Synthesis and quality control of [11C]Deuterodeprenyl using the automated module General Electric (GE) TRACERlab® FX C Pro

Objectives [11C]Deuterodeprenyl ([11C]DED) is a reference radiotracer for the quantification of the activity of MAO-B by means of PET. This radiotracer has shown to be useful in the in vivo evaluation of neurological pathologies in which an overexpression of the glial MAO-B enzyme is found: Alzheimer disease, Creutzfeldt-Jacob disease, Temporal Lobe Epilepsy, among others. The purpose of this study was the optimization of the synthesis of [11C]Deuterodeprenyl on an automated synthetic platform and its quality control.

Methods Synthetic process begins with the production of [11C]CO2 in cyclotron (GE PETtrace 16.5MeV) via the 14N(p, α)11C nuclear reaction. [11C]CO2 was delivered from the target to the module, and trapped for purification and further reduction to [11C]CH4, which suffers iodination to yield [11C]CH3I. This is later converted into [11C]CH3OTf, which reacts with N-desmethyl-(R)-α,α-dideuterodeprenyl in butanone, 1 min at 80 C. Crude product is separated using HPLC, purified through SPE and formulated in saline. Quality control (QC) tests include appearance of solution, pH, residual solvents control (GC), chemical and radiochemical purity control (HPLC), radionucleidic purity and identity, and specific activity (SA). Microbiological purity is also evaluated.

Results Full compliance with the established specifications was achieved for the produced radiotracer. EOS activity for [11C]DED ranged between 3.9 - 4.4 GBq (Radiochemical Yield from [11C]CO2: 2.1-2.4% ndc). SA is in the range 75-88 GBq/umol. Total synthesis time was 35 min (including purification and formulation) and QC analyses were carried out in 15 min. Two simultaneous PET scans could be acquired with one batch of this radiotracer.

Conclusions A methodology for the production of [11C]DED using the automated synthetic platform TRACERlab FX C Pro has been developed. This methodology enables to produce injectable [11C]DED if GMP guidelines are followed, in agreement with both USP or EP specifications, or literature data.

Research Support PEDECIBA Química