Stealth Me.PEG-PLA nanoparticles avoid uptake by the mononuclear phagocytes system

J Pharm Sci. 1995 Apr;84(4):493-8. doi: 10.1002/jps.2600840420.


Nanoparticles were prepared from methoxy poly(ethylene glycol)poly(d,l-lactic acid) block copolymers (Me.PEG-PLA) or blends of Me.PEG-PLA and PLA by the precipitation-solvent diffusion method. These nanoparticles, labeled by introducing [14C]PLA in the formulation, were shown to be more slowly captured by cultured THP-1 monocytes than F68-coated PLA nanoparticles, in a PEG chain-length-dependent manner. In vivo, the half-life in plasma of the Me.PEG-PLA nanoparticles that were intravenously administered to rats is increased by a factor 180 compared with the F68-coated PLA nanoparticles. This mononuclear phagocytes system avoidance was explained according to a conformation model in which the PEG density at the surface of the particles is a key parameter.

MeSH terms

  • Animals
  • Autoradiography
  • Colorimetry
  • Drug Carriers
  • In Vitro Techniques
  • Lactates / chemical synthesis*
  • Lactates / isolation & purification
  • Lactic Acid*
  • Leukocytes, Mononuclear / metabolism*
  • Male
  • Microspheres
  • Particle Size
  • Phagocytosis
  • Polyesters
  • Polyethylene Glycols / analysis
  • Polyethylene Glycols / chemical synthesis*
  • Polyethylene Glycols / isolation & purification
  • Polymers / chemical synthesis*
  • Polymers / isolation & purification
  • Rats
  • Rats, Sprague-Dawley
  • Surface Properties
  • Tissue Distribution


  • Drug Carriers
  • Lactates
  • Polyesters
  • Polymers
  • Lactic Acid
  • Polyethylene Glycols
  • poly(lactide)
  • monomethoxypolyethylene glycol