Formulation of technetium 99-m succimer injection

Abstract

Three formulations of Ready-To-Use kit for preparation of Technetium Tc 99m Succimer Injections have been prepared in lyophilized form and packed in nitrogen atmosphere. The formulation 1 contained succimer and stannous chloride by the mole ratio of 3:1, pH 2.5. The formulation 2 and 3 have been prepared on the same basis except the ascorbic acid was added in the formulation 2 and both ascorbic acid and inositol were added in the formulation 3. The qualities of the formulations were evaluated at time 0, 1, 2 and 3 month(s) after preparations by labeling with 99mTc and analyzed for radiochemical purity using the procedures in USP XXII. The radiochemical purities of the three formulations tested during three month period were within the USP standards. However, when comparing the biodistribution of the preparation in rats between the freshly prepared formulations and the three month old formulations, there was significant difference in kidney distribution of formulation 1 (p < 0.05) but the difference was not found with the formulation 2 and 3. The ascorbic acid in the formulation 2 and 3 can stabilize the formulations, which should be because of the antioxidant property. The amount of ascorbic acid ranges from 0.018% to 0.28% has been proved to be effective for stabilizing the formulations. Furthermore, it was found that the labeled Technetium Tc 99m Succimer products from the formulation 2 and 3 were stable within 180 minutes. The change occurred with formulation 2 during 180 minutes to 24 hours duration was greater than that occurred with formulation 3. Thus, besides the use of inositol as bulking agent for lyophilization in the formulation 3, it can protect the labeled products from the decomposition accelerated by the radioactivity. The formulation 3 is suitable for use as a succimer cold kit for preparation of 99mTc labeled succimer for renal scanning agent. The labeled preparation can be used up to 180 minutes in case the radioactive concentration is high enough. Thus, the Ready-To-Use kit for preparation of Technetium Yc 99m Succimer Injection according to the formulation 3 can be simply prepared. The product has good quality and stability. However, the efficiency of the equipment such as lyophilizer might affect the properties of the product.