Absorbent Polyvinyl Alcohol-Sodium Carboxymethyl Cellulose Hydrogels for Propolis Delivery in Wound Healing Applications

Second degree burns require dressings to heal. The ideal dressing should keep a moist environment, have low cost, be elastic and have a bactericidal effect. The potential of PVA-NaCMC (sodium carboxymethyl cellulose) gels to combine the mechanical and swelling properties of PVA with the flexibility and high water uptake of NaCMC and the antimicrobial characteristics of propolis is investigated. The freeze-thawed gels were characterized by FTIR and DSC. Their swelling behavior, their mechanical response, the delivery of active compounds and their antimicrobial properties were also determined. The main findings of the FTIR analysis were that no chemical bonding occurred between the materials. The DSC analysis revealed that the addition of NaCMC to PVA lowered the PVA crystallinity, as did the addition of propolis, leading to a more deformable gel (as can be observed from the tensile tests results). This also resulted in a higher rate of delivery of active compounds, higher weight loss and higher fluid uptake than comparable PVA-propolis systems, as shown by the swelling tests and by the propolis delivery tests. Samples with 15% propolis content or more inhibited S. aureus colonies with 80% reduction, and are therefore highly absorbent and compliant antimicrobial gels for wound healing. (C) 2017 Society of Plastics Engineers