Investigation of the swelling response and drug loading of ionic microgels: The dependence on functional group composition


Journal Article

Spherical micron-sized (4-7 μm diameter) poly(methacrylic acid-co-nitrophenyl acrylate) microgels were synthesized by precipitation polymerization and selectively derivatized with carboxylic acid, glutamic acid, hydroxamic acid, sulfonic acid, and ethanol functional groups in five separate post-polymerization reactions. The pH and NaCl induced swelling response, drug loading, capacity (`capacity' = total number of functional ionic groups that bind protons), and density of the five different composition anionic microgels, each containing a different functional group as well as a baseline of carboxylic acid groups, were measured. Using the micropipet flow technique, it was found that the pH range of the swelling response for the five different microgel compositions shifted by an amount that was proportional to the solution pKa's of their functional groups. The degree of drug loading increased in proportion to the microgels' capacity. However, the drug loading did not decrease proportionately when the capacity was lowered.

Full Text

Duke Authors

Cited Authors

  • Eichenbaum, GM; Kiser, PF; Shah, D; Simon, SA; Needham, D

Published Date

  • December 28, 1999

Published In

Volume / Issue

  • 32 / 26

Start / End Page

  • 8996 - 9006

International Standard Serial Number (ISSN)

  • 0024-9297

Digital Object Identifier (DOI)

  • 10.1021/ma9908393

Citation Source

  • Scopus