title: [Preparation of ibuprofen/sPEG-b-PLLA copolymer microspheres and its in vitro release properties].
abstract: Biodegradable four-arm star-shaped poly(ethylene glycol)-block-poly(L-lactic acid) copolymer (sPEG-b-PLLA), four-arm star-shaped poly(L-lactic acid) (sPLLA), linearly poly(ethylene glycol)-block-poly(L-lactic acid) copolymer (PEG-b-PLLA) and linearly poly(L-lactic acid) (PLLA) were synthesized from L-lactice acid, pentaerythritol, poly(ethylene glycol) and star-shaped poly(ethylene glycol), using the method of melt polycondensation, and the products were characterized and confirmed by 1H NMR spectroscopy, FT-IR and GPC. Four types of ibuprofen loaded microspheres based on the above four types of polymers, i.e., IBU/PLLA, IBU/sPLLA, IBU/PEG-b-PLLA, and IBU/sPEG-b-PLLA microspheres were prepared using the method of solvent evaporation, and the optimized preparation technology was obtained via orthogonal experiments, and the drug-encapsulating properties and in vitro drug-releasing properties were studied. The results showed that compared with IBU/PLLA and IBU/PEG-b-PLLA microspheres, the drug encapsulate efficiency of IBU/sPLLA and IBU/sPEG-b-PLLA microspheres were higher and the in vitro drug releasing rate slowed down, which mainly due to the faster degradation of sPLLA and sPEG-b-PLLA for the star-shaped structure and the block copolymerization of sPEG. The drug releasing curves of these three types of microspheres could be fit by first-order equation, and the releasing mechanism was non-Fickian diffusing, i.e., the synergetic effect of polymer degradation and drug diffusion.
authors.affiliation: Department of Pharmaceutical Engineering, College of Resources and Environment, South China Agriculture University, Guangzhou 510642, China. linyaling@scau.edu.cn
authors.forename: Ya-ling
authors.initials: YL
authors.lastname: Lin
authors.forename: An-qiang
authors.initials: AQ
authors.lastname: Zhang
authors.forename: Fu-yi
authors.initials: FY
authors.lastname: Guan
authors.forename: Yao-dong
authors.initials: YD
authors.lastname: Chen
authors.forename: Wei-an
authors.initials: WA
authors.lastname: Tan
authors.forename: Lian-shi
authors.initials: LS
authors.lastname: Wang
mesh_terms: D018712:Analgesics, Non-Narcotic / Q000008:administration & dosage / Q000737:chemistry; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000008:administration & dosage / Q000737:chemistry; D003692:Delayed-Action Preparations; D004337:Drug Carriers; D007052:Ibuprofen / Q000008:administration & dosage* / Q000737:chemistry; D007773:Lactates / Q000737:chemistry; D019344:Lactic Acid / Q000737:chemistry; D009682:Magnetic Resonance Spectroscopy; D008863:Microspheres; D010316:Particle Size; D011091:Polyesters; D011092:Polyethylene Glycols / Q000737:chemistry; D011108:Polymers / Q000737:chemistry*; D017550:Spectroscopy, Fourier Transform Infrared
chemical_list: D018712:Analgesics, Non-Narcotic; D000894:Anti-Inflammatory Agents, Non-Steroidal; D003692:Delayed-Action Preparations; D004337:Drug Carriers; D007773:Lactates; D011091:Polyesters; D011108:Polymers; C088513:poly(lactic acid-ethylene glycol); D019344:Lactic Acid; D011092:Polyethylene Glycols; C033616:poly(lactide); D007052:Ibuprofen