Developing 3D-network gels from polysaccharide gums for biomedical applications

Abstract

Keeping in view the recent advancements in polysaccharide materials, gum acacia (GA) - tragacanth gum (TG) was investigated for designing polymeric network structures impregnated with cephalexin antibiotics for drug delivery (DD). Grafted product of polyvinylimidazole [poly(VIm)] and GA-TG was characterized by field emission scanning electron microscopy (FESEM), atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), thermo-gravimetric analysis (TGA) and differential scanning calorimetry (DSC). Change in mesh size (from 17.73 to 32.98 nm) and crosslinking density (between 1.64 × 10−5 to 5.06 × 10−5 mol cm−3) was found with change in poly(VIm), gum and crosslinker NNMBA content which revealed that these parameters can be tailored made as per requirement and applications. Swelling properties illustrated pH sensitivity in copolymers because of composition which is useful for colon or site-specific DD of cephalexin. FESEM and AFM demonstrated heterogeneous morphology with the rough surface topology of grafted product. XPS and FTIR confirmed the grafting of poly(VIm) onto polysaccharide chains. Drug diffusion was non-Fickian and release was fitted in Higuchi kinetic model from copolymers. The release was slow and prolonged due to drug-polymer interactions. Copolymers exhibited 31.29% scavenging ability in DPPH assay and haemolysis was less than 2% that inferred biocompatible nature. Bio-surface interactions with intestinal membrane indicated the muco-adhesive nature of copolymers. Antimicrobial properties of hydrogel were evaluated against E. coli, P. aeruginosa and S. aureus. All observations revealed that GA-TG crosslinked copolymers could be explored for colon DD of antibiotic drugs with tailored crosslinking density.