title: HPLC and TLC methods for analysis of [18F]FDG and its metabolites from biological samples.
abstract: The most used positron emission tomography (PET) tracer, 2-[18F]fluoro-2-deoxy-d-glucose ([18F]FDG), is a glucose analogue that is used to measure tissue glucose consumption. Traditionally, the Sokoloff model is the basis for [18F]FDG modeling. According to this model, [18F]FDG is expected to be trapped in a cell in the form of [18F]FDG-6-phosphate ([18F]FDG-6-P). However, several studies have shown that in tissues, [18F]FDG metabolism goes beyond [18F]FDG-6-P. Our aim was to develop radioHPLC and radioTLC methods for analysis of [18F]FDG metabolites from tissue samples. The radioHPLC method uses a sensitive on-line scintillation detector to detect radioactivity, and the radioTLC method employs digital autoradiography to detect the radioactivity distribution on a TLC plate. The HPLC and TLC methods were developed using enzymatically in vitro-produced metabolites of [18F]FDG as reference standards. For this purpose, three [18F]FDG metabolites were synthesized: [18F]FDG-6-P, [18F]FD-PGL, and [18F]FDG-1,6-P2. The two methods were evaluated by analyzing the [18F]FDG metabolic profile from rodent ex vivo tissue homogenates. The HPLC method with an on-line scintillation detector had a wide linearity in a range of 5Bq-5kBq (LOD 46Bq, LOQ 139Bq) and a good resolution (Rs ≥1.9), and separated [18F]FDG and its metabolites clearly. The TLC method combined with digital autoradiography had a high sensitivity in a wide range of radioactivity (0.1Bq-2kBq, LOD 0.24Bq, LOQ 0.31Bq), and multiple samples could be analyzed simultaneously. As our test and the method validation with ex vivo samples showed, both methods are useful, and at best they complement each other in analysis of [18F]FDG and its radioactive metabolites from biological samples.
authors.affiliation: Turku PET Centre, Preclinical Imaging, University of Turku, Turku, Finland; Turku PET Centre, Radiopharmaceutical Chemistry Laboratory, University of Turku, Turku, Finland. Electronic address: johanna.rokka@utu.fi.
authors.forename: Johanna
authors.initials: J
authors.lastname: Rokka
authors.affiliation: Turku PET Centre, Preclinical Imaging, University of Turku, Turku, Finland; MediCity Research Laboratory, University of Turku, Turku, Finland.
authors.forename: Tove J
authors.initials: TJ
authors.lastname: Grönroos
authors.affiliation: Turku PET Centre, Radiopharmaceutical Chemistry Laboratory, University of Turku, Turku, Finland.
authors.forename: Tapio
authors.initials: T
authors.lastname: Viljanen
authors.affiliation: Turku PET Centre, Radiopharmaceutical Chemistry Laboratory, University of Turku, Turku, Finland; Turku PET Centre, Accelerator Laboratory, Åbo Akademi University, Turku, Finland; Department of Chemistry, University of Turku, Turku, Finland.
authors.forename: Olof
authors.initials: O
authors.lastname: Solin
authors.affiliation: Turku PET Centre, Preclinical Imaging, University of Turku, Turku, Finland; MediCity Research Laboratory, University of Turku, Turku, Finland.
authors.forename: Merja
authors.initials: M
authors.lastname: Haaparanta-Solin
mesh_terms: D000818:Animals; D001921:Brain / Q000378:metabolism*; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D002855:Chromatography, Thin Layer / Q000379:methods*; D019788:Fluorodeoxyglucose F18 / Q000032:analysis / Q000378:metabolism*; D057230:Limit of Detection; D008099:Liver / Q000378:metabolism*; D008297:Male; D055442:Metabolome; D008810:Mice, Inbred C57BL; D049268:Positron-Emission Tomography; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D019788:Fluorodeoxyglucose F18
keywords: HPLC; TLC; [(18)F]FD-PGL; [(18)F]FDG; [(18)F]FDG-1,6-P2; [(18)F]FDG-6-P