 99m Tc-cAbVCAM1-5 is a new experimental radiotracer targeting a marker of inflammation found in vulnerable atheromatous plaques in cardiac diseases.  In order to complete an investigational medicinal product dossier, a validation of the analytical method New radiotracer requires validation of analytical method to assess radiochemical purity by HPLC and TLC is required.  Specificity, accuracy, repeatability and intermediate precision, linearity, robustness, quantification limit (LoQ), and range criteria were assessed for HPLC and TLC method.  The results developed in this study show that the analytical method is particularly suitable for assessing the radiochemical purity of 99m Tc-cAbVCAM1-5 in our laboratory.

Cardiovascular diseases, including fatal myocardial infarctions from atheromatous plaques, are the primary global mortality cause. Detecting stenotic atheromatous plaques is possible through coronary angiography, but vulnerable plaques with eccentric remodeling are undetectable with current diagnostic methods. Addressing this challenge, our group developed a radiopharmaceutical drug targeting Vvascular Ccell Aadhesion Mmolecule 1 (VCAM-1), radiolabeled with technetium-99m.

Given the absence of a monograph in the European Pharmacopoeia, and in order to draft the investigational medicinal product documentation, analytical methods had to be validated by Hhigh Pperformance Lliquid Cchromatography (HPLC) and Tthin Llayer Cchromatography (TLC) to determine the radiochemical purity (RCP) of 99m Tc-cAbVCAM1-5. This study therefore presents the results of the validation of analytical methods obtained in this context. The method validation followed the European Association of Nuclear Medicine (EANM) recommendations adapted from ICH Q2(R1), ensuring conformity with specificity, accuracy, repeatability and intermediate precision, linearity, robustness, quantification limit (LoQ), and range criteria. Regarding the results of specificity, both HPLC and TLC methods demonstrated excellent separation of 99m Tc-cAbVCAM1-5 from impurities 99m TcO4 -. Accuracy results indicated recovery percentages within the range of 99.52 to 101.40 % for the HPLC and 99.51 to 101.97 % for TLC, ensuring reliable measurements for each concentration of 99m TcO 4 -. Precision of the methods was validated by assessing repeatability and intermediate precision. Linearity was determined over the usual concentrations range and the correlation coefficient was greater than 0.99 for both methods. The limit of quantification was measured by diluting the 99m TcO 4

-to obtain a signal-to-noise ratio of around 10:1. Under these conditions, we obtained an LOQ of 2.10 MBq/mL for HPLC and 2Mbq/mL for TLC. In conclusion, the analytical methods developed in this study comply with EANM recommendations. This therefore allows us to correctly assess the radiochemical purity of 99m Tc-cAbVCAM1-5, a new radiotracer targeting inflammation in vulnerable plaques.