Erik de Blois, Ho Sze Chan, Mark Konijnenberg, Rory de Zanger and Wouter A.P. Breeman Pages 2677 - 2685 ( 9 )
An overview how to measure and to quantify radiolysis by the addition of quenchers and to maintain Radio- Chemical Purity (RCP) of vulnerable methionine-containing regulatory peptides is presented. High RCP was only achieved with a combination of quenchers. However, quantification of RCP is not standardized, and therefore comparison of radiolabelling and RCP of regulatory peptides between different HPLC-systems and between laboratories is cumbersome. Therefore we suggest a set of standardized requirements to quantify RCP by HPLC for radiolabelled DTPA- or DOTA-peptides. Moreover, a dosimetry model was developed to calculate the doses in the reaction vials during radiolabelling and storage of the radiopeptides, and to predict RCP in the presence and absence of quenchers. RCP was measured by HPLC, and a relation between radiation dose and radiolysis of RCP was established. The here described quenchers are tested individually as ƒ(concentration) to investigate efficacy to reduce radiolysis of radiolabelled methionine-containing regulatory peptides.
gastrin releasing peptide, HPLC, minigastrin, quenchers, radiochemical purity, radiolysis, methionine, regulatory peptides
Erasmus MC Rotterdam, Department of Nuclear Medicine, ‘s Gravendijkwal 230, 3015 CE Rotterdam, The Netherlands.