To study the pharmacokinetics of 99mTc labeled N-[2-(N-(2-mercapotoethyl))aminoformylmethyl]-N-(2-mercapotoethyl)-3

5-dimethyladamantyl aminoacetamide (99mTc-NCAM)

an N-methyl-D-aspartate (NMDA) receptor inhibitor

in brain tissues of mice

0.2 mL (7.4 MBq) 99mTc-NCAM was injected via tail vein into groups of KM mice. The mice were sacrificed by decapitation at 5

10

30

60

120 or 180 min postinjection. Pallium

striatum

hippocampus

cerebellum and thalamencephalon were collected and weighed

and radioactivities were counted. The mouse blood samples of 20 μL were taken and counted at the same time points. Pharmacokinetics of 99mTc-NCAM in blood was analyzed with a pharmacokinetics local model. 99mTc-NCAM accumulated quickly into the brain of mice after injection

and high uptake was observed in pallium and hippocampus with the maximum values of 1.51±0.13 %ID/g and 0.74±0.002 %ID/g

respectively. Theoretical calculation indicated that pharmacokinetics of 99mTc-NCAM in mice fit into a two-compartmental model

and pharmacokinetic equations and parameters of brain tissues and blood were obtained. 99mTc-NCAM can penetrate the blood-brain barrier into brain regions

and high uptakes were observed in high NMDA receptor expressing tissues such as pallium and hippocampus. 99mTc-NCAM may be a potential NMDA receptor imaging agent and could be used in diagnoses and prognosis monitoring for some neurodegenerative diseases.