Materials, Methods & Technologies, Volume 12, 2018

Abstract: Hydrogels are attractive controlled delivery systems of drugs due to higher surface to volume ratio compared to macroscopic systems. In the scope of the presented work, PEG-DA based spherical hydrogels were synthesized, characterized, and. in vitro controlled release kinetics of the drug from microspheres for different PEG-DA and photoinitiator ratios were investigated with various mathematical models. In the first part of the work, synthesis of PEG-DA based spherical hydrogels by free-radical photopolymerization method by using photoinitiator was done. Polyethylene glycol diacrylate (PEG-DA) was used as macromer, ethylene glycol dimetacrylate (EGDMA) and 2,2 dimetoxy-2 phenylacetophenon (DMPA) were used as cross-linking agent and photoinitiator, respectively. In order to observe the effects of the amounts of the compounds, the ratios of the macromers was tested at 30 and 50 % by weight and photoinitiator ratio was arranged as 0.5 and 1 % by weight while cross-linker ratio was kept constant as 1 % by weight. The chemical characterizations of hydrogel were performed with ATR-FTIR (Attenuated Total Reflectance-Fourier Transform Infrared Spectroscopy) spectrums of hydrogels synthesized in the disc form with the same compositions and the characteristic pikes of PEG-DA was observed. Optic microscope images of synthesized, microspheres were taken. Then drug release experiments of polymer spherical hydrogels with known weight and gentamicin amount, were performed in pH 7 and pH 2 buffer solutions with certain ionic strengths. The drug release kinetic models, zero order, first order, second order, Hixson-Crowell, Weibull, Higuchi, Baker-Lonsdale, and Korsmeyer-Peppas mathematical models were selected. The data were arranged for each hydrogel group according to mathematical models from the graphical change of drug delivery results obtained with time. The mathematical models with highest regression coefficients, in other words the most suitable models for in vitro controlled drug release from PEGDA microspheres were predicted using MATLAB program.