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Development of kit formulations for 99m TcN‐MPO: a cationic radiotracer for myocardial perfusion imaging
Author(s) -
Zheng Yumin,
Ji Shundong,
Tomaselli Elena,
Liu Shuang
Publication year - 2014
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.3221
Subject(s) - vial , chemistry , biodistribution , radiochemistry , myeloperoxidase , nuclear chemistry , nuclear medicine , chromatography , in vitro , biochemistry , medicine , inflammation
The objective of this study was to develop a kit formulation for [ 99m TcN(mpo)(PNP5)] + (MPO = 2‐mercaptopyridine oxide), ( 99m TcN‐MPO) to support its clinical evaluations as a SPECT radiotracer. Radiolabeling studies were performed using three different formulations (two‐vial formulation and single‐vial formulations with/without SnCl 2 ) to explore the factors influencing radiochemical purity (RCP) of 99m TcN‐MPO. We found that the most important factor affecting the RCP of 99m TcN‐MPO was the purity of PNP5. 99m TcN‐MPO was prepared >98% RCP ( n = 20) using the two‐vial formulation. For single‐vial formulations with/without SnCl 2 , β ‐cyclodextrin ( β ‐CD) is particularly useful as a stabilizer for PNP5. The RCP of 99m TcN‐MPO was 95–98% using β ‐CD, but its RCP was only 90–93% with γ ‐cyclodextrin ( γ ‐CD). It seems that PNP5 fits better into the inner cavity of β ‐CD, which forms more stable inclusion complex than γ ‐CD in the single‐vial formulations. The results from biodistribution and imaging studies in Sprague–Dawley rats clearly demonstrated biological equivalence of three different formulations. Single photon‐emission computed tomography data suggested that high quality images could be obtained at 0–30‐min post‐injection without significant interference from the liver radioactivity. Considering the ease for 99m Tc‐labeling and high RCP of 99m TcN‐MPO, the non‐SnCl 2 single‐vial formulation is an attractive choice for future clinical studies.