title: Doxorubicin-loaded PEG-PCL copolymer micelles enhance cytotoxicity and intracellular accumulation of doxorubicin in adriamycin-resistant tumor cells.
abstract: BACKGROUND
  Multidrug resistance remains a major obstacle to successful cancer chemotherapy. Some chemical multidrug resistance inhibitors, such as ciclosporin and verapamil, have been reported to reverse resistance in tumor cells. However, the accompanying side effects have limited their clinical application. In this study, we have developed a novel drug delivery system, ie, a polyethyleneglycol-polycaprolactone (PEG-PCL) copolymer micelle encapsulating doxorubicin, in order to circumvent drug resistance in adriamycin-resistant K562 tumor cells.
  
  
  METHODS
  Doxorubicin-loaded diblock copolymer PEG-PCL micelles were developed, and the physicochemical properties of these micelles, and accumulation and cytotoxicity of doxorubicin in adriamycin-resistant K562 tumor cells were studied.
  
  
  RESULTS
  Doxorubicin-loaded micelles were prepared using a solvent evaporation method with a diameter of 36 nm and a zeta potential of +13.8 mV. The entrapment efficiency of doxorubicin was 48.6% ± 2.3%. The micelles showed sustained release, increased uptake, and cellular cytotoxicity, as well as decreased efflux of doxorubicin in adriamycin-resistant K562 tumor cells.
  
  
  CONCLUSIONS
  This study suggests that PEG-PCL micelles have the potential to reverse multidrug resistance in tumor cells.
authors: Institute of Pharmaceutics, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou.
authors: Yuan-Yuan
authors: YY
authors: Diao
authors: Hao-Ying
authors: HY
authors: Li
authors: Ying-Hua
authors: YH
authors: Fu
authors: Min
authors: M
authors: Han
authors: Yu-Lan
authors: YL
authors: Hu
authors: Hong-Liang
authors: HL
authors: Jiang
authors: Yasuo
authors: Y
authors: Tsutsumi
authors: Qi-Chun
authors: QC
authors: Wei
authors: Da-Wei
authors: DW
authors: Chen
authors: Jian-Qing
authors: JQ
authors: Gao
mesh_terms: D000903:Antibiotics, Antineoplastic / Q000737:chemistry / Q000494:pharmacology*; D002470:Cell Survival / Q000187:drug effects; D004317:Doxorubicin / Q000737:chemistry / Q000494:pharmacology*; D004337:Drug Carriers / Q000737:chemistry* / Q000494:pharmacology; D019008:Drug Resistance, Neoplasm / Q000187:drug effects*; D006801:Humans; D020014:K562 Cells; D008823:Micelles; D011091:Polyesters / Q000737:chemistry; D011092:Polyethylene Glycols / Q000737:chemistry
chemical_list: D000903:Antibiotics, Antineoplastic; D004337:Drug Carriers; D008823:Micelles; D011091:Polyesters; C016240:polycaprolactone; D011092:Polyethylene Glycols; D004317:Doxorubicin