title: Biodegradable thermogelling hydrogel of P(CL-GL)-PEG-P(CL-GL) triblock copolymer: degradation and drug release behavior.
abstract: Degradation and drug release behavior of thermogelling hydrogel of poly(epsilon-caprolactone-co-glycolide)-poly(ethylene glycol)-poly(epsilon-caprolactone-co-glycolide) [P(CL-GL)-PEG-P(CL-GL) (1880-1540-1880)] triblock copolymer were investigated. The copolymer aqueous solution (25 wt%) underwent sol-gel transition at 35 degrees C as the temperature increased and formed a stable gel at body temperature. After incubation in PBS buffer solution (0.1 M) at 37 degrees C, the gel degraded completely into a viscous liquid at 14th week. Chemical microstructural analysis of the degraded samples by (1)H-NMR revealed the degradation occurring mainly on the glycolyl sequences of the copolymer. The pH value of the gel buffer solution maintained neutral during the initial 8 weeks, which may be beneficial for the preservation of activity of pH-sensitive drugs. Incorporation of drugs into the gel was formulated at room temperature without the use of any organic solvent. The gel formed a controlled release depot with delivery times of 12, 32, and 25 days for isoniazid, rifampicin and bovine serum albumin, respectively. Controlled release of hydrophobic rifampicin was achieved with insignificant burst effect due to the distribution of the drug mainly in the hydrophobic polyester regions of the gel.
authors.affiliation: Chengdu Institute of Organic Chemistry, Chinese Academy of Sciences, P.O. Box 415, Chengdu 610041, China.
authors.forename: Zhiqiang
authors.initials: Z
authors.lastname: Jiang
authors.forename: Jianyuan
authors.initials: J
authors.lastname: Hao
authors.forename: Yujing
authors.initials: Y
authors.lastname: You
authors.forename: Qun
authors.initials: Q
authors.lastname: Gu
authors.forename: Weiming
authors.initials: W
authors.lastname: Cao
authors.forename: Xianmo
authors.initials: X
authors.lastname: Deng
mesh_terms: D000818:Animals; D001672:Biocompatible Materials / Q000737:chemistry / Q000378:metabolism*; D002417:Cattle; D003692:Delayed-Action Preparations / Q000737:chemistry / Q000378:metabolism; D004146:Dioxanes / Q000737:chemistry / Q000378:metabolism*; D016503:Drug Delivery Systems / Q000379:methods; D005026:Ethylene Glycols / Q000737:chemistry / Q000378:metabolism*; D020100:Hydrogels / Q000737:chemistry / Q000378:metabolism*; D011091:Polyesters / Q000737:chemistry / Q000378:metabolism*; D011108:Polymers / Q000737:chemistry / Q000378:metabolism
chemical_list: D001672:Biocompatible Materials; D003692:Delayed-Action Preparations; D004146:Dioxanes; D005026:Ethylene Glycols; D020100:Hydrogels; D011091:Polyesters; D011108:Polymers; C476300:poly(epsilon-caprolactone)-b-poly(ethylene glycol); C095495:glycolide E-caprolactone copolymer