In house development of 99mTc-Rhenium sulfide colloidal nanoparticles for sentinel lymph node detection

In this study, rhenium sulfide colloidal nanoparticles were developed as radiopharmaceutical for sentinel lymph node detection. We directly used rhenium sulfide as a starting material for the preparation of colloidal nanoparticles. UV-visible spectrophotometry was used for characterization of in house developed colloidal particles. The size distribution of radioactive particles was studied by using membrane filtration method. The percentage of radiolabeled colloidal nanoparticles was determined by paper chromatography (PC). The study also includes in vitro stability, protein binding in human blood and bioevaluation in a rabbit model. The results indicate that 77.27 ± 3.26 % particles of size less than 20nm (suitable for lymphoscintigraphy) were radiolabeled. 99mTc labeled rhenium sulfide labeling efficacy with the radiometal is 98.5 ± 0.5%, which remains considerably stable beyond 5h at room temperature. Furthermore, it was observed that 70.2 ± 1.3 % radiolabeled colloid complex showed binding with the blood protein. Bioevaluation results show the remarkable achievement of our radiopharmaceutical. The in house prepared 99mTc labeled rhenium sulfide colloidal nanoparticles reached the sentinel node within 15 min of post injection. These results indicate that 99mTc labeled rhenium sulfide colloid nanoparticles kit produced by a novel procedure seems of significant potential as a feasible candidate for further development to be used in clinical practice.