A genetically modified recombinant tumor necrosis factor-alpha conjugated to the distal terminals of liposomal surface grafted polyethyleneglycol chains

Int J Pharm. 1999 Jul 5;184(1):45-51. doi: 10.1016/s0378-5173(99)00092-7.

Abstract

A genetically modified recombinant tumor necrosis factor (TNF)-alpha (rKRKTNF) was conjugated to the terminal carboxyl groups of liposome grafted polyethyleneglycol (PEG) chains. The long-circulating liposomes were composed of egg phosphatidylcholine, cholesterol (chol) and 7% carboxyl PEG-phosphatidylethanolamine. The conjugation efficiency of the genetically modified rKRKTNF under the conditions described in the text was approximately 55%. The biological activity of liposomal rKRKTNF, as tested with an in vitro cytotoxicity assay was reduced compared to the free, unconjugated rKRKTNF. In vivo biodistribution studies showed that conjugation of as little as 0. 13% of the grafted PEG chains resulted in a rapid elimination of the formulation from the blood stream. It is speculated that both non-selective conjugate chemistry and inherent recognition of the TNF by the components of the reticuloendothelial system (RES) are responsible for the short blood half life of the rKRKTNF-PEG-liposomes. The result suggest that conjugating a rapidly clearing recombinant cytokine to long-circulating liposomes provides little advantage in modifying the pharmacokinetic parameters of the cytokine.

Publication types

  • Comparative Study
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Cholesterol / administration & dosage
  • Cholesterol / chemistry
  • Cholesterol / pharmacokinetics
  • Female
  • Liposomes / chemistry
  • Mice
  • Mice, Inbred C3H
  • Pharmaceutic Aids / administration & dosage
  • Pharmaceutic Aids / chemistry*
  • Pharmaceutic Aids / pharmacokinetics
  • Phosphatidylcholines / administration & dosage
  • Phosphatidylcholines / chemistry
  • Phosphatidylcholines / pharmacokinetics
  • Phosphatidylethanolamines / administration & dosage
  • Phosphatidylethanolamines / chemistry
  • Phosphatidylethanolamines / pharmacokinetics
  • Polyethylene Glycols / administration & dosage
  • Polyethylene Glycols / chemistry*
  • Polyethylene Glycols / pharmacokinetics
  • Recombinant Proteins / administration & dosage
  • Recombinant Proteins / chemistry*
  • Recombinant Proteins / genetics
  • Recombinant Proteins / pharmacokinetics
  • Tissue Distribution
  • Tumor Necrosis Factor-alpha / administration & dosage
  • Tumor Necrosis Factor-alpha / chemistry*
  • Tumor Necrosis Factor-alpha / genetics
  • Tumor Necrosis Factor-alpha / pharmacokinetics

Substances

  • Liposomes
  • Pharmaceutic Aids
  • Phosphatidylcholines
  • Phosphatidylethanolamines
  • Recombinant Proteins
  • Tumor Necrosis Factor-alpha
  • Polyethylene Glycols
  • Cholesterol