HYDROGEL BASED WOUND DRESSING MATERIAL

Abstract

Weak mechanical strength of hydrogels in wet condition limits their use for load bearing applications. Their mechanical strength can be raised by grafting them over some support or by converting them into nanofibrous form. Present thesis is focused on the preparation of poly (acrylamide-co-acrylic acid) hydrogel grafted over cotton fabric using two different cross-linkers i.e. PEG and MBAAm for making medicated dressing and nanofibers of hydrogel of poly (acrylamide-co-acrylic acid). FTIR was used to confirm the insertion of cross-links into the polymer chains. Grafting of uniform hydrogel layer on cotton surface and formation of hydrogel nanofibers were confirmed by using SEM. The average fibre diameter was found to be 275±94.5 nm. Swelling of composite prepared using PEG followed first-order kinetic model at acidic and neutral pH whereas second-order kinetic model at pH 8.5 while that prepared using MBAAm followed second-order kinetic equation at all the pHs studied. The kinetics of swelling was also governed by Peppas model at all pHs. Release of drug from both the composites was studied in phosphate buffers having pH 5.5,7 and 8.5 at 37±0.1°C and observed that it was fastest in phosphate buffer having pH 7. On fitting drug release data into different models, it was observed that drug release was diffusion controlled and followed Fickian diffusion mechanism in case of composite prepared by using PEG as cross-linker whereas it was controlled by diffusion as well as chain relaxation in case of composite prepared by using MBAAm. Mechanical testing using Universal Testing Machine supported a higher mechanical strength of the hydrogel composite as compared to its film. Swelling behaviour of Nanofibrous mats was found to be highest at neutral pH and it followed second order kinetics at all pHs. The drug release kinetics was further evaluated and found that it took place by Fickian diffusion (n < 0.5) and followed second order release kinetics. Antimicrobial tests were performed to show the effectiveness of drug loaded within the hydrogel samples.