title: Characterization of drug release and diffusion mechanism through hydroxyethylmethacrylate/methacrylic acid pH-sensitive hydrogel.
abstract: Hydroxyethylmethacrylate/methacrylic acid copolymer cross-linked with ethylenglycol dimethacrylate was prepared by a bulk free radical polymerization method. The permeability studies of this pH-sensitive hydrogel to drugs with different water solubilities showed a water-content dependent diffusion or pore mechanism for ephedrine HCl (water-soluble model drug), whereas, a partition or solute-diffusion mechanism for indomethacin (a water-insoluble drug) was seen. Data analysis of release tests, according to the swelling interface number and Peppas equation for ephedrine HCl in pH 7.4, showed a biexponential model kinetic, whereas in pH 1.2 a swelling-controlled mechanism was seen. Indomethacin was released by an anomalous or non-Fickian release kinetics.
authors.affiliation: Department of Pharmaceutics, School of Pharmacy and Pharmaceutical Sciences, Isfahan University of Medical Sciences, Isfahan, Iran. j_varshosaz@hotmail.com
authors.forename: Jaleh
authors.initials: J
authors.lastname: Varshosaz
authors.forename: Mahmood
authors.initials: M
authors.lastname: Hajian
mesh_terms: D002626:Chemistry, Pharmaceutical / Q000295:instrumentation; D004058:Diffusion / Q000187:drug effects*; D016503:Drug Delivery Systems / Q000379:methods*; D004809:Ephedrine / Q000737:chemistry / Q000493:pharmacokinetics; D020100:Hydrogels / Q000737:chemistry / Q000493:pharmacokinetics*; D006863:Hydrogen-Ion Concentration; D007213:Indomethacin / Q000737:chemistry / Q000493:pharmacokinetics; D008689:Methacrylates / Q000737:chemistry / Q000493:pharmacokinetics*; D009570:Nitriles / Q000737:chemistry; D010539:Permeability; D012821:Silanes / Q000737:chemistry / Q000493:pharmacokinetics; D012995:Solubility; D014867:Water
chemical_list: D020100:Hydrogels; D008689:Methacrylates; D009570:Nitriles; D012821:Silanes; D014867:Water; C008384:methacrylic acid; C416211:dichloromethylsilane; C005044:hydroxyethyl methacrylate; C004919:ethylene dimethacrylate; C004526:azobis(isobutyronitrile); D004809:Ephedrine; D007213:Indomethacin