beta-Cyclodextrin hydrogels containing naphthaleneacetic acid for pH-sensitive release.
beta-Cyclodextrin (beta-CD) hydrogel was prepared in a strong alkali condition using epichlorohydrin (EPI) as a cross-linker, where the molar ratios of EPI to beta-CD were 8:1, 10:1, and 15:1. In order to endow a pH sensitivity to the hydrogel, naphthaleneacetic acid (NAA) was loaded in the hydrogel by taking advantage of its hydrophobic interaction with the cavities of beta-CD. The releases of blue dextran (a water-soluble dye) from the hydrogels were promoted, as the pHs of the media increased. When the molar ratio of EPI to beta-CD was lower, the degrees of release were higher, and the pH dependency of the release became more prominent. In fact, the swelling ratio of the hydrogels having a lower molar ratio of EPI to beta-CD was higher. The higher swelling ratio would account for the higher degree of release and the marked pH sensitivity.
School of Biotechnology & Bioengineering, Institute of Bioscience and Biotechnology, Kangwon National University, 192-1, Hyoja 2 dong, Chunchon, Kangwon-do 200-701, Korea.
Xia
X
Yang
Jin-Chul
JC
Kim
D000042:Absorption; D003692:Delayed-Action Preparations / Q000737:chemistry*; D004058:Diffusion; D020100:Hydrogels / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D008422:Materials Testing; D009280:Naphthaleneacetic Acids / Q000737:chemistry*; D009997:Osmotic Pressure; D047392:beta-Cyclodextrins / Q000008:administration & dosage / Q000737:chemistry*
D003692:Delayed-Action Preparations; D020100:Hydrogels; D009280:Naphthaleneacetic Acids; D047392:beta-Cyclodextrins; C031215:betadex