Clindamycin releasing bionanocomposite hydrogels as potential wound dressings for the treatment of infected wounds

The bionanocomposite hydrogels based on polyvinyl alcohol and egg white (as the matrix) and montmorillonite nanoclay (as reinforcement) were fabricated via the freezing-thawing technique. The prepared bionanocomposite hydrogels were loaded with clindamycin, as an effective antibiotic, to attain new potential wound dressings for healing the infected wounds. The microstructural properties of the bionanocomposite hydrogel wound dressings were characterized using the X-ray diffractometry, transmission electron microscopy, atomic force microscopy and gel fraction measurement. It was shown that all of the bionanocomposite hydrogel wound dressings had an exfoliated morphology and the montmorillonite layers acted as additional crosslinking zones to interconnect the polyvinyl alcohol and egg white chains. The characteristics of the prepared wound dressings were investigated using different experiments, including the water content, drying, water vapor transmission rate (WVTR), transparency and in vitro drug release tests. It was found that the equilibrium water content and WVTR were tended to decrease by increasing the loading level of montmorillonite in samples. The results showed that the drying period of bionanocomposite hydrogel wound dressings was prolonged by increasing the content of the incorporated montmorillonite. In vitro drug delivery experiments showed the cumulative fractional release of clindamycin and the clindamycin diffusion coefficient were decreased either by increasing the weight percentage of the incorporated montmorillonite into the wound dressings or by decreasing the pH of the release medium. It was also shown that the mechanism governing the release of clindamycin in all examined samples was the non-Fickian (anomalous) transport.