Dataset Information

Fully-automated radiosynthesis of the amyloid tracer [¹¹C] PiB via direct [¹¹C]CO₂ fixation-reduction.

ABSTRACT:

Background

The ?-amyloid radiotracer [¹¹C] PiB is extensively used for the Positron Emission Tomography (PET) diagnosis of Alzheimer's Disease and related dementias. For clinical use, [¹¹C] PiB is produced using the ¹¹C-methylation method ([¹¹C] Methyl iodide or [¹¹C] methyl triflate as ¹¹C-methylation agents), which represents the most employed ¹¹C-labelling strategy for the synthesis of ¹¹C-radiopharmaceuticals. Recently, the use of direct [¹¹C]CO₂ fixation for the syntheses of ¹¹C-tracers has gained interest in the radiochemical community due to its importance in terms of radiochemical versatility and for permitting the direct employment of the cyclotron-produced precursor [¹¹C]CO₂. This paper presents an optimised alternative one-pot methodology of [¹¹C]CO₂ fixation-reduction for the rapid synthesis of [¹¹C] PiB using an automated commercial platform and its quality control.

Results

[¹¹C] PiB was obtained from a (25.9?±?13.2)% (Average?±?Variation Coefficient, n?=?3) (end of synthesis, decay corrected) radiochemical yield from trapped [¹¹C]CO₂ after 1?min of labelling time using PhSiH₃ / TBAF as the fixation-reduction system in Diglyme at 150?°C. The radiochemical purity was higher than 95% in all cases, and the molar activity was (61.4?±?1.6) GBq/?mol. The radiochemical yield and activity (EOS) of formulated [¹¹C] PiB from cyclotron-produced [¹¹C]CO₂ was (14.8?±?12.1)%, decay corrected) and 9.88?GBq (± 6.0%), respectively. These are higher values compared to that of the ¹¹C-methylation method with [¹¹C]CH₃OTf (~?8.3%).

Conclusions

The viability of the system PhSiH₃ / TBAF to efficiently promote the radiosynthesis of [¹¹C] PiB via direct [¹¹C]CO₂ fixation-reduction has been demonstrated. [¹¹C] PiB was obtained through a fully automated radiosynthesis with a satisfactory yield, purity and molar activity. According to the results, the one-pot methodology employed could reliably yield sufficiently high tracer amounts for preclinical and clinical use.

SUBMITTER: Buccino P

PROVIDER: S-EPMC6635575 | biostudies-literature | 2019 Jul

REPOSITORIES: biostudies-literature

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Publications

Fully-automated radiosynthesis of the amyloid tracer [11C] PiB via direct [11C]CO2 fixation-reduction.

Buccino Pablo P Savio Eduardo E Porcal Williams W

EJNMMI radiopharmacy and chemistry 20190716 1

<h4>Background</h4>The β-amyloid radiotracer [11C] PiB is extensively used for the Positron Emission Tomography (PET) diagnosis of Alzheimer's Disease and related dementias. For clinical use, [11C] PiB is produced using the 11C-methylation method ([11C] Methyl iodide or [11C] methyl triflate as 11C-methylation agents), which represents the most employed 11C-labelling strategy for the synthesis of 11C-radiopha ...[more]

PMID: 31659494

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