Myocardial imaging agent [Tc-99m-2-methoxy isobuty sonitrile [MIBI]] synthesis, myocardial uptake, biodistribution in the animal and human models [a preliminary report]

ABSTRACT

2-methoxy isobutyl isonitrile [MIBI] was synthesized following Subramanian procedure and formulated into 'instant kits'. The quality control of the kits showed 97.5% radio chemical purity and 98% stability at 6 hr, with shelf half life of more than 6 months. In the animal model, blood activity [TC-99m MIBI] gradually decreased from 21.4% at 5 mins to 2.1 +/- 1% at 60 min. The organ distribution at 60 min showed, liver 70 +/- 5%, heart 21 +/- 6%, kidney 52 +/- 2% and lungs 33.4 +/- 6%. The heart to organ ratio was heart/liver 0.3, heart/lung 0.6, heart/spleen 0.36 and heart/kidney 0.4. On human model, blood activity of injected dose [[ID], 29.2 +/- 3% at 30 sec and 2.1 +/- 1% at 60 min. The organ activity at 60 min, liver 62 +/- 3%, heart 24 +/- 4%, spleen 57 +/- 3% and lung 44.5 +/- 6%. The heart to organ ratio, heart/liver 1.3 +/- 0.2, heart/lung 2.1 +/- 0.3 and heart/spleen 2.6 +/- 0.8. The study provided first reported evaluation of Tc-99m MIBI in experimental and clinical trials in Pakistan. The results confirmed that the distribution of the MIBI remained relatively fixed in experimental studies, no significant redistribution accrued. Moreover, the images obtained are of high technical quality