title: Microwave-assisted synthesis of poly(epsilon-caprolactone)-poly(ethylene glycol)-poly(epsilon-caprolactone) tri-block co-polymers and use as matrices for sustained delivery of ibuprofen taken as model drug.
abstract: Poly(epsilon-caprolactone)-poly(ethylene glycol)-poly(epsilon-caprolactone) triblock co-polymers with number-average molar mass (Mn) over 20000 g/mol were prepared by ring-opening polymerization of epsilon-caprolactone initiated by poly(ethylene glycol) under microwave irradiation. This method was proposed as a means to improve in vivo compatibility as no harmful chemicals were involved in the polymerization except epsilon-caprolactone and poly(ethylene glycol). The resulting tri-block co-polymers were characterized by FT-IR, H-NMR, GPC and WAXD. Their Mn and their composition was controlled by the amount and the chain length of the poly(ethylene glycol) macromers involved in the feed. The ability of poly(epsilon-caprolactone)-poly(ethylene glycol)-poly(epsilon-caprolactone) co-polymers to entrap and deliver drugs was investigated with ibuprofen as a model drug. The release of ibuprofen was significantly influenced by the co-polymer composition and the extent of loading. The in vitro release of ibuprofen was sustained from 3 to 15 days for 10% loading, depending on the ratio of epsilon-caprolactone to ethylene glycol-derived subunits in co-polymer chains. This ratio ranged from 0.97 to 9.78. In the case of the co-polymer whose epsilon-caprolactone molar ratio to ethylene glycol-derived subunits was 2.49, the ibuprofen release was sustained for 2 to 24 days for ibuprofen loads going from 5 to 20 wt%.
authors.affiliation: Department of Polymer Science, College of Chemistry and Molecular Science, Wuhan University, Wuhan 430072, P R. China.
authors.forename: Zhaoju
authors.initials: Z
authors.lastname: Yu
authors.forename: Lijian
authors.initials: L
authors.lastname: Liu
mesh_terms: D016503:Drug Delivery Systems / Q000295:instrumentation* / Q000379:methods*; D007052:Ibuprofen / Q000008:administration & dosage / Q000378:metabolism*; D009682:Magnetic Resonance Spectroscopy; D008872:Microwaves; D015394:Molecular Structure; D011091:Polyesters / Q000138:chemical synthesis* / Q000737:chemistry*; D011092:Polyethylene Glycols / Q000138:chemical synthesis* / Q000737:chemistry*; D011108:Polymers / Q000138:chemical synthesis* / Q000737:chemistry*; D017550:Spectroscopy, Fourier Transform Infrared
chemical_list: D011091:Polyesters; D011108:Polymers; C492324:poly(epsilon-caprolactone)-poly(oxyethylene)-poly(epsilon-caprolactone); D011092:Polyethylene Glycols; D007052:Ibuprofen