title: Toward [18F]-labeled aryltrifluoroborate radiotracers: in vivo positron emission tomography imaging of stable aryltrifluoroborate clearance in mice.
abstract: The use of a boronic ester as a captor of aqueous [(18)F]-fluoride has been previously suggested as a means of labeling biomolecules in one step for positron emission tomography (PET) imaging. For this approach to be seriously considered, the [(18)F]-labeled trifluoroborate should be humorally stable such that it neither leaches free [(18)F]-fluoride to the bone nor accumulates therein. Herein, we have synthesized a biotinylated boronic ester that is converted to the corresponding trifluoroborate salt in the presence of aqueous [(18)F]-fluoride. In keeping with its in vitro aqueous kinetic stability at pH 7.5, the trifluoroborate appears to clear in vivo quite rapidly to the bladder as the stable trifluoroborate salt with no detectable leaching of free [(18)F]-fluoride to the bone. When this labeled biotin is preincubated with avidin, the pharmacokinetic clearance of the resulting complex is visibly altered. This work validates initial claims that boronic esters are potentially useful as readily labeled precursors to [(18)F]-PET reagents.
authors.affiliation: Chemistry Department, University of British Columbia, 2036 Main Mall, Vancouver, B.C. V6T-1Z1, Canada.
authors.forename: Richard
authors.initials: R
authors.lastname: Ting
authors.forename: Curtis
authors.initials: C
authors.lastname: Harwig
authors.forename: Ulrich
authors.initials: U
authors.lastname: auf dem Keller
authors.forename: Siobhan
authors.initials: S
authors.lastname: McCormick
authors.forename: Pamela
authors.initials: P
authors.lastname: Austin
authors.forename: Christopher M
authors.initials: CM
authors.lastname: Overall
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Adam
authors.forename: Thomas J
authors.initials: TJ
authors.lastname: Ruth
authors.forename: David M
authors.initials: DM
authors.lastname: Perrin
mesh_terms: D000818:Animals; D001881:Borates / Q000138:chemical synthesis / Q000737:chemistry* / Q000493:pharmacokinetics*; D005260:Female; D005462:Fluorine Radioisotopes / Q000737:chemistry; D007553:Isotope Labeling / Q000379:methods; D007700:Kinetics; D051379:Mice; D008807:Mice, Inbred BALB C; D049268:Positron-Emission Tomography / Q000379:methods; D019275:Radiopharmaceuticals / Q000138:chemical synthesis / Q000737:chemistry* / Q000493:pharmacokinetics*; D013816:Thermodynamics
chemical_list: D001881:Borates; D005462:Fluorine Radioisotopes; D019275:Radiopharmaceuticals; C098759:fluoroboric acid