title: Degradation and drug release property of star poly(epsilon-caprolactone)s with dendritic cores.
abstract: A series of star poly(epsilon-caprolactone)s (PCL) with dendritic cores, PAMAM-PCLs, were synthesized through the ring-opening polymerization of epsilon-caprolactone (CL) initiated by poly(amidoamine) dendrimer (PAMAM-OH). By controlling the feed ratio of the macroinitiator PAMAM-OH to the monomer CL, the star polymers with different branch lengths and properties can be obtained. The successful incorporation of PCL sequences onto the PAMAM-OH core was verified by FTIR, 1H NMR, and combined size-exclusion chromatography and multiangle laser light scattering analysis. The in vitro degradation of PAMAM-PCLs was investigated. The results show the hydrolytic degradation rate increases with increasing content of hydrophilic PAMAM-OH core. While the enzymatic degradation rate is affected by two competitive factors, the catalytic effect of Pseudomonas cepacia lipase on the degradation of PCL branches and the hydrophilicity that depends on the polymer composition. Using the PAMAM-PCLs with different molecular weights, the microsphere drug delivery systems with submicron sizes were fabricated using an "ultrasonic assisted precipitation method." The in vitro drug release from these microspheres was investigated.
authors.affiliation: Key Laboratory of Biomedical Polymers of Ministry of Education, Department of Chemistry, Wuhan University, Wuhan 430072, People's Republic of China.
authors.forename: Zhi-Mei
authors.initials: ZM
authors.lastname: Miao
authors.forename: Si-Xue
authors.initials: SX
authors.lastname: Cheng
authors.forename: Xian-Zheng
authors.initials: XZ
authors.lastname: Zhang
authors.forename: Qing-Rong
authors.initials: QR
authors.lastname: Wang
authors.forename: Ren-Xi
authors.initials: RX
authors.lastname: Zhuo
mesh_terms: D001672:Biocompatible Materials / Q000737:chemistry*; D016956:Burkholderia cepacia / Q000201:enzymology; D050091:Dendrimers / Q000737:chemistry; D004337:Drug Carriers / Q000737:chemistry*; D006868:Hydrolysis; D008049:Lipase / Q000737:chemistry; D009682:Magnetic Resonance Spectroscopy; D011091:Polyesters / Q000737:chemistry; D017550:Spectroscopy, Fourier Transform Infrared
chemical_list: D001672:Biocompatible Materials; D050091:Dendrimers; D004337:Drug Carriers; D011091:Polyesters; D008049:Lipase