Curcumin-incorporated crosslinked sodium alginate-g-poly (N-isopropyl acrylamide) thermo-responsive hydrogel as an in-situ forming injectable dressing for wound healing: In vitro characterization and in vivo evaluation

Sodium alginate products have been extensively used for wound-dressing. In present study, a series of thermo-sensitive cross-linked poly(N-isopropylacrylamide) grafted sodium alginate (Alg-g-pNIPAM) copolymers were synthesized for delivery of curcumin to wound. FTIR, H-1 NMR, elemental analysis and DSC showed successful polymerization and precise structure of copolymers. Thermogelation at 27-42 degrees C depending on the copolymer concentration, chain-length of pNIPAM and pH was observed. The optimum copolymer with proper rheological and syringeability properties showed excellent thermogelling at a wide range of pH and concentration, and could prolong the release of curcumin up to 72 h. In-vivo wound contraction and histopathological evaluations revealed that in addition to the higher efficacy in wound contraction, the curcumin formulation (Cur-F) significantly reduced the inflammation, enhanced the collagenesis and resulted in increased number of fibro-blasts. Well-known anti-oxidant and anti-inflammatory properties of curcumin and in situ-forming nature of Alg-g-pNIPAM can make the system an excellent candidate for further investigations.