Biodistribution of two (131)I-IMBA preparations, differently labelled, in mice with experimental B16 melanoma tumours.
BACKGROUND
Numerous reports indicate that some iodinated compounds of benzamide derivatives display a strong affinity to the cells of melanoma. In the present report, a compound [N-(2-diethylaminoethyl)-3-iodo-4metyoxybenzamide ((131)I-IMBA)] has been prepared by two different labelling methods. Biodistribution of the injected compound was followed in mice with experimentally induced B16 melanoma tumours, and tumour/ tissue ratios were studied as a function of time post administration.


METHODS
The iodinated (131)I-IMBA was obtained by means of (131)I exchange for nonradioactive iodine atoms (method I) and by means of (131)I substitution for a metalorganic group (method II). The last preparation was purified by chloroform extraction. The chemical purity was assessed by means of ascending thin layer chromatography (TLC). The biodistribution of (131)I-IMBA in C57 Black mice was studied in animals with experimentally induced B16 mice melanoma tumours.


RESULTS
The mean labelling efficiency exceeded 95 and 80 % for methods I and II, respectively, at radiochemical purity > 95% in both cases. (131)I-IMBA was vividly cumulated by melanoma tumours in mice. At 24-hours post (131)I-IMBA administration the values of tumour /non-tumour ratios for the compound labelled by method II reached the following values: tumour/liver 10 +/- 3, tumour/lung 15 +/- 12, tumour/blood 153 +/- 39, tumour/intestines 176 +/- 26, tumour/kidneys 270 +/- 107, and tumour/muscle 448 +/- 82. These values exceeded, by an order of magnitude, the corresponding ratios for the same compound labelled by method I.


CONCLUSIONS
High values of tumour/non-tumour ratios indicate that (131)I-IMBA could be a promising radiopharmaceutical for clinical diagnosis (staging) of melanomas in humans.
Janczak
Michał
M
Department of Nuclear Medicine, Medical University of Lodz, Czechoslowacka, Łódź, Poland. sandman@csk.umed.lodz.pl
Kapuściński
Janusz
J
Olasik
Elzbieta Mikiciuk-
EM
Rózalski
Marek
M
Płachcińska
Anna
A
Kuśmierek
Jacek
J
D000818:Animals; D001549:Benzamides / Q000737:chemistry / Q000493:pharmacokinetics*; D045744:Cell Line, Tumor; D005260:Female; D007462:Iodobenzenes / Q000737:chemistry / Q000493:pharmacokinetics*; D008545:Melanoma / Q000000981:diagnostic imaging* / Q000378:metabolism*; D008657:Metabolic Clearance Rate; D051379:Mice; D008810:Mice, Inbred C57BL; D009928:Organ Specificity; D011877:Radionuclide Imaging; D019275:Radiopharmaceuticals / Q000138:chemical synthesis / Q000493:pharmacokinetics; D014018:Tissue Distribution; D051598:Whole Body Imaging / Q000379:methods*
D001549:Benzamides; D007462:Iodobenzenes; C415568:N-(2-diethylaminoethyl)-3-iodo-4-methoxybenzamide; D019275:Radiopharmaceuticals