Formulation and quality control of single dose 99mTc-sestamibi as a myocardial perfusion imaging agent

Introduction: 99mTc-sestamibi is a cationic 99mTc complex which has been found to accumulate in viable myocardial tissue in a manner analogous to that of thallous chloride Tl-201.Scintigraphic images obtained in humans after the intravenous administration of the drug have been comparable to those obtained with thallous chloride Tl-201 in normal and abnormal myocardial tissue.It was subsequently used as a tumor imaging agent for lung, mammary, thyroid, parathyroid, brain tumors and lymphoma because it accumulates in tumor cells. 99mTc-sestamibi is a number of a chemical family referred to as isonitril. This radiopharmaceutical is a monovalent cation in which 99mTc is surrounded by six isonitril ligands. Methods: In this new formulation, we changed the formulation of multi-dose MIBI kit to single dose for one patient and then we reduced the amount of the main ligand (MIBI). After getting a new formulation, the MIBI-SD produced as lyophilized, following quality control has been done: radiochemical purity, stability at room temperature, biodistribution in mice, determination of shelf life and sterility, pyrogenicity test. Results: Radiolabelling efficiency was more than 95 percent with up to 30.0 mCi of pertechnetate (99mTcO4-). The 99mTc-MIBI-SD complex was stable at 6 hrs at room temperature. Biodistribution in mice showed that the percent of injected dose accumulation in heart after 30.0 min was the same amount of MIBI multi-dose kit. Conclusion: The study demonstrates that our formulation of 99mTc-MIBI-SD as a 99mTc-radiopharmaceutical for myocardial imaging agent is stable after one year of shelf-life. Besides, we sent it to the nuclear medicine centers for clinical evaluation.