increase in the strength when the PVA:Gly ratio was 1:1. Further increase in the Gly content in the membranes was not possible as a solid physical gel was formed while mixing the solutions of PVA and Gly. Gly release from the membrane was immediate following diffusion-controlled Fickian kinetics. The relative cell proliferation of the L929 cells and mice splenocytes were found to be 2.38 and 2.24, respectively, indicating the cytocompatibility of the membrane.