title: In vitro drug release behavior from a novel thermosensitive composite hydrogel based on Pluronic f127 and poly(ethylene glycol)-poly(epsilon-caprolactone)-poly(ethylene glycol) copolymer.
abstract: BACKGROUND
  Most conventional methods for delivering chemotherapeutic agents fail to achieve therapeutic concentrations of drugs, despite reaching toxic systemic levels. Novel controlled drug delivery systems are designed to deliver drugs at predetermined rates for predefined periods at the target organ and overcome the shortcomings of conventional drug formulations therefore could diminish the side effects and improve the life quality of the patients. Thus, a suitable controlled drug delivery system is extremely important for chemotherapy.
  
  
  RESULTS
  A novel biodegradable thermosensitive composite hydrogel, based on poly(ethylene glycol)-poly(epsilon-caprolactone)-poly(ethylene glycol) (PEG-PCL-PEG, PECE) and Pluronic F127 copolymer, was successfully prepared in this work, which underwent thermosensitive sol-gel-sol transition. And it was flowing sol at ambient temperature but became non-flowing gel at body temperature. By varying the composition, sol-gel-sol transition and in vitro drug release behavior of the composite hydrogel could be adjusted. Cytotoxicity of the composite hydrogel was conducted by cell viability assay using human HEK293 cells. The 293 cell viability of composite hydrogel copolymers were yet higher than 71.4%, even when the input copolymers were 500 microg per well. Vitamin B12 (VB12), honokiol (HK), and bovine serum albumin (BSA) were used as model drugs to investigate the in vitro release behavior of hydrophilic small molecular drug, hydrophobic small molecular drug, and protein drug from the composite hydrogel respectively. All the above-mentioned drugs in this work could be released slowly from composite hydrogel in an extended period. Chemical composition of composite hydrogel, initial drug loading, and hydrogel concentration substantially affected the drug release behavior. The higher Pluronic F127 content, lower initial drug loading amount, or lower hydrogel concentration resulted in higher cumulative release rate.
  
  
  CONCLUSIONS
  The results showed that composite hydrogel prepared in this paper were biocompatible with low cell cytotoxicity, and the drugs in this work could be released slowly from composite hydrogel in an extended period, which suggested that the composite hydrogel might have great potential applications in biomedical fields.
authors.affiliation: State Key Laboratory of Biotherapy, West China Hospital, West China Medical School, Sichuan University, Chengdu, 610041, PR China. chygong14@yahoo.com.cn
authors.forename: Chang Yang
authors.initials: CY
authors.lastname: Gong
authors.forename: Shuai
authors.initials: S
authors.lastname: Shi
authors.forename: Peng Wei
authors.initials: PW
authors.lastname: Dong
authors.forename: Xiu Ling
authors.initials: XL
authors.lastname: Zheng
authors.forename: Shao Zhi
authors.initials: SZ
authors.lastname: Fu
authors.forename: Gang
authors.initials: G
authors.lastname: Guo
authors.forename: Jing Liang
authors.initials: JL
authors.lastname: Yang
authors.forename: Yu Quan
authors.initials: YQ
authors.lastname: Wei
authors.forename: Zhi Yong
authors.initials: ZY
authors.lastname: Qian
mesh_terms: D001672:Biocompatible Materials / Q000493:pharmacokinetics*; D001713:Biphenyl Compounds / Q000493:pharmacokinetics; D002460:Cell Line; D002470:Cell Survival; D016503:Drug Delivery Systems; D006801:Humans; D020100:Hydrogels / Q000493:pharmacokinetics*; D017705:Lignans / Q000493:pharmacokinetics; D020442:Poloxamer / Q000494:pharmacology*; D011091:Polyesters / Q000493:pharmacokinetics*; D011092:Polyethylene Glycols / Q000493:pharmacokinetics*; D013696:Temperature; D014805:Vitamin B 12 / Q000493:pharmacokinetics; D000498:Allyl Compounds; D010636:Phenols
chemical_list: D001672:Biocompatible Materials; D001713:Biphenyl Compounds; D020100:Hydrogels; D017705:Lignans; D020442:Poloxamer; D011091:Polyesters; D011092:Polyethylene Glycols; D014805:Vitamin B 12; C502908:poly(ethylene glycol)-poly(caprolactone)-poly(ethylene glycol); C005499:honokiol; D000498:Allyl Compounds; D010636:Phenols