To study pharmacokinetics of 99m Tc-PQQ ester（99m Tc-4

5-dioxo-4

5-dihydro-1H-pyrrolo（2

3-f） quinoline-2

7

9-tricarboxylic acid 2-ethyl ester 7

9-dimethyl ester） in the blood and the brain of mice with pharmacokinetics local model and vector analysis.99m Tc-PQQ ester can be used to image NMDA receptor.99m Tc-PQQ ester（0.2 mL

10 MBq） was injected through tail vein into the mice（18-22 g）

which were divided into 8 groups（five per group

one group for the blood and the other for the brain） randomly.10 μL blood samples were withdrawn from the tail vein at 5

15

30

60

120

180 and 360 min post-injection.The other groups of mice were sacrificed at the same time intervals post-injection

and tissues of the brain（thalamencephalon

hippocampus

frontal cortex

parietal cortex

temporal cortex

occipital cortex

pons and medulla oblongata

striatum and cerebellum） were removed and weighed.Radioactivities were counted with the γ-counter.Kinetic equations and parameters were calculated by pharmacokinetics local model

and pharmacokinetics data were studied by solution space and vector analysis method.Experimental data showed that 99m Tc-PQQ ester could accumulated in the hippocampus

frontal cortex and parietal cortex.According to the calculation of pharmacokinetics local model

kinetic equations were: hippocampus C=0.24e 0.0420t +0.28e 0.00446t

frontal cortex C=0.22e 0.0420t +0.27e 0.00446t

parietal cortex C=0.24e 0.0420t +0.21e 0.00446t

cerebellum C=0.23e 0.0420t +0.11e 0.00446t

occipital cortex C=0.17e 0.0420t +0.14e 0.00446t

striatum C= 0.11e 0.0420t +0.17e 0.00446t

pons and medulla oblongata C=0.10e 0.0420t +0.18e 0.00446t

temporal cortex C= 0.14e 0.0420t +0.14e 0.00446t and thalamencephalon C=0.14e 0.0420t +0.09e 0.00446t

respectively.Pharmacokinetics parameters of the blood were also calculated

k 12 0.0173 min 1

k 21 0.0096 min 1

k e 0.0196 min 1

CL 0.13 ID%g 1 min 1

AUC 753.68 ID%g 1 min

t 1/2α 16.50min and t 1/2β 155.35 min

respectively.There was a linear relationship between vector modules corresponding to brain tissues and the highest concentrations of 99m Tc-PQQ ester in the brain tissues

and the linear regression equation was y=1.3287x 0.0229

R 2 =0.9487.Results of solution space and vector analysis method indicated that kinetic action of 99m Tc-PQQ ester in the hippocampus

frontal cortex and parietal cortex was similar

and was different from that of the other brain tissues.The study of pharmacokinetics shown that 99m Tc-PQQ ester can accumulated in some brain tissues of mice

such as hippocampus

frontal cortex and parietal cortex.The favourable uptake and suitable retention in these brain tissues confirmed that it can combine with NMDA receptor in vivo.