Production and characterization of alginate bilayer membranes for releasing simvastatin to treat wounds.

This study aims to produce and characterize alginate bilayer membranes composed of single membranes with varying cross-linking degrees to modulate simvastatin release, with potential to be used for wound-dressing. The single-layer and bilayer membranes were characterized by weight, thickness, surface pH, equilibrium-humidity, swelling degree, solubility, infrared spectroscopy (attenuated total reflectance Fourier-transform infrared), scanning electron microscopy, and water vapor transmission. Simvastatin diffusion and release rates were analyzed using Franz's cells; its indirect cytotoxicity was analyzed using human keratinocyte cells. The difference in the cross-linking degree (bottom and top layers) influenced the morphology of the membrane, and consequently its physical barrier properties. An in vitro release study demonstrated that the bilayer membrane could sustain drug-release for longer time as compared to the single-layer membrane, which could be potentially beneficial for long-term treatment of chronic wounds. A cell viability assay showed that simvastatin-loaded alginate membranes could be characterized as noncytotoxic, demonstrating their potential for use in wound-dressing applications.