title: The relation between swelling properties and cross-linking of hydrogels designed for colon-specific drug delivery.
abstract: Copolymers of 2-hydroxyethyl methacrylate (HEMA) and methacrylic acid (MAA)-based hydrogels containing 5% and 10% of a cross-linking agent were studied as drug delivery systems. Terephthalic acid was covalently linked with HEMA, abbreviated as CA (cross-linking agent). Free radical cross-linking copolymerization of HEMA and methacrylic acid (MAA) in three different molar ratios, mixed with a particulate 3, 3-azobis (6-hydroxy benzoic acid) (ABHB) as an azo derivative of 5-aminosalicylic acid with the various ratios CA as cross-linking agent were carried out with using 2, 2, Azobisisobutyronitrile as initiator at the temperature range 60-70 degrees C. The compositions of the cross-linked three-dimensional polymers were determined by FTIR spectroscopy. Glass transition temperature of the network polymers was determined calorimetrically. The hydrolysis of drug-polymer conjugates was carried out in cellophane membrane dialysis bags containing an aqueous buffer solution (pH 7.4 and pH 1) at 37 degrees C. The drug-release profiles indicate that the amount of drug release depends on its degree of swelling and cross-linking.
authors.affiliation: Chemistry Department, Faculty of Science, Azarbaijan University of Tarbiat Moallem, Tabriz, Iran. mmahkam@yahoo.com
authors.forename: Mehrdad
authors.initials: M
authors.lastname: Mahkam
authors.forename: Leila
authors.initials: L
authors.lastname: Doostie
mesh_terms: D001391:Azo Compounds / Q000737:chemistry; D002152:Calorimetry, Differential Scanning; D003106:Colon / Q000187:drug effects / Q000378:metabolism; D003432:Cross-Linking Reagents / Q000737:chemistry; D016503:Drug Delivery Systems; D015195:Drug Design; D005609:Free Radicals / Q000737:chemistry; D006801:Humans; D020100:Hydrogels / Q000008:administration & dosage* / Q000138:chemical synthesis; D006863:Hydrogen-Ion Concentration; D019804:Mesalamine / Q000737:chemistry; D008689:Methacrylates / Q000008:administration & dosage / Q000737:chemistry; D011109:Polymethacrylic Acids / Q000008:administration & dosage* / Q000138:chemical synthesis; D012995:Solubility; D013696:Temperature
chemical_list: D001391:Azo Compounds; D003432:Cross-Linking Reagents; D005609:Free Radicals; D020100:Hydrogels; D008689:Methacrylates; D011109:Polymethacrylic Acids; D019804:Mesalamine; C005044:hydroxyethyl methacrylate