title: The influence of polysorbate 80 on the radiochemical synthesis of a PET tracer in the FASTlab.
abstract: OBJECTIVE
  The aim of current study was to investigate the influence of a common non-ionic surfactant, polysorbate 80 (PS80), on radioactive labelling process of a novel PET tracer, [(18)F]Flutemetamol.
  
  
  METHODS
  Ferrous oxidation-xylenol orange (FOX) assay, in addition to UV/VIS and (1)H NMR spectroscopies were applied to characterise the composition of the PS80 solution after storage. Multivariate Curve Resolution (MCR) and PLS analysis was used to establish correlation between quality of the PS80 solution and the RCP obtained after labelling.
  
  
  RESULTS
  The levels of unsaturated fatty acid moieties of PS80 were negatively correlated to RCP of [(18)F]Flutemetamol after synthesis. This explains the slight increase in RCP when stored PS80 solutions were applied in the synthesis. The mechanism behind this observation is suggested to be related to radiation induced radical formation in the unsaturated fatty acids, which subsequently causes instability of the PET tracer. UV/VIS spectroscopy was demonstrated to have the ability as a possible control tool for quality assurance of the studied radioactive labelling process.
  
  
  CONCLUSIONS
  The presence of unsaturated fatty acid moieties in PS80 was found to be one of the most important factors responsible for the reduction in RCP of [(18)F]Flutemetamol after synthesis.
authors.affiliation: School of Pharmacy, Department of Pharmacy, University of Oslo, P.O. Box 1068 Blindern, 0316, Oslo, Norway, waiy@farmasi.uio.no.
authors.forename: Wai Lam
authors.initials: WL
authors.lastname: Yip
authors.forename: Sverre Arne
authors.initials: SA
authors.lastname: Sande
authors.forename: David
authors.initials: D
authors.lastname: Grace
authors.forename: Dirk Jan
authors.initials: DJ
authors.lastname: in't Veld
authors.forename: Per Christian
authors.initials: PC
authors.lastname: Sontum
authors.forename: Tina
authors.initials: T
authors.lastname: Solvang
authors.forename: Knut
authors.initials: K
authors.lastname: Dyrstad
mesh_terms: D000814:Aniline Compounds / Q000138:chemical synthesis* / Q000737:chemistry*; D052160:Benzothiazoles / Q000138:chemical synthesis* / Q000737:chemistry*; D002851:Chromatography, High Pressure Liquid; D004355:Drug Stability; D005462:Fluorine Radioisotopes; D007553:Isotope Labeling; D011136:Polysorbates / Q000737:chemistry*; D049268:Positron-Emission Tomography; D011849:Radioactive Tracers; D012995:Solubility; D013501:Surface-Active Agents / Q000737:chemistry*
chemical_list: D000814:Aniline Compounds; D052160:Benzothiazoles; D005462:Fluorine Radioisotopes; D011136:Polysorbates; D011849:Radioactive Tracers; D013501:Surface-Active Agents; C581552:flutemetamol