Positron-labeled angiotensin-converting enzyme (ACE) inhibitor: Fluorine-18-fluorocaptopril. Probing the ACE activity in vivo by positron emission tomography

Journal Article · Sun Sep 01 04:00:00 EDT 1991 · Journal of Nuclear Medicine; (United States)

OSTI ID:5013293

Hwang, D R; Eckelman, W C; Mathias, C J; Petrillo, Jr, E W; Lloyd, J; Welch, M J ^[1]

---

1. Edward Mallinckrodt Institute of Radiology, Washington University School of Medicine, St. Louis, MO (United States)

To evaluate the feasibility of probing the distribution of angiotensin-converting enzyme (ACE) in vivo using positron emission tomography (PET), 4-cis-(18F)fluorocaptopril (18FCAP) was prepared by the reaction of the triflate 2 with K18F/Kryptofix 222 in MeCN followed by hydrolysis (2 N NaOH). The synthesis time was 1 hr with an average radiochemical yield (EOS) of 12% and a specific activity of greater than 300 Ci/mmol. In vivo biodistribution in rats at 30 min after administration showed high uptakes into organs known to have high ACE concentration (lung, kidney and aorta) and faster clearance of 18FCAP for lung and kidney, compared to the clearance from the aorta. When different amounts of unlabeled 4-cis-fluorocaptopril (SQ 25750) were coinjected in rats, a dose of greater than 5 micrograms/kg decreased the lung uptake by one-half while only 1 microgram/kg decreased the kidney uptake by one-half. In general, the binding in the four tissues studied was saturable with the expected capacity. 18FCAP was administered to a human and displaceable uptake observed in the lung and kidney. The results demonstrate the feasibility of probing ACE in vivo using PET.

• OSTI ID: 5013293
• Journal Information: Journal of Nuclear Medicine; (United States), Journal Name: Journal of Nuclear Medicine; (United States) Vol. 32:9; ISSN 0161-5505; ISSN JNMEA
• Country of Publication: United States
• Language: English

Related Subjects

550601* -- Medicine-- Unsealed Radionuclides in Diagnostics
62 RADIOLOGY AND NUCLEAR MEDICINE
ANIMALS
CHEMICAL PREPARATION
COMPUTERIZED TOMOGRAPHY
DIAGNOSTIC TECHNIQUES
DISTRIBUTION
DRUGS
EMISSION COMPUTED TOMOGRAPHY
ENZYME ACTIVITY
ENZYME INHIBITORS
ENZYMES
FEASIBILITY STUDIES
HYDROLASES
LABELLED COMPOUNDS
MAMMALS
MAN
METABOLISM
PEPTIDE HYDROLASES
POSITRON COMPUTED TOMOGRAPHY
PRIMATES
RADIOPHARMACEUTICALS
RATS
RODENTS
SYNTHESIS
TISSUE DISTRIBUTION
TOMOGRAPHY
VERTEBRATES