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99m Tc‐branched‐chain‐polypeptide (BCP): a potential synthetic radiopharmaceutical
Author(s) -
Perkins Alan C.,
Frier Malcolm,
Pimm Malcolm V.,
Hudecz Ferenc
Publication year - 1998
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/(sici)1099-1344(199807)41:7<631::aid-jlcr109>3.0.co;2-0
Subject(s) - chemistry , chain (unit) , stereochemistry , combinatorial chemistry , radiochemistry , physics , astronomy
Synthetic polymers and polypeptides are currently being investigated as a basis for a new generation of radiopharmaceuticals which do not rely on the availability of human blood products of animal derived proteins. In the present study a polyanionic branched chain polypeptide (BCP) based on a poly(L‐lysine) backbone with DL‐Ala oligomer side chains (three residues on average) terminating in acetylated glutamic acid (AcEAK) was conjugated to DTPA by reaction with DTPA anhydride prior to electrolytic radiolabelling with 99m Tc. The radiolabelling efficiency of incorporation of 99m Tc was between 40 and 50%. The radiochemical purity on ITLC with butanone was >90%. 10MBq 99m Tc‐AcEAK were administered intravenously to normal Wistar rats and the in vivo biodistribution assessed by imaging with a gamma camera. Imaging demonstrated the distribution of 99m Tc‐AcEAK throughout the body with greatest concentration of activity in the vascular organs such as the heart and liver. Quantification from the images demonstrated 65% of the whole body activity remained at 4 hours. Focal increased uptake was also visualised in the left ear of one rat which was subsequently found to be a site of infection. This study demonstrates that 99m Tc‐BCP offers potential for use as a radiopharmaceutical for blood pool and possibly infection imaging. © 1998 John Wiley & Sons, Ltd.