Evaluation of covalent and supra-molecular interactions in phosphated galacturonic-glucuronic acid for network structure for use in wound dressings

Keeping in view the wound healing properties of sterculia gum (SG) and ceftriaxone in consideration, in the present work, antibiotic drug encapsulated SG and poly(vinylphosphonic acid) [poly(VPA)] based copolymeric hydrogel wound dressings were designed to enhance the wound healing. Copolymers were characterized by FESEM & EDS, AFM, FTIR, 13C NMR, XRD, TGA and biomedical assay of blood compatibility, mucoadhesion and antioxidant properties. AFM analysis revealed 76.5 nm average roughness and XRD analysis showed sharp peaks at 2θ = 21°. FTIR spectrum of copolymer indicated characteristic peaks at 1116 cm−1 due to stretching vibration of P = O groups of poly(VPA) and twin peaks at 985 and 920 cm−1 due to asymmetric and symmetric vibration of P-O respectively and depicted grafting of phosphated polymers onto gum. The hemolysis test (hemolysis index = 3.40 ± 0.18%) revealed biocompatible nature and the adhesion test demonstrated 84 ± 5.00 mN detachment force which was required to detach the copolymer from the mucosal membrane. Hydrogel dressings absorbed 6.0 ± 5.00 (g/g gel) simulated wound fluid to main the moist wound environment. They were found permeable to O2 and impermeable to microbes and also exhibited antioxidant character. The release profile of ceftriaxone elucidated sustained release of encapsulated ceftriaxone drug with non-Fickian diffusion mechanism and was best fitted in first order kinetic model. Covalent and supra-molecular interactions formed in phosphated galacturonic-glucuronic acid of sterculia gum (SG) were found useful for sustained drug delivery and mucoadhesive properties. These biophysical interactions demonstrated the suitability of antibiotic-encapsulated network structures for wound dressing applications.