Progress in the removal of di-[2-ethylhexyl]-phthalate as plasticizer in blood bags

Polyvinylchloride (PVC) is used in blood component containers as well as in many other medical devices because it shows optimal inertness, durability, and resistance to heat and chemicals. However, the polymer itself does not provide good handling characteristics or the necessary properties for red blood cell (RBC) survival. PVC thus needs to be plasticized, and di-(2-ethylhexyl)phthalate (DEHP) has been the most common plasticizer to produce the required flexibility to PVC. However, DEHP has been found to leach out from the containers, causing toxic effects, as demonstrated mainly in rodents. It is considered to be a possible carcinogen and suspected to also produce endocrine effects especially in young males. Although controversial, it is commonly accepted that in vulnerable patients such as newborns, trauma patients, or pregnant women, high exposure to DEHP should be avoided. The replacement of the common PVC + DEHP blood bags poses technical challenges due to the positive influence of the DEHP molecules on the red blood cell (RBC) membrane, and thus it has been shown to affect RBC storage and survival after transfusion. Different approaches are thus being taken to find a suitable alternative to DEHP for blood components bags. Environmentalists even favor the substitution of the PVC to avoid not only the plasticizers but even the other residues contained in the polymer material. Consequently, whereas the simplest solution is the substitution of the DEHP by other plasticizers, alternative plasticizer-free materials are becoming explored. Even modifications of existing materials are being presented by some research groups, ranging from covering of the DEHP-containing materials to alloys or special additive solutions. Different strategies as well as the most promising approaches are presented in this review. In any case, the degree of stabilization of RBCs undergoing prolonged storage will dictate the final acceptance for such alternatives.