Evaluating product stability and the potential for blood and radioactive contamination when using a closed system adaptor for the preparation of radio labeled red blood cells.

Objectives: To determine the impact of a closed system adaptor when preparing a commercially available red blood cell labeling kit. Variables evaluated included product stability as well as the potential for both blood and radioactive contamination.

Methods: Test samples of a commercially available kit for the radiolabeling of red blood cells using an invitro labeling method were prepared using the closed system adaptor, consisting of a single puncture vial adaptor which was placed after swabbing the septum of the kit. Kits were radiolabeled using package insert procedures, but all syringe additions were performed using a syringe adaptor which directly interfaces with the vial adaptor being used, creating a needleless transfer system. Three (3) kits were radiolabeled using several labeling scenarios: a) 3 ml of “fresh” Tc-99m sodium pertechnetate, 3 ml of human blood with heparin as anticoagulant, b) 3 ml of “fresh” Tc-99m sodium pertechnetate, 3 ml of human blood with sodium citrate as anticoagulant, c) 3 ml of “12 hour” Tc-99m sodium pertechnetate, 3 ml of human blood with heparin as anticoagulant, d) 3 ml of “12 hour” Tc-99m sodium pertechnetate, 3 ml of human blood with sodium citrate as anticoagulant. Three (3) additional vials were prepared for each scenario as control samples using package insert procedures without the closed system adaptor and using needle based transfers. While the kits were radiolabeling, cotton tipped swabs were used to wipe the vials and the closed system adaptors and evaluated for both presence of blood contamination as well as for the presence of radioactive contamination by counting the swabs in a single channel analyzer. Further examination of the work area was performed by spraying the area with a chemiluminescent agent and evaluating for blood spatter as well as surveying for the presence of radioactive contamination using a Geiger-Mueller survey meter. At the completion of the radiolabeling step, 0.2 ml of the final product was added to a centrifuge tube containing 2ml of normal saline, centrifuged and the activity in the residual button and plasma was evaluated to determine radiolabeling efficiency of the final product. Additional samples were obtained 30 and 60 minutes post radiolabeling to evaluate for product breakdown. Data from the closed system adaptor vials was compared to the controls to determine the effect of the closed system adaptor in each of the areas of comparison.

Results: Preliminary results show that the closed system adaptor has minimal effects on the radiolabeling efficiency of the kit formulation, while minimizing both radioactive and blood contamination that occurs in the labeling process.

Conclusion: The closed system adaptor has the potential for providing an additional layer of safety for users who radiolabel red blood cells using the commercially available kit formulation without significant impact on the quality of the final product. Research Support: This project was supported by a grant from Teva Pharmaceuticals