title: Molecular-size fractionation of pentastarch, radiolabelling with 99mTc, and evaluation of biological behaviour in mice.
abstract: BACKGROUND
  Pentastarch is used clinically as a plasma volume expander for the management of substantial blood loss. 99mTc labelled pentastarch may be useful as a diagnostic agent in place of 99mTc labelled red blood cells.
  
  
  METHODS
  Commercial pentastarch (PS; molecular weight (MW) 240 kDa) was separated according to molecular size by using chromatography, and the fractions were pooled as small (MW 128 kDa), medium (MW 277 kDa) and large (MW 510 kDa) pentastarch. We studied the effect of various physicochemical parameters on the efficiency of radiolabelling with 99mTc and on the stability of the products, and evaluated the biological properties of the 99mTc labelled preparations.
  
  
  RESULTS
  We developed an optimised kit formulation containing 3.25 mg pentastarch and 0.13 mg gentisic acid that can be reliably labelled with 99mTc at pH 6.6-8.2 with good stability. In mice, the 99mTc labelled medium pentastarch showed the more favourable blood retention properties (56% of initial blood activity is retained after 3 h) with lower liver levels.
authors.affiliation: Department of Radiopharmacy, Health Sciences Centre, Winnipeg, Manitoba, Canada. Kmangera@hsc.mb.ca
authors.forename: Kennedy
authors.initials: K
authors.lastname: Mang'era
authors.forename: Margaret
authors.initials: M
authors.lastname: Krzyzelewski
authors.forename: Shelley
authors.initials: S
authors.lastname: Greaves
authors.forename: David
authors.initials: D
authors.lastname: Greenberg
authors.forename: Mervyn
authors.initials: M
authors.lastname: Billinghurst
mesh_terms: D000818:Animals; D005591:Chemical Fractionation; D006863:Hydrogen-Ion Concentration; D006895:Hydroxyethyl Starch Derivatives / Q000097:blood / Q000737:chemistry* / Q000493:pharmacokinetics*; D007553:Isotope Labeling / Q000379:methods*; D008297:Male; D008657:Metabolic Clearance Rate; D051379:Mice; D008970:Molecular Weight; D009928:Organ Specificity; D010316:Particle Size; D019275:Radiopharmaceuticals / Q000097:blood / Q000737:chemistry / Q000493:pharmacokinetics; D013667:Technetium / Q000097:blood / Q000737:chemistry* / Q000493:pharmacokinetics*; D014018:Tissue Distribution
chemical_list: D006895:Hydroxyethyl Starch Derivatives; D019275:Radiopharmaceuticals; D013667:Technetium