Polyurethanes are polymers in which unit molecules are connected with urethane bonds due to the reaction of di-isocyanates and polyols. By proper choice of the variants of the components, and their ratio, optimal physical, chemical and biocompatibility characteristics are achieved.

Terumo selected highly biocompatible segmented polyurethane for the production of leukocyte removal filters: IMUGARD III and IMUFLEX systems.

Investigation of the mechanism of leukocyte removal with polyurethane shows that leukocytes are mostly mechanically trapped in small pores or dimples of the material. Very limited cell-material interaction and absence of cellular or protein activation result in the blood products of superior purity.

These unique characteristics allow Terumo to increase the number of application fields and to offer a large range of leukocyte removal systems.