title: Long-circulating non-toxic blood pool imaging agent based on hyperbranched polyglycerols.
abstract: OBJECTIVE
  Currently, in vivo or in vitro(99m)Tc-radiolabelled red blood cells are the standard blood pool imaging agents. Due to risks associated with handling of blood and the problems with the current (99m)Tc shortage, we were interested in a long-circulating biocompatible synthetic macromolecule that would be simple to prepare and could also be used for PET imaging.
  
  
  METHODS
  A high molecular weight hyperbranched polyglycerol (HPG) of 500 kDa was derivatized to coordinate radioactive gallium and to establish its labelling efficiency, stability and pharmacokinetics.
  
  
  RESULTS
  The resulting radiopharmaceutical in kit form was labelled rapidly within a couple of minutes at room temperature, was stable in transferrin and EDTA challenge tests, and was non-toxic in both cell viability and different hemocompatibility assays. A pharmacokinetic biodistribution study showed that the (67)Ga-HPGN was confined to the blood compartment with a biological half life of 50.7h.
  
  
  CONCLUSIONS
  (67)Ga-HPGN is thus a simple to prepare blood pool imaging agent for applications where a long biological half-life is essential, i.e., the diagnosis of internal bleeding. Since radiolabelling of the same kit with (68)Ga was also confirmed, we plan to evaluate it shortly as a PET blood pool imaging agent for cardiac applications.
authors: Faculty of Pharmaceutical Sciences, University of British Columbia, Vancouver, British Columbia, Canada.
authors: Katayoun
authors: K
authors: Saatchi
authors: Nikolaus
authors: N
authors: Gelder
authors: Pavel
authors: P
authors: Gershkovich
authors: Olena
authors: O
authors: Sivak
authors: Kishor M
authors: KM
authors: Wasan
authors: Rajesh K
authors: RK
authors: Kainthan
authors: Donald E
authors: DE
authors: Brooks
authors: Urs O
authors: UO
authors: Häfeli
mesh_terms: D000818:Animals; D001777:Blood Coagulation / Q000187:drug effects; D002470:Cell Survival; D002478:Cells, Cultured; D003167:Complement Activation; D004903:Erythrocyte Aggregation / Q000187:drug effects; D005710:Gallium Radioisotopes / Q000008:administration & dosage / Q000097:blood / Q000737:chemistry / Q000493:pharmacokinetics* / Q000633:toxicity; D015637:Gated Blood-Pool Imaging / Q000379:methods*; D005990:Glycerol / Q000008:administration & dosage / Q000097:blood / Q000737:chemistry / Q000493:pharmacokinetics* / Q000633:toxicity; D006207:Half-Life; D061307:Human Umbilical Vein Endothelial Cells / Q000187:drug effects / Q000473:pathology; D006801:Humans; D007275:Injections, Intravenous; D015394:Molecular Structure; D008970:Molecular Weight; D010314:Partial Thromboplastin Time; D015539:Platelet Activation / Q000187:drug effects; D011108:Polymers / Q000008:administration & dosage / Q000737:chemistry / Q000493:pharmacokinetics* / Q000633:toxicity; D049268:Positron-Emission Tomography; D011517:Prothrombin Time; D019275:Radiopharmaceuticals / Q000008:administration & dosage / Q000097:blood / Q000737:chemistry / Q000493:pharmacokinetics* / Q000633:toxicity; D051381:Rats; D017207:Rats, Sprague-Dawley; D013916:Thrombelastography; D014018:Tissue Distribution
chemical_list: D005710:Gallium Radioisotopes; D011108:Polymers; D019275:Radiopharmaceuticals; C043941:polyglycerol; D005990:Glycerol