title: Drug release kinetics and transport mechanisms from semi-interpenetrating networks of gelatin and poly(ethylene glycol) diacrylate.
abstract: OBJECTIVE
  To elucidate the key parameters affecting solute transport from semi-interpenetrating networks (sIPNs) comprised of poly(ethylene glycol) diacrylate (PEGdA) and gelatin that are partially crosslinked, water-swellable and biodegradable. Effects of material compositions, solute size, solubility, and loading density have been investigated.
  
  
  METHODS
  sIPNs of following gelatin/PEGdA weight-to-weight ratios were prepared: 10:15, 10:20, 10:30, 15:15, 20:15. Five model solutes of different physicochemical properties were selected, i.e. silver sulfadiazine (AgSD), bupivacaine hydrochloride (Bup), sulfadiazine sodium (NaSD), keratinocyte growth factor (KGF), and bovine serum albumin conjugated with fluorescein isothiocyanate (BSA-FITC). Release studies were performed and the results were analyzed using three hydrogel based common theories (free volume, hydrodynamic and obstruction).
  
  
  RESULTS
  The release kinetics of model solutes was influenced by each factor under investigation. Specifically, the initial release rates and intra-gel diffusivity decreased with increasing PEGdA content or increasing solute molecular weight. However, the initial release rate and intra-gel diffusivity increased with increasing gelatin content or increasing solute water solubility, which contradicted with the classical hydrogel based solute transport theories, i.e. increasing polymer volume leads to decreased solute diffusivity within the gel.
  
  
  CONCLUSIONS
  This analysis provides structure-functional information of the sIPN as a potential therapeutic delivery matrix.
authors: School of Pharmacy, University of Wisconsin-Madison, Madison, WI 53705, USA.
authors: Yao
authors: Y
authors: Fu
authors: Weiyuan John
authors: WJ
authors: Kao
mesh_terms: D002045:Bupivacaine / Q000493:pharmacokinetics; D002851:Chromatography, High Pressure Liquid; D051523:Fibroblast Growth Factor 7 / Q000493:pharmacokinetics; D005780:Gelatin / Q000493:pharmacokinetics*; D011092:Polyethylene Glycols / Q000493:pharmacokinetics*; D012710:Serum Albumin, Bovine / Q000493:pharmacokinetics; D012837:Silver Sulfadiazine / Q000493:pharmacokinetics; D013056:Spectrophotometry, Ultraviolet
chemical_list: D051523:Fibroblast Growth Factor 7; D012710:Serum Albumin, Bovine; D011092:Polyethylene Glycols; D005780:Gelatin; D012837:Silver Sulfadiazine; D002045:Bupivacaine