Fully automated synthesis and purification of 4-(2\u27-methoxyphenyl)-1-[2\u27-(N-2\u27\u27-pyridinyl)- p-[18F]fluorobenzamido]ethylpiperazine

We have developed an efficient synthesis method for the rapid and high-yield automated synthesis of 4-(2\u27-methoxyphenyl)-1-[2\u27-(N-2"-pyridinyl)-p-[18F]fluorobenzamido]ethylpiperazine (p-[18F]MPPF). No-carrier-added [18F]F1 was trapped on a smallQMA cartridge and eluted with 70% MeCN(aq) (0.4 mL) containing Kryptofix 222 (2.3 mg) and K2CO3 (0.7 mg). The nucleophilic[18F]fluorination was performed with 3mg of the nitro-precursor in DMSO (0.4 mL) at 190 C for 20 min, followed by thepreparative HPLC purification (column: COSMOSIL Cholester, Nacalai Tesque, Kyoto, Japan; mobile phase: MeCN/25mMAcONH4/AcOH = 200/300/0.15; flow rate: 6.0 mL/min) to afford p-[18F]MPPF (retention time = 9.5 min). p-[18F]MPPF wasobtained automatically with a radiochemical yield of 38.6 5.0% (decay corrected, n = 5), a specific activity of 214.3 21.1GBq/mmol, and a radiochemical purity of >99% within a total synthesis time of about 55 min

Automatic synthesis of L-[beta-11C]amino acids using an immobilized enzyme column

We have developed a system for the automatic synthesis of L-[beta-11C]amino acids for i.v.injection by means of enzyme-mediated reactions from 11CO2 via 11CH3I and D,L-[beta-11C]alanine as labeled intermediates. This system, which incorporates an ultrafilter cartridge sterilized by electron beam irradiation and a column packed with immobilized enzymes, was effective for eliminating enzymes and endotoxins that may contaminate the product. Using this system, 1.3+/-0.5GBq of 5-hydroxy-L-[beta-11C]tryptophan with a radiochemical purity of 97.1+/-0.6% and a specific activity of 39.6+/-8 GBq/mumol a pH value of 4 could be obtained in about 32 min(n=3,at EOS). No endotoxin, enzyme, or bacteria was detected in the product. L-[beta-11C} dihydroxyphenylalanine (L-[beta-11C]DOPA) was also synthesized using this system

High-yield automated synthesis of[18F]fluoroazomycin arabinoside([18F]FAZA) for hypoxia-specific tumor imaging

The aimofthisstudywastodevelopanefficientfullyautomatedsynthesismethodtoachieveahighradiochemicalyieldof[18F]FAZA withasmallamountofprecursor.Asmallcartridgecontaining25mgoftheQMAresinwaspreparedandevaluatedtoobtain[18F]F1 in asmallquantityofbase(K2CO3), whichmight allowtheuseofasmallamountofprecursor. Thelabelingandhydrolyzingconditionsfor[18F]FAZAsynthesiswerealsoinvestigatedmanually.No-carrier-added[18F]F1 was trappedonthesmallQMAcartridgeandelutedwithamixtureofKrytofix222(2.26mg,6.0 mmol)andK2CO3 (0.69 mg,5.0 mmol)in70%MeCN(0.4mL).Theautomatedsynthesisof[18F]FAZA wasoptimallyperformedwithamodifiedNIRSoriginalsynthesissystemforclinicaluse,bylabeling2.5mg(5.2 mmol)oftheprecursorinDMSO(0.4mL)at120 1C for10min,andthenbyhydrolyzingthe 18F-labeledintermediatewith0.1MNaOH(0.5mL)atroomtemperaturefor3min.Usingtheabovecondition,the[18F]FAZAinjectionwasobtainedwithahighradiochemicalyieldof52.475.3%(decay-corrected, n¼8) within50.571.5min