title: Effects of a novel pH-sensitive liposome with cleavable esterase-catalyzed and pH-responsive double smart mPEG lipid derivative on ABC phenomenon.
abstract: BACKGROUND
  The ABC phenomenon is described as a syndrome of accelerated clearance of polyethylene glycol (PEG)-modified liposomes from the bloodstream when repeatedly injected, with their increased accumulation in the liver and spleen.
  
  
  METHODS
  To clarify this immune response phenomenon, we evaluated a novel modified pH-sensitive liposome with a cleavable double smart PEG-lipid derivative (mPEG-Hz-CHEMS).
  
  
  RESULTS
  The ABC phenomenon in mice was brought about by repeated injection of conventional PEG-PE liposomes and was accompanied by a greatly increased uptake in the liver. However, a slight ABC phenomenon was brought about by repeated injection of mPEG-CHEMS liposomes and was accompanied by only a slightly increased uptake in the liver, and repeated injection of mPEG-Hz-CHEMS liposomes did not induce the ABC phenomenon and there was no increase in liver accumulation. This finding indicates that the cleavable mPEG-Hz-CHEMS derivative could lessen or eliminate the ABC phenomenon induced by repeated injection of PEGylated liposomes.
  
  
  CONCLUSIONS
  This research has shed some light on a solution to the ABC phenomenon using a cleavable PEG-Hz-CHEMS derivative encapsulated in nanoparticles.
authors: School of Pharmacy, Yantai University, Yantai.
authors: Daquan
authors: D
authors: Chen
authors: Wanhui
authors: W
authors: Liu
authors: Yan
authors: Y
authors: Shen
authors: Hongjie
authors: H
authors: Mu
authors: Yanchun
authors: Y
authors: Zhang
authors: Rongcai
authors: R
authors: Liang
authors: Aiping
authors: A
authors: Wang
authors: Kaoxiang
authors: K
authors: Sun
authors: Fenghua
authors: F
authors: Fu
mesh_terms: D000818:Animals; D005260:Female; D007275:Injections, Intravenous; D008081:Liposomes / Q000008:administration & dosage / Q000737:chemistry / Q000493:pharmacokinetics; D008099:Liver / Q000378:metabolism; D008657:Metabolic Clearance Rate / Q000502:physiology; D051379:Mice; D010714:Phosphatidylethanolamines / Q000737:chemistry*; D011092:Polyethylene Glycols / Q000008:administration & dosage / Q000737:chemistry / Q000493:pharmacokinetics; D013154:Spleen / Q000378:metabolism; D014018:Tissue Distribution
chemical_list: D008081:Liposomes; D010714:Phosphatidylethanolamines; C038089:1,2-distearoylphosphatidylethanolamine; D011092:Polyethylene Glycols; C028210:monomethoxypolyethylene glycol