NUCLEAR PHARMACY Rapid Quality Control of Technetium-99m-2-Methoxy Isobutyl Isonitrile (Technetium-99m-Sestamibi)

Objective: Technetium-99m-sestamibi (-1"'Tc-MIBI) is a radiopharmaceutical imaging agent useful for assessing myocardial perfusion. We present a simple, rapid and accurate SepPak® method to confirm the radiochemical purity of "'Tc-MIBI. Methods: Technetium-99m-MIBI preparations of high (>95%), intermediate (83-90%) and low (25-43%) radiochemical purity were evaluated by the recommended thinlayer chromatography (TLC) procedure. Radiochemical purities were simultaneously determined by Alumina-N and C-18 SepPak treatment using 95% ethanol and 0.9% sodium chloride injection, USP as eluents. Statistical analysis was used to determine concordance between TLC and corresponding SepPak values for the entire range of "'TcMIBI purity studied. Results: For all purity groups studied, a significant difference was found when "'Tc-MIBI radiochemical purity values by the C-18 SepPak method were compared to values obtained by the recommended TLC procedure. However, no statistical difference in "'Tc-MIBI radiochemical purity values were found when Alumina-N SepPaks, treated with sufficient eluent, were compared to values obtained by the recommended TLC procedure. Conclusion: This study demonstrates that an Alumina-N SepPak method can be routinely used as an alternative to the recommended TLC method for the radiochemical purity determination of "'Tc-MIBI.