Pharmacokinetics Of 125-i-labelled Meta-iodo-benzyl-guanidine (mibg) On Nmri Mice And Wistar Rats

The study of some pharmacokinetics providing the mechanism of uptake and metabolism parameters for the 125-mIBG is described. NMRI mice are used for plasma binding study; the animals are killed by decapitation after intravenously (IV) injection of 125-I-mIBG. Wistar rats are used in urinary excretion study. After IV injection, animals are placed in metabolic cages to collect urine. For biodistribution, the rats are killed at different time intervals. The considered organs are removed. The radioactivity of all parameters was performed by gamma counter. The results show that the blood clearance is very high after several hours post injection. The plasma binding is very low one hour post injection and very high after 72 hours. Furthermore, we observe a rapid excretion of radioactivity 24 hours post injection. However, we observe that 72 hours after injection, the radioactivity is important relatively. Concerning the bio distribution, the radioactivity per gram of different organs was normalized according to the adrenal glands. Also, we note, the adrenal glands may be the only target organs 48 hours post injection. These results confirm that 125-I-mIBG has a high affinity for the adrenergic innervation›s organs (adrenal glands, salivary glands, heart and spleen).