Synthesis and in vitro and in vivo evaluation of 18F-labeled positron emission tomography (PET) ligands for imaging the vesicular acetylcholine transporter

J Med Chem. 2009 Mar 12;52(5):1358-69. doi: 10.1021/jm8012344.

Abstract

A new class of vesicular acetylcholine transporter inhibitor that incorporates a carbonyl group into the benzovesamicol structure was synthesized, and analogues were evaluated in vitro. (+/-)-trans-2-Hydroxy-3-(4-(4-[(18)F]fluorobenzoyl)piperidino)tetralin (9e) has K(i) values of 2.70 nM for VAChT, 191 nM for sigma(1), and 251 nM for sigma(2). The racemic precursor (9d) was resolved via chiral HPLC, and (+/-)-[(18)F]9e, (-)-[(18)F]9e, and (+)-[(18)F]9e were respectively radiolabeled via microwave irradiation of the appropriate precursors with [(18)F]/F(-) and Kryptofix/K(2)CO(3) in DMSO with radiochemical yields of approximately 50-60% and specific activities of >2000 mCi/micromol. (-)-[(18)F]9e uptake in rat brain was consistent with in vivo selectivity for the VAChT with an initial uptake of 0.911 %ID/g in rat striatum and a striatum/cerebellum ratio of 1.88 at 30 min postinjection (p.i.). MicroPET imaging of macaques demonstrated a 2.1 ratio of (-)-[(18)F]9e in putamen versus cerebellum at 2 h p.i. (-)-[(18)F]9e has potential to be a PET tracer for clinical imaging of the VAChT.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Animals
  • Autoradiography
  • Brain / diagnostic imaging
  • Brain / metabolism
  • Chromatography, High Pressure Liquid
  • Crystallography, X-Ray
  • Fluorine Radioisotopes
  • Guinea Pigs
  • In Vitro Techniques
  • Ligands
  • Macaca mulatta
  • Male
  • Piperidines / chemical synthesis*
  • Piperidines / chemistry
  • Piperidines / pharmacokinetics
  • Positron-Emission Tomography
  • Protein Binding
  • Radiopharmaceuticals / chemical synthesis*
  • Radiopharmaceuticals / chemistry
  • Radiopharmaceuticals / pharmacokinetics
  • Rats
  • Rats, Sprague-Dawley
  • Stereoisomerism
  • Structure-Activity Relationship
  • Tetrahydronaphthalenes / chemical synthesis*
  • Tetrahydronaphthalenes / chemistry
  • Tetrahydronaphthalenes / pharmacokinetics
  • Tissue Distribution
  • Torpedo
  • Vesicular Acetylcholine Transport Proteins / metabolism*

Substances

  • 2-hydroxy-3-(4-(4-fluorobenzoyl)piperidino)tetralin
  • Fluorine Radioisotopes
  • Ligands
  • Piperidines
  • Radiopharmaceuticals
  • Tetrahydronaphthalenes
  • Vesicular Acetylcholine Transport Proteins