TY - JOUR
T1 - Microwave-assisted radiosynthesis of [18F]fluorinated fatty acid analogs
AU - Belanger, Anthony P.
AU - Pandey, Mukesh K.
AU - Degrado, Timothy R.
N1 - Funding Information:
The authors wish to acknowledge CEM for providing a PETWave demo unit to carry out our initial studies and the support of NIH ( CA-108620 ).
PY - 2011/4
Y1 - 2011/4
N2 - Microwave reactors remain largely underutilized in the field of positron emission tomography (PET) chemistry. This is particularly unfortunate since microwave synthesis elegantly addresses two of the most critical issues of PET radiochemistry with short-lived radionuclides: reaction rate and side-product formation. In this study, we investigate the efficiency of synthesis of terminally [18F]fluorinated fatty acid analogs using a commercial microwave reactor in comparison with conventional heating (CH). Methods: The labeling precursors were methyl esters of terminally substituted alkyl bromides and iodides. Duration and temperatures of the [18F]fluorination reaction were varied. Chemical and radiochemical purities, and radiochemical yields were investigated for conventional (CH) and microwave-assisted (MW) radiosyntheses. Results: The results demonstrate that microwave heating enhanced [18F]fluoride incorporation to >95% (up to 55% improvement), while reducing reaction times to 2 min (~10-fold reduction) or temperatures to 55-60°C (20°C reduction). Overall decay-corrected radiochemical yields of purified [18F]fluoro fatty acids were higher (MW=49.0±4.5%, CH=23.6±3.5%, P<05) with microwave heating and side-products were notably fewer. Conclusion: For routine synthesis of [18F]fluoro fatty acid analogs, microwave heating is faster, milder, cleaner, less variable and higher yielding than CH and therefore the preferred reaction method.
AB - Microwave reactors remain largely underutilized in the field of positron emission tomography (PET) chemistry. This is particularly unfortunate since microwave synthesis elegantly addresses two of the most critical issues of PET radiochemistry with short-lived radionuclides: reaction rate and side-product formation. In this study, we investigate the efficiency of synthesis of terminally [18F]fluorinated fatty acid analogs using a commercial microwave reactor in comparison with conventional heating (CH). Methods: The labeling precursors were methyl esters of terminally substituted alkyl bromides and iodides. Duration and temperatures of the [18F]fluorination reaction were varied. Chemical and radiochemical purities, and radiochemical yields were investigated for conventional (CH) and microwave-assisted (MW) radiosyntheses. Results: The results demonstrate that microwave heating enhanced [18F]fluoride incorporation to >95% (up to 55% improvement), while reducing reaction times to 2 min (~10-fold reduction) or temperatures to 55-60°C (20°C reduction). Overall decay-corrected radiochemical yields of purified [18F]fluoro fatty acids were higher (MW=49.0±4.5%, CH=23.6±3.5%, P<05) with microwave heating and side-products were notably fewer. Conclusion: For routine synthesis of [18F]fluoro fatty acid analogs, microwave heating is faster, milder, cleaner, less variable and higher yielding than CH and therefore the preferred reaction method.
KW - Microwave-assisted [F]fluorination
KW - PET
KW - [F]fluoro fatty acid
UR - http://www.scopus.com/inward/record.url?scp=79954418712&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=79954418712&partnerID=8YFLogxK
U2 - 10.1016/j.nucmedbio.2010.10.001
DO - 10.1016/j.nucmedbio.2010.10.001
M3 - Article
C2 - 21492792
AN - SCOPUS:79954418712
SN - 0969-8051
VL - 38
SP - 435
EP - 441
JO - Nuclear Medicine and Biology
JF - Nuclear Medicine and Biology
IS - 3
ER -