Searching for Alternative Plasticizers for Red Blood Cell Storage Bags

October 15, 2015

debchenBy Deb Chen, PhD Candidate in Devine Lab, CBR

Image by Deb Chen

Polyvinyl chloride, commonly abbreviated as PVC, is a plastic polymer widely used in medical device production. However, PVC is brittle at room temperature and a plasticizer, or “softener”, is typically added to increase its flexibility. Currently, DEHP (di-(2-ethylhexyl) phthalate) is the “softener” used in blood bag production to provide the necessary durability and flexibility, as an example for red blood cell (RBC) storage.

However, DEHP is known to leach out of the plastic blood bag into the RBC suspension and exposures to high levels of DEHP have been shown to cause reproductive and developmental harm in laboratory animals. Although no adverse events in humans are reported to date, precautions are taken to minimize the exposure to DEHP, especially for vulnerable populations such as newborns, infants, and pregnant women.

Despite DEHP being deemed safe by the American Council on Science and Health, the Health Canada Expert Advisory panel on DEHP in Medical Devices encouraged research efforts to identify alternatives to this chemical.

A collaboration between Fresenius-Kabi, a manufacturing company of blood storage bags, and the CBR team lead by Dr. Dana Devine aimed to evaluate the comparative quality of RBC stored in pediatric bags manufactured using two alternative plasticizers to DEHP: di-isononyl cyclohexane-1,2-dicarboxylic acid (DINCH) and butyryl-n-trihexyl-citrate (citrate). The results of this evaluation are published in Vox Sanguinis, 2015.

This comparative study suggests that the current DEHP plasticizer is best at preserving RBC quality, and DINCH, an alternative plasticizer may also be feasible for blood storage bag production. Citrate, on the other hand, appeared to be detrimental for RBC storage, as blood stored in citrate bags failed to meet the regulatory guidelines set by the Canadian Standards Association. While further effort into finding a feasible alternative continues, DEHP appears to be the best blood storage bag plasticizer to date.

Serrano K, Levin E, Chen D, Hansen A, Turner TR, Kurach J, Reidel A, Boecker W, Acker JP, and Devine DV. An investigation of red blood cell concentrate quality during storage in paediatric-sized polyvinylchloride bags plasticized with alternatives to di-2-ethylhexyl phthalate (DEHP). Vox Sang. 2015.