Influence of Storage Temperature on Radiochemical Purity of 99mTc-Radiopharmaceuticals

Abstract

The influence of effective room temperature on the radiochemical purity of 99mTc-radiopharmaceuticals was reported. This study was born from the observation that in the isolators used for the preparation of the 99mTc-radiopharmaceuticals the temperatures can be higher than those reported in the commercial illustrative leaflets of the kits. This is due, in particular, to the small size of the work area, the presence of instruments for heating, the continuous activation of air filtration, in addition to the fact that the environment of the isolator used for the 99mTc-radiopharmaceuticals preparation and storage is completely isolated and not conditioned. A total of 244 99mTc-radiopharmaceutical preparations (seven different types) have been tested and the radiochemical purity was checked at the end of preparation and until the expiry time. Moreover, we found that the mean temperature into the isolator was significantly higher than 25 °C, the temperature, in general, required for the preparation and storage of 99mTc-radiopharmaceuticals. Results confirmed the radiochemical stability of radiopharmaceutical products. However, as required in the field of quality assurance, the impact that different conditions than those required by the manufacturer on the radiopharmaceuticals quality have to be verified before human administration.

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“…For these reasons, there might be an interest to consolidate this business and even to further optimize the existing products, which are often characterized by a short expiration data for lyophilized kits and the limited shelf life (hours) of the radiopharmaceutical after reconstitution. The latter is due not only to the intrinsic 99m Tc-decay but also to the molecular overall stability, which is hardly affected by the radioactivity present in the prepared injectable solution …”

“…The latter is due not only to the intrinsic 99m Tc-decay but also to the molecular overall stability, which is hardly affected by the radioactivity present in the prepared injectable solution. 54 A total of 19 analyzed patents disclosed inventions using authorized radiopharmaceuticals but with substantial differences in the indication of use or in the composition.…”

Interdisciplinary Tasks in the Cyclotron Production of Radiometals for Medical Applications. The Case of 47Sc as Example

“…The SE of metals by an organic solvent, such as in the case of 99m Tc, is often followed by further purification step of the product from the solvent, by means of column chromatography [55,56,57,58]. This method allows to obtain [ 99m Tc]TcO 4 - with high chemical and radiochemical purity suitable for the following radiolabeling procedure, particularly sensitive to the quality of 99m Tc-pertechnetate solution [13,59,60].…”

LARAMED: A Laboratory for Radioisotopes of Medical Interest

“…Outcomes from those experiments has triggered a research interest on 99m Tc-radiopharmaceuticals involving part of the group in the development of new tracers and the evaluation of 99m Tc routine practice [27,28,29,30].…”