Routine determination of radiochemical purity of 99mTc-MIBI.

The manufacturer recommends that the radiochemical purity of 99mTc-MIBI be determined with alumina TLC plates developed in ethanol, but for routine use this is slow and requires care. After comparing a variety of systems, we obtained equivalent results using ITLC-SG strips developed with saline to determine [99mTc]pertechnetate and with acetone to determine 99mTc colloid; % 99mTc-MIBI was determined by difference from 100%. These separations are the opposite of those obtained with the routine polar 99mTc radiopharmaceuticals. Equivalent results were obtained even more rapidly by extracting 99mTc-MIBI from water into chloroform.