The kit includes a lyophilized mixture of a copper complex of MIBI (tetrakis(2-methoxyisobutylisonitrile)copper(I) tetrafluoroborate ([Cu(MIBI)4]BF4)) as the active ingredient, sodium citrate dihydrate as a buffer, L-cysteine hydrochloride monohydrate as a stabilization aid, mannitol as a lyophilization aid, and stannous chloride dihydrate as a reducing agent. Prior to use, the lyophilized mixture is reconstituted with sodium pertechnetate (99mTc) and boiled to form technetium (99mTc) Sestamibi. The U.S. Pharmacopoeia (29th Ed.) requires that a mean of not less than 90% (corrected area percentage) of the total radioactivity is represented by 99mTc-Sestamibi, and a mean of not more than 5% (corrected area percentage) of the total radioactivity is present as 99mTc pentamibi dimethylvinyl isonitrile.
