Photocrosslinked poly(ethylen glycol) hydrogels for controlled drug delivery

Objective: In the work presented, synthesis of PEG based hydrogels, characterization of synthesized hydrogels and usage of these hydrogels in controlled drug release systems were studied. Methods: Synthesis of PEG based hydrogels having different properties was done by free radical photopolymerization by using a photoinitiator. In this stage because of their biocompatibility, poly ethylene glycol Diacrylate (PEG-DA) as macromer; ethylene glycol dimetacrylate (EGDMA) as cross-linker and 2,2 dimetoxy-2 phenylacetophenon (DMPA) as photoinitiator were used. The macromer amounts of 30, 50 and 100%, cross-linker ratio of 0.25, 1.0 and 3% and photoinitiator ratio of 0.1, 0.5 and 1% by weight were selected. In this scope, dynamic swelling behaviour of hydrogels and their suitability for controlled drug release were tested. The surface characterization of the hydrogels was performed by Attenuated Total Reflectance-Fourier Transfer Infrared Spectroscopy (ATR-FTIR) spectrums. The drug release experiments of dry polymer disks with known weight and known loaded drug amount were performed in pH 7.4 and 1.2 buffer solutions with set ionic strengths, in shaking incubator at 37 degrees C constant temperature with a shaking speed of 100 rpm. In the last part of the work, drug activities of synthesized drug-loaded hydrogels were tested in Staphylococcus aureus and Pseudomonas aeruginosa bacteria cultures. Results: A decrease in swelling degree of hydrogel was observed with an increase in macromer ratio. In the ATR-FTIR spectrums, O-H tension, C-H tension, C=O tension, C-O tension vibration bands which can be said to be a characteristic of PEG-DA hydrogels were observed. The rate of drug release in pH 1.2 was observed to be much faster than pH 7.4 for both types of hydrogels. The transport mechanism in hydrogels was determined by a widely used semi-empirical formula. It was observed that selected drug-loaded hydrogels were effective on inhibition of the reproduction of both bacteria. Conclusion: In the work presented, all of the hydrogels synthesized were found compatible for the controlled drug delivery.