Synthesis of carbon-based polyvinyl alcohol composite hydrogels and investigation of it's usability in controlled drug release application

In this study, carbon doped polyvinyl alcohol (PVA) composite hydrogel films using commercial activated carbon (TAC) and multi-walled carbon nanotube (MWCNT) as carbon additives were synthesised in the presence of suitable biocompatible dispersant and their usability in drug delivery applications was investigated. Firstly, carbon additives were modified by thermal stress at high temperature to obtain materials with different surface properties. After modification, a high production yield of 45.9±12.2% was obtained with TAC, while a low production yield of 14.6±7.3% was achieved with MWCNT. The modified carbon additives were characterised by Brunauer-Emmett-Teller (BET) surface area, X-ray diffraction (XRD), Energy Dispersive X-Ray Spectrometry (SEM-EDS) and Fouirer Transform Infrared Spectrophotometry (FTIR) analysis. The results showed that the high temperature thermal stress treatment increased the BET surface area of the carbon additives as well as affecting the porosity, resulting in an increase in the total pore volume. In the continuation of the study, the effect of the use of biocompatible dispersants such as dimethyl sulphoxide (DMSO) and sodium dodecyl sulphate (SDS) on the preparation of carbon doped PVA composite hydrogel films by F/T technique was investigated. For this purpose, DMSO and SDS biocompatible dispersants were added to the synthesis medium and carbon doped composite hydrogel films were prepared by F/T technique. The swelling behaviour, water retention capacity, thickness, direct and indirect energy band gaps of the films were determined. According to these results, it was determined that the use of SDS in the preparation of carbon doped PVA composite hydrogel films by F/T technique prevents agglomeration of carbon dopant in the films. PVA composite hydrogel films containing 25 mg TAC/Mod.TAC and 50 mg MWCNT/Mod.MWCNT were found to be the most suitable hydrogels for drug release studies with better morphological properties with homogeneous distribution of carbon additives throughout the polymeric composite matrix. Salicylic acid (SA) release was investigated as a model drug. The Higuchi release kinetic model was well fitted to determine the release mechanism of SA from carbon doped PVA composite hydrogel films.