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Improved synthesis of SV2A targeting radiotracer [ 11 C]UCB-J

Johanna Rokka, Eva Schlein, Jonas Eriksson

EJNMMI Radiopharm Chem. 2019 Nov 29;4(1):30.

PMID: 31784919

Abstract:

Introduction:
[11C]UCB-J is a tracer developed for PET (positron emission tomography) that has high affinity towards synaptic vesicle glycoprotein 2A (SV2A), a protein believed to participate in the regulation of neurotransmitter release in neurons and endocrine cells. The localisation of SV2A in the synaptic terminals makes it a viable target for in vivo imaging of synaptic density in the brain. Several SV2A targeting compounds have been evaluated as PET tracers, including [11C]UCB-J, with the aim to facilitate studies of synaptic density in neurological diseases. The original two-step synthesis method failed in our hands to produce sufficient amounts of [11C]UCB-J, but served as an excellent starting point for further optimizations towards a high yielding and simplified one-step method. [11C]Methyl iodide was trapped in a clear THF-water solution containing the trifluoroborate substituted precursor, potassium carbonate and palladium complex. The resulting reaction mixture was heated at 70 °C for 4 min to produce [11C]UCB-J.
Results:
After semi-preparative HPLC purification and reformulation in 10% ethanol/phosphate buffered saline, the product was obtained in 39 ± 5% radiochemical yield based on [11C]methyl iodide, corresponding to 1.8 ± 0.5 GBq at EOS. The radiochemical purity was > 99% and the molar activity was 390 ± 180 GBq/μmol at EOS. The product solution contained < 2 ppb palladium.
Conclusions:
A robust and high yielding production method has been developed for [11C]UCB-J, suitable for both preclinical and clinical PET applications.

Chemicals Related in the Paper:

Catalog Number Product Name Structure CAS Number Price
AP910251104 Potassium (tert-butoxymethyl)trifluoroborate Potassium (tert-butoxymethyl)trifluoroborate 910251-10-4 Price
LS7931444 [(tert-Butylammonio)methyl]trifluoroborate [(tert-Butylammonio)methyl]trifluoroborate Price
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