Radiolabelling of RC-160, a Promising Somatostatin Analogue for Cancer Diagnosis

Alice Lázníčková¹ (laznicko@faf.cuni.cz), Mathew L. Thakur²

¹Charles University in Prague, Faculty of Pharmacy, Hradec Králové, Czech Republic
²Thomas Jefferson University Hospital, Philadelphia, USA

Summary

Labelling of RC-160, a somatostatin receptor specific octapeptide, with ^99mTc and ¹²⁵I was studied. For radiolabelling of RC-160 with ^99mTc the direct method based on reduction of disulphide groups of the peptide by ascorbate to sulfhydryls (strong binding groups for technetium) was used. For labelling of RC-160 with ¹²⁵I, either chloramine-T or iodogen methods were employed. Even if RC-160 can be directly labelled with both radionuclides, the purification of the product is necessary to achieve high radiochemical purity. The labelling procedures are difficult as they require special skills which are not available in every radiopharmacy unit, and they are also time consuming and therefore unsuitable for routine investigation.