RESUMO
Objective To establish an automatic synthesis method for 11C-carfentanil (CFN) as an novel opiate receptor radioligand and study its biodistribution in rats. Methods 11C-Triflate-CH3 was bubbled into 0.5 mg precursor desmethyl-CFN (which was dissolved in 0.15 ml DMSO) to generate 11C-CFN in a V-tube at room temperature. Sep-Pak C2 column was used for purification of 11C-CFN, which was eluted by 3ml binary system aqueous solution, 10 ml water thrice, and then I ml ethanol. The biodistribution (% ID/g) of 11C-CFN in SD rats was studied. SPSS 13.0 was used for statistical analysis. Non-normal distribution data were analyzed using nonparametric test. Results The synthesis time for 11C-CFN was 20 min (end of bombardment, EOB). The synthesis yield was (35.5 ± 2.2) % on average (n = 12, uncorrected)with the radiochemical purity over 98%. Biodistribution study in rats showed that the tracer had a high brain uptake, rapid blood clearance, and a metabolic pathway via liver and kidney. The highest tracer uptake was in thalamus (4.26 ± 0.89) % ID/g and striatum (4.05 ± 1.08) % ID/g at 5 min after injection, followed by cerebral cortex (2.63±0.89) %ID/g, pons (2.26 ±0.57) % ID/g, hippocampus (2. 17 ±0.55) %ID/g and cerebellum (2. 15 ±0.39) %ID/g. Conclusions The automatic synthesis of 11C-CFN is fast and reliable, and this radioligand can be used for opiate receptor imaging.
RESUMO
Objective HupA is one of the potential drugs which can be used to treat Alzheimer's disease(AD).The aim of this study was to explore the pharmacokinetics and biodistribution of HupA in vivo by using 11C-HupA.Methods A total of 25 SD rats were studied.They were divided into 5 groups (5 rats in each group).All had intravenous injection of 22 MBq(in0.2 ml)11C-HupA through tail vein.Dynamic im-aging Was acquired from 5 to 90 minutes after injection.Venous blood and organ activities were collected at 5,15,30,60.and 90 minutes after injection.Percentage activity of injected dose per gram of tissue(%ID/g)was calculated to characterize the biodistribution of tracer in different brain regions: frontal,apical, temporal,occipital,cerebellum,hippocampus,striatum,thalamencephalon, and brain stem, Variance analysis using SPSS 11.5 software was performed and compared among the study groups.Results 11C-HupA was character-istic for its quick clearance from blood,with half time T1/2 of (14.61±1.77) min,and clearance rate (CL)macokinetics of 11C-HupA in rats corresponded to a one-compartment model.with an activity curve(area 11C-HupA distribution in different brain regions,being greater in cerebral cortex,hippocampus,hypothala-mus and brain stem. Conclusions Pharmacokinetic study of 11C-HupA in brain was fast.convenient and showed high specificity and sensitivity.Its ability to quantitatively evaluate brain function and its character-istic distribution in mice provided some evidence for monitoring therapy in AD patients.