Synthesis and evaluation of p-iodophentermine (IP) as a brain perfusion imaging agent
Recently N-isopropyl-rho-(/sup 123/I)-iodoamphetamine (IMP) has been reported as a potential cerebral perfusion imaging agent for single-photon emission tomography (SPECT). Since addition of a methyl group in the alpha position of amphetamine results in increased lipophilicity and prolonged residence time of the compound in the brain, the authors synthesized and evaluated the biological behaviour of rho-Iodo phenteramine (IP). IP was prepared by diazotization of rho-aminophentermine followed by decomposition of the diazonium salt with KI. Radioiodinated analog was prepared either by the solid-phase isotopic exchange reaction of Mangner et al or by decomposition of the piperidinotrazine derivative with a radiochemical yield of 40-60%. Biodistribution in rats showed that the brain concentration of /sup 131/I-IP was 1.69 +- 0.53, 1.70 +- 0.23 and 1.72 +- 0.11% injected dose/g tissue at 5, 30 and 60 min respectively, after IV injection. The lung uptake was 10.82% ID/g at 5 min and decreased to 7.7% ID/g at 60 min. The thyroid activity was low during the first hour of the study indicating minimal deiodination on the aryl ring. Sequential images of the brains of three dogs after intracarotid injection of /sup 123/I-IP showed localization of activity to one hemisphere of the brain, and clearance of <15% at one hour. In addition, SPECT images revealed more intense localization in the region of gray matter then white matter in the brain.
- Research Organization:
- Massachusetts General Hospital, Boston, MA 02114
- OSTI ID:
- 6477894
- Report Number(s):
- CONF-840619-; TRN: 87-022121
- Journal Information:
- J. Nucl. Med.; (United States), Vol. 25:5; Conference: 31. annual meeting of the Society of Nuclear Medicine, Los Angeles, CA, USA, 5 Jun 1984
- Country of Publication:
- United States
- Language:
- English
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62 RADIOLOGY AND NUCLEAR MEDICINE
AMPHETAMINES
CHEMICAL PREPARATION
EVALUATION
STRUCTURE-ACTIVITY RELATIONSHIPS
TISSUE DISTRIBUTION
UPTAKE
BRAIN
RADIONUCLIDE KINETICS
SINGLE PHOTON EMISSION COMPUTED TOMOGRAPHY
CHEMICAL REACTIONS
DOGS
IODINE 131
LUNGS
RADIOPHARMACEUTICALS
RATS
ANALEPTICS
ANIMALS
AUTONOMIC NERVOUS SYSTEM AGENTS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BODY
CENTRAL NERVOUS SYSTEM
CENTRAL NERVOUS SYSTEM AGENTS
COMPUTERIZED TOMOGRAPHY
DAYS LIVING RADIOISOTOPES
DIAGNOSTIC TECHNIQUES
DISTRIBUTION
DRUGS
EMISSION COMPUTED TOMOGRAPHY
INTERMEDIATE MASS NUCLEI
IODINE ISOTOPES
ISOTOPES
LABELLED COMPOUNDS
MAMMALS
NERVOUS SYSTEM
NUCLEI
ODD-EVEN NUCLEI
ORGANS
RADIOISOTOPES
RESPIRATORY SYSTEM
RODENTS
SYMPATHOMIMETICS
SYNTHESIS
TOMOGRAPHY
VERTEBRATES
550501* - Metabolism- Tracer Techniques
550601 - Medicine- Unsealed Radionuclides in Diagnostics
550201 - Biochemistry- Tracer Techniques