Therapeutic 188Re-lanreotide: determination of radiopharmacokinetic parameters in rats.
OBJECTIVE
The radiopharmacokinetic parameters of the therapeutic radiopharmaceutical (188)Re-lanreotide were compared in rats implanted with hepatocarcinoma tumours (n= 18) and healthy rats (n= 18).


METHODS
Rats were injected with approximately 1.8 MBq (188)Re-lanreotide (0.1 ml) via the tail vein and blood samples were obtained. The activity per gram of tissue (%IA/g) was calculated and the radiopharmacokinetic parameters determined. Data were fitted using a two-compartment model.


RESULTS
Significant differences were found between healthy and hepatoma rats for beta elimination half-life (22.56 vs 48.14 h); transference constants K(10) (k(e)) (6.44 vs 3.05 h(-1)) and K(12) (2.76 vs 7.09 h(-1)); volume of distribution (2.06 vs 5.45 ml); mean residence time (66.58 vs 95.50 h) and apparent volume of distribution at steady state (131.30 vs 810.37 ml). The tumour/organ ratios after 24 h were 11.20 for tumour/muscle, 8.00 for tumour/liver and 7.72 for tumour/bone. The scintigraphic images obtained therefore had high resolution.


CONCLUSIONS
(188)Re-lanreotide had a prolonged beta elimination half-life and increased volume of distribution in rats with hepatocellular carcinoma. This may be beneficial in the diagnosis and therapy of metastatic lesions in patients with cancer.
Molina-Trinidad
Eva M
EM
Departamento de Ingeniería y Tecnología (Biofarmacia), Facultad de Estudios Superiores Cuautitlán, Estado de México, México. mariaeva_molina@yahoo.com.mx
de Murphy
Consuelo Arteaga
CA
Jung-Cook
Helgi
H
Stack
Eduardo Murphy
EM
Pedraza-Lopez
Martha
M
Morales-Marquez
José Luis
JL
Serrano
Guadalupe Vertiz
GV
D000818:Animals; D000970:Antineoplastic Agents / Q000493:pharmacokinetics* / Q000627:therapeutic use; D001842:Bone and Bones; D006528:Carcinoma, Hepatocellular / Q000000981:diagnostic imaging / Q000188:drug therapy / Q000378:metabolism* / Q000532:radiotherapy; D006207:Half-Life; D008099:Liver; D008113:Liver Neoplasms / Q000000981:diagnostic imaging / Q000188:drug therapy / Q000378:metabolism* / Q000532:radiotherapy; D008297:Male; D009132:Muscles; D010456:Peptides, Cyclic / Q000493:pharmacokinetics* / Q000627:therapeutic use; D011868:Radioisotopes / Q000493:pharmacokinetics / Q000627:therapeutic use; D011877:Radionuclide Imaging; D019275:Radiopharmaceuticals / Q000493:pharmacokinetics* / Q000627:therapeutic use; D051381:Rats; D017208:Rats, Wistar; D012016:Reference Values; D012211:Rhenium / Q000493:pharmacokinetics* / Q000627:therapeutic use; D013004:Somatostatin / Q000031:analogs & derivatives* / Q000493:pharmacokinetics / Q000627:therapeutic use; D014018:Tissue Distribution
D000970:Antineoplastic Agents; D010456:Peptides, Cyclic; D011868:Radioisotopes; D019275:Radiopharmaceuticals; C060347:lanreotide; D013004:Somatostatin; D012211:Rhenium