The radiosynthesis of [18F]PK 14105 as an alternative radioligand for peripheral type benzodiazepine binding sites

C. Pascali, S. K. Luthra, V. W. Pike, G. W. Price, R. G. Ahier, S. P. Hume, R. Myers, L. Manjil, J. E. Cremer

Research output: Contribution to journalArticlepeer-review

Abstract

A method has been developed for labelling PK 14105 [N-methyl-N-(1-methyl-propyl)-1(2-fluoro-5-nitro- phenyl)isoquinoline-3-carboxamide], a ligand that has high affinity and selectivity for peripheral type benzodiazepine binding sites (PBBS), with NCA fluorine-18 (t 1 2 = 109.8 min, β+ = 96.9%). The method involves treating the 2-chloro-analogue with cyclotron-produced NCA [18F]fluoride in dimethyl sulphoxide, with rubidium carbonate as base, at 140°C for 20 min. Purification is achieved by separation on a reverse phase Sep-Pak followed by HPLC on a silica gel column, to give chemically and radiochemically pure product with a specific activity of ca 7.4 GBq/μmol (200 mCi/μmol), decay-corrected to the end of radionuclide production (EOB). The radiosynthesis requires 210 min, giving a radiochemical yield of 10-20%, decay-corrected to EOB. [18F]PK 14105 was found to bind avidly to sites associated with kainic acid-induced unilateral lesions of rat striata. Such binding was blocked by pre-dosing the rat with PK 11195, so providing evidence for specific binding to PBBS. These results suggest that [18F]PK 14105 has potential for studying phenomena associated with PBBS in man by PET.

Original languageEnglish
Pages (from-to)477-482
Number of pages6
JournalInternational Journal of Radiation Applications and Instrumentation. Part
Volume41
Issue number5
DOIs
Publication statusPublished - 1990

ASJC Scopus subject areas

  • Engineering(all)
  • Radiation
  • Medicine(all)

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