Preparation and bulk production of 99mTc-sestamibi with new formulation

Full text: Technetium 99m-hexakis-2-methoxy-isobutyl-isonitril (Sestamibi or MIBI) was developed as a myocardial perfusion imaging agent. It was subsequently used as a tumour imaging agent for lung, mammary, thyroid, parathyroid and brain tumours and lymphoma because it accumulates in tumour 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. Regarding to climate in our country, sometimes we had some problems with current sestamibi kit formulation in nuclear medicine centers as low radiolabeling efficiency, so we try to introduce new formulation for this kit respect to our climate. In this new formulation, we changed some materials and decrease the amount of MIBI to half. After preparation of this formulation kit, as lyophilized, following quality control has been done: radiochemical purity, stability at room temperature, biodistribution in mice, determination of shelf life and sterility, pyrogenicity tests. Also, this kit has been sent to hospitals for clinical applications. Radiolabeling efficiency was more than 95 percent with up to 200 mCi of 99mTcO4-. This complex was stable at 6 hrs at room temperature. Biodistribution data in mice showed that 1.36 ± 0.11 percent of injected dose accumulated in heart after 30 min. The shelf life of lyophilized cold kit was more than one year. Clinical application had reasonable scan and during this period, there isn't any unfavorable reports. Our results showed that this kit is a suitable radiopharmaceutical for heart perfusion imaging. The study demonstrated that our formulation with half amount of MIBI regarding to current MIBI kit, has capacity for complexation of 200 mCi of pertechnetate, even one year after production of kit. (author)