Design of polysaccharide gum based network copolymeric hydrogels for drug delivery and wound dressing applications

This article deals with the exploration of the design of network crosslinked structure by covalent bonding for use as wound dressing materials keeping in view inherent therapeutic role of neem gum in wound healing.These copolymeric hydrogels were prepared by graft-copolymerization reaction of carbopol and poly(N-vinylpyrrolidone)(poly(NVP).Antibiotic drug levofloxacin was encapsulated in dressings for better wound healing.The scanning electron microscopy(SEM),atomic force microscopy(AFM),Fourier transform infrared(FTIR)spectroscopy,^(13)C nuclear magnetic resonance(NMR)spectroscopy,X-ray diffraction(XRD),thermogravimetric analysis(TGA),differential thermal gravimetry(DTG),and differential scanning calorimetry(DSC)techniques were applied for characterization.NMR and FTIR demonstrated incorporation of carbapol and poly(NVP)in dressings.XRD indicated amorphous state in copolymeric dressings.Interactions of copolymers with drug,blood and bio membrane were studied to evaluate biomedical properties which revealed controlled release of drug from hydrogel dressings which were possessing blood-compatible(haemolytic value=2.4±0.82)and mucoadhesive(detachment force=124±41 mN)properties.Dressings were permeable to O2 and H2O vapour and absorbed 6.68±±0.62 g/g wound fluid which is ideal dressing characteristic.Diffusion mechanism type of drug levofloxacin was Fickian with kinetic model First order.These properties suggested use of hydrogel material for wound dressing and drug delivery applications for better wound care management.This article deals with the exploration of the design of network crosslinked structure by covalent bonding for use as wound dressing materials keeping in view inherent therapeutic role of neem gum in wound healing.These copolymeric hydrogels were prepared by graft-copolymerization reaction of carbopol and poly(N-vinylpyrrolidone)(poly(NVP).Antibiotic drug levofloxacin was encapsulated in dressings for better wound healing.The scanning electron microscopy(SEM),atomic force microscopy(AFM),Fourier transform infrared(FTIR)spectroscopy,13C nuclear magnetic resonance(NMR)spectroscopy,X-ray diffraction(XRD),thermogravimetric analysis(TGA),differential thermal gravimetry(DTG),and differential scanning calorimetry(DSC)techniques were applied for characterization.NMR and FTIR demonstrated incorporation of carbapol and poly(NVP)in dressings.XRD indicated amorphous state in copolymeric dressings.Interactions of copolymers with drug,blood and bio membrane were studied to evaluate biomedical properties which revealed controlled release of drug from hydrogel dressings which were possessing blood-compatible(haemolytic value=2.45±.82)and mucoadhesive(detachment force=124±41 mN)properties.Dressings were permeable to O2 and H_(2)O vapour and absorbed 6.68±0.62 g/g wound fluid which is ideal dressing characteristic.Diffusion mechanism type of drug levofloxacin was Fickian with kinetic model First order.These properties suggested use of hydrogel material for wound dressing and drug delivery applications for better wound care management.

Preparation of amphiphilic graft copolymer with polyisoprene backbone by combination of anionic polymerization and "click" reaction

A novel graft copolymer consisting of polyisoprene backbone and hydrophilic side chain with carbamic acid ester functional group was prepared via thiol-ene＂click＂reaction and alcohol-isocyanate reactions.Polyisoprene was synthesized by anionic polymerization using n-butyl lithium as initiator,and the pendant hydroxyl groups were introduced by the thiol-ene reaction of mercaptoethanol with the double bond of 1,2-addition units of PI backbone in the presence of radical initiator azobisisobutyronitrile. Isocyanate end group capped poly（ethylene glycol）（mPEG-NCO） was grafted onto the PI backbone through alcoholisocyanate reaction between the pendant hydroxyl groups and isocyanate group of mPEG-NCO.The structure of the graft copolymer were characterized and confirmed by means of size-exclusion chromatography,~1H NMR and FTIR spectroscopy.