title: Evasion of the accelerated blood clearance phenomenon by coating of nanoparticles with various hydrophilic polymers.
abstract: The accelerated blood clearance (ABC) phenomenon is induced upon repeated injections of poly(ethylene glycol) (PEG)-coated colloidal carriers. It is essential to suppress this phenomenon in a clinical setting because the pharmacokinetics must be reproducible. In this study, we evaluated the induction of the ABC phenomenon using nanoparticles coated with various hydrophilic polymers instead of PEG. Nanoparticles encapsulating prostaglandin E1 were prepared by the solvent diffusion method from a blend of poly(lactic acid) (PLA) and block copolymers consisting of various hydrophilic polymers and PLA. Coating of nanoparticles with poly(N-vinyl-2-pyrrolidone) (PVP), poly(4-acryloylmorpholine), or poly(N,N-dimethylacrylamide) led to extended residence of the nanoparticles in blood circulation in rats, although they had a shorter half-life than the PEG-coated nanoparticles. The ABC phenomenon was not induced upon repeated injection of PVP-coated nanoparticles at various time intervals, dosages, or frequencies, whereas it was elicited by PEG-coated nanoparticles. In addition, anti-PVP IgM antibody, which is estimated to be one of the crucial factors for induction of the ABC phenomenon, was not produced after injection of PVP-coated nanoparticles. These results suggest that the use of PVP, instead of PEG, as a coating material for colloidal carriers can evade the ABC phenomenon.
authors.affiliation: Graduate School of Medical and Pharmaceutical Sciences, Kumamoto University, Kumamoto, Japan. ishihara@chem.ce.nihon-u.ac.jp
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Ishihara
authors.forename: Taishi
authors.initials: T
authors.lastname: Maeda
authors.forename: Haruka
authors.initials: H
authors.lastname: Sakamoto
authors.forename: Naoko
authors.initials: N
authors.lastname: Takasaki
authors.forename: Masao
authors.initials: M
authors.lastname: Shigyo
authors.forename: Tatsuhiro
authors.initials: T
authors.lastname: Ishida
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Kiwada
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Mizushima
authors.forename: Tohru
authors.initials: T
authors.lastname: Mizushima
mesh_terms: D000818:Animals; D001776:Blood Circulation Time; D004337:Drug Carriers / Q000008:administration & dosage / Q000009:adverse effects / Q000493:pharmacokinetics*; D004797:Enzyme-Linked Immunosorbent Assay; D057927:Hydrophobic and Hydrophilic Interactions; D007075:Immunoglobulin M / Q000097:blood; D007275:Injections, Intravenous; D008297:Male; D008657:Metabolic Clearance Rate; D053758:Nanoparticles / Q000008:administration & dosage / Q000009:adverse effects / Q000737:chemistry*; D011108:Polymers / Q000008:administration & dosage / Q000009:adverse effects / Q000493:pharmacokinetics*; D011145:Polyvinyls / Q000008:administration & dosage / Q000009:adverse effects; D011759:Pyrrolidines / Q000008:administration & dosage / Q000009:adverse effects / Q000097:blood; D051381:Rats; D017208:Rats, Wistar
chemical_list: D004337:Drug Carriers; D007075:Immunoglobulin M; D011108:Polymers; D011145:Polyvinyls; D011759:Pyrrolidines; C505150:poly(N-vinylpyrrolidine)