Premium
L‐[2‐RADIOIODO]‐Tyrosine a potential tumour tracer for spect. Radiosynthesis, in vitro and in vivo evaluation
Author(s) -
Mertens J.,
Iterbeke K.,
Lahoutte T.,
Joos C.,
Tourwé D.,
Bossuyt A.
Publication year - 2001
Publication title -
journal of labelled compounds and radiopharmaceuticals
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.432
H-Index - 47
eISSN - 1099-1344
pISSN - 0362-4803
DOI - 10.1002/jlcr.25804401302
Subject(s) - radiosynthesis , chemistry , in vivo , in vitro , labelling , tyrosine , radiochemistry , specific activity , pharmacophore , hydrolysis , efflux , tracer , stereochemistry , biochemistry , enzyme , physics , microbiology and biotechnology , nuclear physics , biology
The pharmacophore L‐2‐Br‐tyrosine (2‐Br‐T) was obtained by a stereospecific synthesis in which benzophenonimine glycinesultame, sodium hexamethyldisilane and O‐(methoxycarbonyl)‐3‐bromo‐4‐bromo ethylphenol are successively coupled followed by hydrolysis. Radioiodination (N.C.A. 123/125 I) was performed by Cu 1+ assisted nucleophilic exchange on 2‐Br‐T with a mean labelling yield of 85%. RPHPLC coupled to C18 Sep‐pak recovery allowed to obtain the radioactive compound with a radiochemical purity of >98%. The in vitro evaluation was carried out on WiDr cells (human colon carcinoma). L‐2‐ 125 I‐ tyrosine (2‐*I‐T) was shown to follow for the larger part the L‐transport system. For times up to 60 minutes the uptake was comparable with that of the reference 3 H‐tyr. A considerable amount of the radioactivity uptake was slowly washed out in efflux conditions. In comparison with 3 H‐tyr the incorporation in proteins was low. This can point to a retention mechanism which can be favourable for diagnosis. In vivo in rats bearing R1M rabdomyosarcoma tumours, the uptake in the tumour 40 minutes p.i. represented 1% ID/g with a tumour to blood ratio of 1.8. The tracer is fastly cleared from the blood to the bladder.