No abstract

99mTc-d,l-hexamethylpropylene amine oxime ((99m) Tc-d,l-HMPAO) is a widely used radiopharmaceutical that suffers from an inherent instability with a shelf life of 30 min that constrains its availability for clinical use. A protocol for improving the stability of the kit with minimal modification of manufacturer's instructions and no chemicals addition to the commercial formulation is proposed. The protocol is based on the displacement of the oxygen present in the preparation, preventing free radicals build up and free pertechnetate formation. Although the degradation of (99m) Tc-d,l-HMPAO cannot be explained solely by the radiolytic production of free radicals, it appears to be an important factor in the shelf stability of the complex.

To avoid adverse effects during the administration of [(123)I] meta-iodobenzylguanidine (MIBG), infusion of the drug that has been previously diluted is proposed. Stability of [(123)I] MIBG in sodium chloride solutions is studied, looking for incompatibilities in the formulation. Stability was tested on the basis of the percentage of free [(123)I] iodide on solid-phase extraction. No increase in percentages of free [(123)I] iodide was found in diluted and undiluted samples over time (P>0.05). Intravenous saline infusion of [(123)I] MIBG could be a useful tool for controlling the administration rate, minimizing the side effects and lowering the exposure of the staff to ionizing radiation.