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10-[(11)C]methoxy-20(S)-camptothecin was synthesized automatically. The radiochemical yield was 30%-50% (all calculated at EOB, n=20) with [(11)C]methyl triflate as a methylating agent. The radiochemical purity was greater than 96%, and the specific activity was 8.72±2.18 GBq/μmoL at EOS. Biodistribution showed that 10-[(11)C]methoxy-20(S)-camptothecin is characterized by quick clearance from the blood and by significant uptake in the liver (5.72±1.92% ID/g at 15 min), intestines (2.43±0.38% ID/g at 15 min), and kidney (1.57±0.85% ID/g at 15 min). Micro-PET imaging clearly showed high radioactivity accumulation in liver, intestines and bladder, indicating that the primary modes of excretion of the radiotracer are through the hepatobiliary system and, to a lesser extent, through the renal system., (Copyright © 2012 Elsevier Ltd. All rights reserved.)

The preparation of 10-(2-[F]fluoroethoxy)-20( S)-camptothecin, a potential positron emission tomography tracer for the imaging of topoisomerase I in cancers, is described. 10-(2-[F]Fluoroethoxy)-20( S)-camptothecin was synthesized by the [F]fluoroalkylation of the corresponding hydroxy precursor molecule with 2-[F]fluoroethyl bromide ([F]FEtBr) in dimethylsulfoxide (DMSO) at 55 °C for 20 min; this was followed by purification using high performance liquid chromatography (HPLC) with a total preparation time of 60 min. The overall radiochemical yield was approximately 5.4-12 % (uncorrected), and the radiochemical purity was above 96 %. [ABSTRACT FROM AUTHOR]

Abstract: 10-[11C]methoxy-20(S)-camptothecin was synthesized automatically. The radiochemical yield was 30%–50% (all calculated at EOB, n=20) with [11C]methyl triflate as a methylating agent. The radiochemical purity was greater than 96%, and the specific activity was 8.72±2.18GBq/μmoL at EOS. Biodistribution showed that 10-[11C]methoxy-20(S)-camptothecin is characterized by quick clearance from the blood and by significant uptake in the liver (5.72±1.92% ID/g at 15min), intestines (2.43±0.38% ID/g at 15min), and kidney (1.57±0.85% ID/g at 15min). Micro-PET imaging clearly showed high radioactivity accumulation in liver, intestines and bladder, indicating that the primary modes of excretion of the radiotracer are through the hepatobiliary system and, to a lesser extent, through the renal system. [Copyright &y& Elsevier]