Preparation of 123I-labeled 2'-iodospiperone and imaging of D2 dopamine receptors in the human brain using SPECT.
[123I]2'-ISP was readily prepared using a radioiodine exchange reaction with a radiochemical yield of approx. 50% after HPLC purification. The radiochemical purity of the product was more than 98% and the specific activity was 5.55-11.1 GBq/mumol. Biodistribution studies performed in mice indicated that injection of [123I]2'-ISP with albumin produced a higher gastric uptake and a lower brain uptake than injection of the radioligand in a weakly acidic solution. In addition, toxicity tests performed in mice demonstrated that acute toxic effects would be very unlikely to be encountered if 2'-ISP was used for diagnostic purposes. A preliminary imaging study with [123I]2'-ISP in a healthy human volunteer showed its specific uptake by the basal ganglia, a region of the brain known to have a high density of D2 dopamine receptors.
Saji
H
H
Department of Radiopharmaceutical Chemistry, Faculty of Pharmaceutical Sciences, Kyoto University, Japan.
Iida
Y
Y
Magata
Y
Y
Yonekura
Y
Y
Iwasaki
Y
Y
Sasayama
S
S
Konishi
J
J
Nakatsuka
I
I
Shiba
K
K
Yoshitake
A
A
D000818:Animals; D001921:Brain / Q000000981:diagnostic imaging* / Q000378:metabolism; D005260:Female; D006801:Humans; D007457:Iodine Radioisotopes; D008297:Male; D051379:Mice; D008813:Mice, Inbred ICR; D017448:Receptors, Dopamine D2 / Q000378:metabolism*; D013134:Spiperone / Q000031:analogs & derivatives* / Q000138:chemical synthesis / Q000493:pharmacokinetics; D014018:Tissue Distribution; D015899:Tomography, Emission-Computed, Single-Photon
D007457:Iodine Radioisotopes; D017448:Receptors, Dopamine D2; C053751:2'-iodospiperone; D013134:Spiperone