title: In vitro degradation and controlled release behavior of D,L-PLGA50 and PCL-b-D,L-PLGA50 copolymer microspheres.
abstract: Blank and bovine serum albumin (BSA)-loaded microspheres based on poly(lactic-acid-alt-glycolic acid) (D,L-PLGA50) and poly(epsilon-caprolactone)-b-poly(lactic-acid-alt-glycolic acid) (PCL-b-D,L-PLGA50) were successfully fabricated using water-in-oil-in-water (w/o/w) double-emulsion extraction/evaporation technique. In vitro degradation of the blank microspheres was characterized by techniques including nuclear magnetic resonance (1H NMR), gel permeation chromatography (GPC), differential scanning calorimetry (DSC) and scanning electron microscopy (SEM). The PCL-b-D,L-PLGA50 copolymer (Mn: number-average molecular weight, Mw: weight-average molecular weight, Mn=44800, Mw/Mn=MWD=1.24, epsilon-caprolactone (CL) %=20.4% in molar ratio) had similar rate of molecular weight reduction compared with the D,L-PLGA50 copolymer before 5 weeks of in vitro degradation. The BSA % loading efficiency of microspheres was mainly controlled by both block copolymer composition and macromolecular architecture, while the sequence structure and the molecular weight of copolymer had no apparent effect on it. Significantly, The PCL-b-D,L-PLGA50 copolymer microspheres showed good release profiles with a nearly constant release during 20-110 days.
authors: Department of Polymer Science and Engineering, School of Chemistry and Chemical Technology, Shanghai Jiao Tong University, Shanghai 200240, PR China. cmdong@sjtu.edu.cn
authors: Chang-Ming
authors: CM
authors: Dong
authors: Ying-Zhi
authors: YZ
authors: Guo
authors: Kun-Yuan
authors: KY
authors: Qiu
authors: Zhong-Wei
authors: ZW
authors: Gu
authors: Xin-De
authors: XD
authors: Feng
mesh_terms: D000818:Animals; D002152:Calorimetry, Differential Scanning; D002417:Cattle; D002850:Chromatography, Gel; D003692:Delayed-Action Preparations / Q000737:chemistry / Q000378:metabolism*; D066298:In Vitro Techniques; D019344:Lactic Acid / Q000737:chemistry / Q000378:metabolism*; D009682:Magnetic Resonance Spectroscopy; D008855:Microscopy, Electron, Scanning; D008863:Microspheres; D008970:Molecular Weight; D011100:Polyglycolic Acid / Q000737:chemistry / Q000378:metabolism*; D011108:Polymers / Q000737:chemistry / Q000378:metabolism*; D012710:Serum Albumin, Bovine / Q000378:metabolism; D013696:Temperature; D013997:Time Factors
chemical_list: D003692:Delayed-Action Preparations; D011108:Polymers; D011100:Polyglycolic Acid; D012710:Serum Albumin, Bovine; D019344:Lactic Acid