Automated synthesis and preliminary evaluation of [18F]FDPA for cardiac inflammation imaging in rats after myocardial infarction

Sci Rep. 2020 Oct 29;10(1):18685. doi: 10.1038/s41598-020-75705-2.

Abstract

A translocator protein 18 kDa targeted radiotracer, N,N-diethyl-2-(2-(4-[18F]fluorophenyl)-5,7-dimethylpyrazolo[1,5-a] pyrimidin-3-yl) acetamide ([18F]FDPA), was automated synthetized and evaluated for cardiac inflammation imaging. Various reaction conditions for an automated synthesis were systematically optimized. MicroPET/CT imaging were performed on normal rats and rats with myocardial infarction (MI). Normalized SUV ratios of [18F]FDPA to [13N]NH3 (NSRs) in different regions were calculated to normalize the uptake of [18F]FDPA to perfusion. The amount of TBAOMs and the volume/proportion of water were crucial for synthesis. After optimization, the total synthesis time was 68 min. The non-decay corrected radiochemical yields (RCYs) and molar activities were 19.9 ± 1.7% and 169.7 ± 46.5 GBq/μmol, respectively. In normal rats, [18F]FDPA showed a high and stable cardiac uptake and fast clearance from other organs. In MI rats, NSRs in the peri-infarct and infarct regions, which were infiltrated with massive inflammatory cells revealed by pathology, were higher than that in the remote region (1.20 ± 0.01 and 1.08 ± 0.10 vs. 0.89 ± 0.05, respectively). [18F]FDPA was automated synthesized with high RCYs and molar activities. It showed a high uptake in inflammation regions and offered a wide time window for cardiac imaging, indicating it could be a potential cardiac inflammation imaging agent.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Automation
  • Fluorine Radioisotopes / administration & dosage*
  • Male
  • Myocardial Infarction / complications*
  • Myocarditis / diagnostic imaging*
  • Myocarditis / etiology
  • Positron Emission Tomography Computed Tomography
  • Radiopharmaceuticals / administration & dosage*
  • Rats
  • Rats, Sprague-Dawley

Substances

  • Fluorine Radioisotopes
  • Radiopharmaceuticals