Drug release kinetics of pH-responsive microgels of different glass-transition temperatures |
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| Authors: | M S Islam J P K Tan C Y Kwok K C Tam |
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| Affiliation: | 1. Department of Chemical Engineering, Waterloo Institute for Nanotechnology, University of Waterloo, 200 University Avenue West, Waterloo, Ontario N2L 3G1, Canada;2. Institute of Bioengineering and Nanotechnology, Agency for Science and Technology Research, 31 Biopolis Way, The Nanos 138669, Singapore |
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| Abstract: | The pH-responsive microgels (MGs) consisting of methacrylic acid-ethyl acrylate (MAA-EA), methacrylic acid-butyl methacrylate (MAA-BMA) or methacrylic acid-methyl methacrylate (MAA-MMA) crosslinked with di-allyl phthalate (DAP) were synthesized via emulsion polymerization. It was found that the energy required to extract a proton from MGs with higher glass-transition temperature (Tg) was greater than at a lower Tg. Procaine hydrochloride (PrHy) was used to study the release of a model hydrophobic drug from MGs with different Tgs. A drug selective electrode (DSE) was used to monitor the release as a function of pHs and Tgs. With increasing pH or decreasing Tg, the swelling of MGs was enhanced, leading to greater release of the drug. From the Berens and Hopfenberg model, the contributions of chain relaxation and diffusion processes during a release process were determined. The drug release from lower Tg MGs and at high pH is dominated by diffusion rather than chain relaxation. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47284. |
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| Keywords: | Berens and Hopfenberg model drug release drug selective electrode glass transition temperature pH responsive microgels |
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