title: Thermosensitive poly(organophosphazene) hydrogels for a controlled drug delivery.
abstract: Thermosensitive poly(organophosphazenes) were synthesized for a controlled release of hydrophilic polymeric model drugs such as dextran and albumin in this study. The solutions of the present polymers bearing both hydrophobic side groups of L-isoleucine ethyl ester (IleOEt) and hydrophilic groups of alpha-amino-omega-methoxy-PEG (Mw 550) (AMPEG550) exhibited reversible sol-gel transition behaviors with changes of temperature. Viscometric measurement indicated that the thermosensitive hydrogels with good strength could be formed from the solutions in the range of the concentrations of 7-15 wt% around body temperature. For increasing their biodegradabililites, depsipeptides of ethyl-2-(O-glycyl)lactate (GlyLacOEt) were also introduced to the polymer, showing enhanced degradation of hydrogels. In vitro release behaviors of hydrophilic FITC-dextran (Mw 71,600) and human serum albumin from these polymer hydrogels were sustained for about 2 weeks while those from poloxamer (Pluronic F-127) hydrogel showed a distinct initial burst. The release of FITC-dextran exhibited concentration-dependent behavior ranging from 7 to 15 wt% of the polymer solution while it was almost independent of the concentration of FITC-dextran.
authors.affiliation: Division of Life Science, Korea Institute of Science and Technology, Seoul, Republic of Korea.
authors.forename: Gyung Don
authors.initials: GD
authors.lastname: Kang
authors.forename: Se Hwa
authors.initials: SH
authors.lastname: Cheon
authors.forename: Gilson
authors.initials: G
authors.lastname: Khang
authors.forename: Soo-Chang
authors.initials: SC
authors.lastname: Song
mesh_terms: D003692:Delayed-Action Preparations / Q000737:chemistry*; D003911:Dextrans / Q000008:administration & dosage / Q000737:chemistry; D016650:Fluorescein-5-isothiocyanate / Q000008:administration & dosage / Q000031:analogs & derivatives / Q000737:chemistry; D006358:Hot Temperature; D020100:Hydrogels / Q000737:chemistry*; D011108:Polymers / Q000737:chemistry*; D012709:Serum Albumin / Q000008:administration & dosage / Q000737:chemistry; D012995:Solubility
chemical_list: D003692:Delayed-Action Preparations; D003911:Dextrans; D020100:Hydrogels; D011108:Polymers; D012709:Serum Albumin; C015219:fluorescein isothiocyanate dextran; D016650:Fluorescein-5-isothiocyanate