Evaluation of a vial adaptor to ensure safe and efficient needle-free transfer of cells post-cryopreservation in preparation for drug delivery

Abstract

Background & Aim The commercialization of cells for therapeutic use drives a critical need for the refinement of cell storage and handling procedures, ensuring the integrity of cell-based products is maintained throughout the product life cycle. One area for refinement is the transfer of cells from a sealed container system after they have been cryopreserved, stored, shipped and thawed. There are many parameters that may affect either the total volume or the viability of the cells recovered. These include the type of transfer equipment used, the properties of the cryo-formulations that may have different viscosities or rheology, and the proficiency of the manual operator performing the task. This study investigates the comparability of a vial adaptor when compared to a traditional needle and syringe for recovering cells from a sealed cyclic olefin polymer (COP) vials after cryopreservation and storage for one week at -180°C. Methods, Results & Conclusion One experiment was designed to evaluate the effect of operator variability (n = 4) when transferring 1 ml fill volumes containing 1 × 106 cells/ml stored in Cryostor CS10 using a vial adaptor or needle and syringe. Bone marrow-derived human mesenchymal stem cells (hMSCs) and cord blood hematopoietic stem cells (HSCs) were used as exemplar adherent and suspension cell types. Total volume recovery from each system was measured, as was morphology, cell yield and viability after a 4-day outgrowth to determine cell and volume losses from the transfer process. A second experiment looked at the effect different cell densities and cryo-formulations may have during transfer. 1ml vials of hMSCs at different densities (5 e5/ml and 4 e6/ml) were prepared and stored in 4 different formulations with differing colloidal components. The cell yield and viability were measured immediately post-transfer as was total recovered volume. The results showed that recovery of both intact cells and product volume were >80% for recovered volume with a suitable cryo-formulation regardless of transfer method (Figure 1). The vial adaptor was comparable in performance to a needle and syringe, thus providing a safe needle-free alternative for operators during manual transfer. Furthermore, the data highlighted the how cryo-formulation choice and operator variability can impact upon overall product recovery in a cell therapy context.