Comparison of hplc, tlc and minicolumn for measuring the radiochemical purity of ⁹⁹tc^m-q12

TechneScan Q12® (⁹⁹Tc(m)-Q12) is a new agent for clinical myocardial perfusion imaging. A product with high radiochemical purity is essential for high-quality imaging. We compared three methods of radiochemical purity analysis for ⁹⁹Tc(m)-Q12: thin-layer chromatography (TLC), high-performance liquid chromatography (HPLC) and minicolumn. Thin-layer chromatography resulted in lower purity (87 ± 8%) than the minicolumn method (aluminium oxide minicolumn, ethanol) (95 ± 4%). The HPLC method resulted in the lowest purity (79 ± 11%). The main impurity was a polar compound, but three further impurities were found using HPLC. Using HPLC, we found the percentage of the parent compound (⁹⁹Tc(m)-Q12) in plasma at 40-90 min post-injection to be 19.3 ± 6.2%. We suggest that gradient HPLC is the most effective method for the analysis of the radiochemical purity of ⁹⁹Tc(m)-Q12, and that it can be used to determine the concentration of ⁹⁹Tc(m)-Q12 in plasma.