Drug release kinetics of pH‐responsive microgels of different glass‐transition temperatures

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.

Surface‐Bound Microgels for Separation, Sensing, and Biomedical Applications

“…Common synthetic monomers found in synthetic bioactive systems include Am, NIPAm, AA, butyl acrylate, caprolactone, and phenylboronic acid. [152][153][154][155] Xia et al utilized the thermo-responsive swelling of PNIPAm-based microgel coatings to recover sheets of cells with over 90% efficiency successfully. [156] Reducing the temperature from 37 to 20 °C detached previously bound COS7 and L929 fibroblast cells from the microgel coating.…”