Preparation and characterization of microspheres of albumin-heparin conjugates

Glen S. Kwon, You Han Bae, Sung Wan Kim, Harry Cremers, H.F.M. Cremers, Jan Feijen

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Albumin-heparin microspheres have been prepared as a new drug carrier. A soluble albumin-heparin conjugate was synthesized by forming amide bonds between human serum albumin and heparin. After purification the albumin-heparin conjugate was crosslinked in a water-in-oil emulsion to form albumin-heparin microspheres. The composition of the conjugate was determined by amino acid analysis. The swelling properties of albumin-heparin microspheres were investigated as a function of pH and ionic strength and compared with albumin microspheres. Albumin-heparin and albumin microspheres exhibited stimuli-sensitive swelling. Both microsphere systems exhibited low swelling at low pH and high swelling at higher pH caused by ionization of amino acids of serum albumin. The swelling of albumin-heparin microspheres was more sensitive toward ionic strength than that of albumin microspheres. This was due to the greater negative charge of the albumin-heparin microspheres. Surfaces of albumin-heparin and albumin microspheres were characterized by ESCA, contact angle measurements, electrophoresis, and scanning electron microscopy. Surface analysis indicated the presence of heparin at the albumin-heparin microsphere/water interface.
Original languageUndefined
Pages (from-to)501-512
Number of pages12
JournalJournal of colloid and interface science
Issue number2
Publication statusPublished - 1991


  • METIS-105238
  • IR-73004

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