Synthesis and preliminary evaluation of carbon-11-meta-hydroxyephedrine: a false transmitter agent for heart neuronal imaging

J Nucl Med. 1990 Aug;31(8):1328-34.

Abstract

Carbon-11-meta-hydroxyephedrine is a new radiotracer developed for mapping the sympathetic nerves of the heart. Carbon-11-meta-hydroxyephedrine is synthesized by direct N-methylation of metaraminol with [11C]methyl iodide in dimethyl formamide/dimethyl sulfoxide and purified by semi-preparative reversed-phase HPLC. Total synthesis time is 45 min from end-of-bombardment. Carbon-11-meta-hydroxyephedrine is produced in 40%-50% corrected radiochemical yield with a specific activity of 900 Ci/mmol. Routine radiochemical and chemical purity are 95% and 98%, respectively. Biodistribution studies in rats show high myocardial uptake. Pretreatment with desipramine, a drug known to selectively block neuronal uptake, results in a 92% decrease in tracer accumulation in the myocardium. Metabolic studies in guinea pigs show less than 5% metabolites in heart tissue 30 min after intravenous injection suggesting that [11C]meta-hydroxyephedrine is suitable for kinetic modeling. These preliminary results support this new tracer as a clinical agent for neuronal imaging of the heart.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Chemical Phenomena
  • Chemistry
  • Desipramine / pharmacology
  • Ephedrine / analogs & derivatives*
  • Ephedrine / chemical synthesis
  • Evaluation Studies as Topic
  • Female
  • Guinea Pigs
  • Heart / diagnostic imaging
  • Heart / innervation*
  • Male
  • Myocardium / metabolism*
  • Radioactive Tracers
  • Rats
  • Rats, Inbred Strains
  • Sympathetic Nervous System / diagnostic imaging*
  • Sympathetic Nervous System / drug effects
  • Sympathetic Nervous System / metabolism
  • Tissue Distribution
  • Tomography, Emission-Computed*

Substances

  • Radioactive Tracers
  • 3-hydroxyephedrine
  • Ephedrine
  • Desipramine