RESUMO
The incorporation of thallium-201 into 8-hydroxyquinoline was targeted for cell labeling due to interesting physical properties and wide availability of this nuclide as a single photon emission computed tomography [SPECT] radionuclide. Thallium-201 [T[1/2]=3.04 d] in Tl[+] form was converted to Tl[3+] cation in presence of O[3]/6M HCl and di-isopropyl ether, controlled by radiothin layer chromatography [RTLC] /gel electrophoresis methods. The final evaporated activity reacted with ethanolic 8-hydroxy-quinoline [oxine] solution in normal saline to yield [[201]Tl][III] oxinate at room temperature after 0.5 h, followed by solid phase extraction/purification using C18 Sep-Pak column and partition coefficient determination for water/lipid solubility. In vitro red blood cell [RBC] labeling was also performed. A radiochemical yield of more than 95% was obtained. Radiochemical purity of 92% was obtained using RTLC [>90% using HPLC] with specific activity of about 820 GBq/mmol. The tracer was stable in the final product and in presence of human serum at 37°C up to 6h. The partition coefficient of lopP=5.5 was obtained. The labeled compound was used in RBC labeling. The cell uptake ratio was 0.47 after 240 min. [[201]Tl][III] oxinate used in this study is a widely available agent for use in RBC labeling studies in biology, medicine and various other research areas