title: Controlled immobilization of chondroitin sulfate in polyacrylic acid networks.
abstract: Novel semi-interpenetrating polymer networks (semi-IPNs) of chondroitin sulfate (ChS) and acrylic acid (AA) were prepared with the aim of obtaining a hydrogel for use as a colon-specific drug carrier. By controlling the concentrations of cross-linking agent, diethylene glycol dimethacrylate (DEGDA), as well as the reaction solvent, high swelling percentages were obtained (approx. 1600%). However, the highest sol percent obtained for these hydrogels was approx. 70%, and most of the chondroitin sulfate remained soluble and could be extracted. Therefore, an alternative approach was adopted: methacrylate-grafted ChS (ChSMA) was synthesized and then co-polymerized with acrylic acid (AA) at a molar ratio of 1:5 with various concentrations of AA. The sol content of these ChSMA-AA hydrogels was reduced to approx. 20%, and the cross-linking densities were almost 100-fold higher than those of the semi-IPNs. FT-IR spectra showed that the H-bonding interactions between ChS and PAA and the spectra of the semi-IPNs were similar to that of PAA itself after sol extraction. In contrast, the FT-IR spectra of ChSMA-AA remained intact after sol extraction. Ketoprofen was used as a model drug to test the sustained release behavior of these hydrogels.
authors.affiliation: Medicinal and Applied Chemistry, College of Life Science, Kaohsiung Medical University, 100 Shih-Chuan 1st Road, Kaohsiung City 807, Taiwan, ROC.
authors.forename: Shih-Jer
authors.initials: SJ
authors.lastname: Huang
authors.forename: Jin-Ming
authors.initials: JM
authors.lastname: Wang
authors.forename: Sun-Chang
authors.initials: SC
authors.lastname: Tseng
authors.forename: Li-Fang
authors.initials: LF
authors.lastname: Wang
authors.forename: Jenn-Shing
authors.initials: JS
authors.lastname: Chen
mesh_terms: D000180:Acrylic Resins / Q000737:chemistry*; D002809:Chondroitin Sulfates / Q000737:chemistry*; D004337:Drug Carriers / Q000737:chemistry*; D020100:Hydrogels; D006860:Hydrogen Bonding; D007660:Ketoprofen / Q000737:chemistry; D017550:Spectroscopy, Fourier Transform Infrared
chemical_list: D000180:Acrylic Resins; D004337:Drug Carriers; D020100:Hydrogels; C006903:carbopol 940; D002809:Chondroitin Sulfates; D007660:Ketoprofen