Preparation and pharmacological evaluation of a new central muscarinic cholinergic receptor imaging agent [76Br]-4-bromodexetimide

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dc.contributor.authorKassiou, Men_AU
dc.contributor.authorLoc'h, Cen_AU
dc.contributor.authorBottlander, MAen_AU
dc.contributor.authorLambrecht, RMen_AU
dc.contributor.authorKatsifis, Aen_AU
dc.contributor.authorSchmid, Len_AU
dc.contributor.authorOttavivani, Men_AU
dc.contributor.authorMazière, Men_AU
dc.contributor.authorMazière , Ben_AU
dc.date.accessioned2025-10-30T00:44:51Zen_AU
dc.date.available2025-10-30T00:44:51Zen_AU
dc.date.issued1983-10-25en_AU
dc.date.statistics2025-08-08en_AU
dc.descriptionPhysical copy held by ANSTO Library at DDC: 616.07575/115.en_AU
dc.description.abstractMuscarinic cholinergic receptors (mAChR) play an important role in a number of physiological and behavioural responses. The putative role of muscarinic receptors in neurodegenerative disorders such as Alzheimer's disease, Huntington's disease and dementias associated with Parkinson's disease has generated considerable interest for the non invasive mapping of mAChR. Potential muscarinic imaging agents include 11C- and 123I-QNB analogs, 11C-scopolamine and 11C-benztropine while radiolabelled dexetimide derivatives have shown exciting potential. Simpler methods for the preparation of dexetirnide derivatives incorporating. longer lived isotopes suitable forPET studies is required. We are reporting the synthesis and the pharmacological characterisation of a bromine-76 derivative of dexetimide suitable for PET studies. The radiosynthesis of [7‘Br]-4-bromodexetimide ([7‘Br]-BDEX) was carried out by bromination via electrophilic bromodesilylation with no carrier added [76Br]NT-I4. During the preparation of this radiopharmaceutical a number of reaction conditions and reagents were examined. Oxidising agent such as peracetic acid and dichloramine-T were evaluated and found inefficient while chloramine-T appeared the reagent of choice. Peracetic acid reactions were carried out in acetic acid with radiochemical yields of 6% obtained. Dichloromi.ne~T reactions were conducted in both methanol and TFA solvent with radiochemical yields of 10% and 24% respectively. The choramine-T reactions were most efficient but were also concentration and solvent dependent. The optimum labelling conditions were found to be the use of chloramine-T (10-3M) in 0.1N HC1 at room temperature for l5 min followed by addition of a sodium metabisulte solution (fig. 1). Under these conditions the radiochemical yield reaches 80%. The purification and isolation of the radiotracer from the reaction mixture was carried out by HPLC on a µ-Bondapaku-Bondapak C18 column (300 x 7.8 mm) with a mixture of acetonitrile and ammonium acetate buffer (45:55) as the mobile phase and a ow rate of 2.5 ml/min while UV absorption was measured at 239 nm. Radiochemical and chemical purities assessed by radio-TLC and HPLC were 98% with a specific activity of 11 GBq/µmol/L.en_AU
dc.identifier.booktitleTenth International Symposium on Radiopharmaceutical Chemistry :abstracts under the auspice of Kyoto University (October 25-28, 1983)en_AU
dc.identifier.citationKassiou, M., Loc'h, C., Bottlander, M., Lambrecht, R. M., Katsifis, A., Schmidm L., Ottaviani, M., Maziere, M., & Masiere, B. (1993). Preparation and pharmacological evaluation of a new central muscarinic cholinergic receptor imaging agent [76Br]-4-bromodexetimide. Paper presented to the Tenth International Symposium on Radiopharmaceutical Chemistry, Kyoto University (October 25-28, 1983), (pp. 229-231). Kyoto, Japan : Kyoto University.en_AU
dc.identifier.conferenceenddate1983-10-28en_AU
dc.identifier.conferencenameTenth International Symposium on Radiopharmaceutical Chemistryen_AU
dc.identifier.conferenceplaceKyoto, Japanen_AU
dc.identifier.conferencestartdate1983-10-25en_AU
dc.identifier.editorsInternational Symposium on Radiopharmaceutical Chemistryen_AU
dc.identifier.pagination229-231en_AU
dc.identifier.placeofpublicationKyoto, Japanen_AU
dc.identifier.urihttps://apo.ansto.gov.au/handle/10238/16682en_AU
dc.language.isoenen_AU
dc.publisherKyoto Universityen_AU
dc.subjectPharmacologyen_AU
dc.subjectReceptorsen_AU
dc.subjectNeurologyen_AU
dc.subjectSynthesisen_AU
dc.subjectAgingen_AU
dc.subjectLabellingen_AU
dc.subjectRadiopharmaceuticalsen_AU
dc.subjectChloraminesen_AU
dc.subjectConcentration ratioen_AU
dc.subjectReagentsen_AU
dc.subjectRatsen_AU
dc.subjectRodentsen_AU
dc.subjectDataen_AU
dc.subjectCerebral cortexen_AU
dc.subjectSodiumen_AU
dc.subjectAcetonitrileen_AU
dc.subjectHippocampusen_AU
dc.titlePreparation and pharmacological evaluation of a new central muscarinic cholinergic receptor imaging agent [76Br]-4-bromodexetimideen_AU
dc.typeConference Abstracten_AU
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