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Physical and biochemical characterization of Albunex, a new ultrasound contrast agent consisting of air‐filled albumin microspheres suspended in a solution of human albumin
Author(s) -
Christiansen C.,
Kryvi H.,
Sontum P.,
Skotland T.
Publication year - 1994
Publication title -
biotechnology and applied biochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.468
H-Index - 70
eISSN - 1470-8744
pISSN - 0885-4513
DOI - 10.1111/j.1470-8744.1994.tb00300.x
Subject(s) - albumin , sonication , microbubbles , suspension (topology) , chromatography , chemistry , human albumin , particle size , microsphere , ultrasound , materials science , chemical engineering , biochemistry , medicine , mathematics , homotopy , pure mathematics , radiology , engineering
Albunex is a new ultrasound contrast agent for medical imaging. The product consists of air‐filled albumin microspheres suspended in a solution of 5% (w/v) human albumin. The suspension is sterile, non‐pyrogenic and isotonic, with a pH of 7.0 and a viscosity of 1.4 relative to water. The contrast effect is caused by the air‐filled microspheres, which range in diameter from 1 to 15 microns, with less than 5% being larger than 10 microns. The product contains a total of about 7 times 10(8) microspheres/ml of suspension. The number concentration of microspheres with diameters between 4 and 10 microns is about 2 times 10(8)/ml. The latter microsphere fraction is assumed to give the main contribution to the ultrasound signal in the left ventricle of the heart after intravenous injection. The air‐filled microspheres are prepared by sonication of a heated solution of 5% (w/v) human albumin. During the sonication process, microbubbles of air are formed which become encapsulated in a thin shell of aggregated albumin about 15 nm in thickness. Due to the stabilizing effect of the albumin shell, the air‐filled microsphere suspension is stable for at least 2 years when stored refrigerated. The microsphere protein represents about 1.5% of the total protein in the suspension. The remaining protein is soluble albumin molecules which behave like the albumin molecules in the starting material when analysed by a number of biochemical techniques.