title: Metabolism of [123I]epidepride may affect brain dopamine D2 receptor imaging with single-photon emission tomography.
abstract: Iodine-123 labelled epidepride is a novel radiopharmaceutical for the study of cerebral dopamine D2 receptors using single-photon emission tomography (SPET). A lipophilic labelled metabolite of [123I]epidepride which may enter the brain and hamper the quantitation of receptors has been observed in human plasma. In the present study, gradient high-performance liquid chromatography (HPLC) was used to investigate the plasma concentration of the lipophilic labelled metabolite and its correlation to SPET imaging of striatal dopamine D2 receptors. A linear regression fit showed a negative correlation between the amount of the lipophilic labelled metabolite and the striatum to cerebellum ratio (n=16, R=-0.58, P<0.02), suggesting that plasma metabolite analysis is essential when imaging dopamine D2 receptors with SPET using [123I]epidepride.
authors.affiliation: Department of Clinical Physiology and Nuclear Medicine, Kuopio University Hospital, Finland.
authors.forename: K A
authors.initials: KA
authors.lastname: Bergström
authors.forename: M
authors.initials: M
authors.lastname: Yu
authors.forename: J T
authors.initials: JT
authors.lastname: Kuikka
authors.forename: K K
authors.initials: KK
authors.lastname: Akerman
authors.forename: J
authors.initials: J
authors.lastname: Hiltunen
authors.forename: J
authors.initials: J
authors.lastname: Lehtonen
authors.forename: C
authors.initials: C
authors.lastname: Halldin
authors.forename: J
authors.initials: J
authors.lastname: Tiihonen
mesh_terms: D000328:Adult; D001549:Benzamides / Q000493:pharmacokinetics; D001812:Blood-Brain Barrier; D001921:Brain / Q000000981:diagnostic imaging* / Q000378:metabolism; D002851:Chromatography, High Pressure Liquid; D003287:Contrast Media; D018492:Dopamine Antagonists / Q000493:pharmacokinetics; D006801:Humans; D007457:Iodine Radioisotopes; D008297:Male; D011759:Pyrrolidines / Q000493:pharmacokinetics; D019275:Radiopharmaceuticals / Q000493:pharmacokinetics; D017448:Receptors, Dopamine D2 / Q000378:metabolism*; D012457:Salicylamides / Q000493:pharmacokinetics; D015899:Tomography, Emission-Computed, Single-Photon
chemical_list: D001549:Benzamides; D003287:Contrast Media; D018492:Dopamine Antagonists; D007457:Iodine Radioisotopes; D011759:Pyrrolidines; D019275:Radiopharmaceuticals; D017448:Receptors, Dopamine D2; D012457:Salicylamides; C065065:FLB 457; C063525:epidepride