PT  - JOURNAL ARTICLE
AU  - Moon, Byung Seok
AU  - Park, Jun Hyung
AU  - Lee, Hong Jin
AU  - Kil, Hee Sup
AU  - Chi, Dae Yoon
AU  - Lee, Byung Chul
AU  - Kim, Yu Kyeong
AU  - Kim, Sang Eun
TI  - Highly efficient production of [<sup>18</sup>F]fallypride with low concentration of base
DP  - 2010 May 01
TA  - Journal of Nuclear Medicine
PG  - 1502--1502
VI  - 51
IP  - supplement 2
4099  - http://jnm.snmjournals.org/content/51/supplement_2/1502.short
4100  - http://jnm.snmjournals.org/content/51/supplement_2/1502.full
SO  - J Nucl Med2010 May 01; 51
AB  - 1502 Objectives [18F]Fallypride exhibits an effective radiotracer for the study of dopamine D2/D3 receptor occupancy, neuropsychiatric disorders and aging in humans. However, automated labeling efficiency showed moderate radiochemical yields about 5-40% with relatively long incorporation time of fluorine-18, preceded high temperatures (150-165 °C) or involved the use of an unusual microwave system in automatic devices. In present study, we describe an automated radiochemical synthesis of [18F]fallypride in different base concentration and incorporation time of fluorine-18 for potentially utilizable in routine production sites. Methods To minimization of base concentration of phase-transfer catalyst, [18F]fluoride was extracted with different concentrations of tetrabutylammonium bicarbonate (TBAHCO3) or Kryptofix 2.2.2./K2CO3 in organic solvent such as CH3CN/H2O or MeOH/H2O from 18O-enriched water trapped on the activated ion exchange cartridge (Chromafix® PS-HCO3). After azeotropic drying, the labeling reaction proceeded in CH3CN at 100 °C for 10 or 30 min. The desired product, [18F]fallypride, was purified by reverse phase HPLC and collected solution was exchanged for 10% ethanol in saline using tC18 Sep-Pak for clinical research. Results The radiochemical yield was increased according to decreasing amounts of base concentration. The labeling condition of [18F]fallypride was optimized that 2 mg of tosyl-fallypride in acetonitrile (1 mL) was heated at 100 °C for 10 min with 40% TBAHCO3 (10 μL). [18F]Fallypride was obtained with high radiochemical yield about 68 ± 1.6% (decay-corrected, n = 8) within 51 ± 1.2 min including HPLC purification and solid-phase purification. The specific activity showed about 140-192 GBq/μmol. Conclusions [18F]Fallypride was prepared with a significantly improved radiochemical yield with high specific activity and shorten synthetic time. This automated procedure for [18F]fallypride production could facilitate its routine clinical use in dopamine D2/D3 studies