Polyethylene glycol methacrylate/dimethacrylate hydrogels for controlled release of hydrophobic drugs
DiRamio, Jacqueline Adele
MetadataShow full item record
We report on the release characteristics of a model hydrophobic drug, estradiol, entrapped in polyethylene glycol methacrylate (PEG-MA)/dimethacrylate (PEG-DMA) hydrogels. The crosslinking ratio, temperature, and pH ranged from 10:1 to 10:3, from 33 to 41ºC, and from 2 to 12, respectively. The gelation of the PEG-MA/PEG-DMA hydrogel was initiated with UV-irradiation. The absence of poly(glutamic acid) in the hydrogel formulation resulted in a loss of pH-sensitivity. Use of high molecular weight polymers resulted in higher hydrogel swelling (300%) in comparison to low molecular weight polymers. Drug size was also found to be a significant factor. Based on the release kinetics of the estradiol drug, the hydrogels displayed a non-Fickian diffusion mechanism, which indicated the media penetration rate was in the same range as the drug diffusion. The synthesis, entrapment and release of estradiol by the PEG-MA/PEG-DMA hydrogels proved to be successful, but the use of ethanol in the buffers to promote the hydrophobic drug release caused complications, attributed to transesterification.