Synthesis and characterization of a noncytotoxic, X-ray opaque polyurethane containing iodinated hydroquinone bis(2-hydroxyethyl) ether as chain extender for biomedical applications.

An iodinated urethane polymer that does not require addition of X-ray attenuating additives to impart X-ray opacity was synthesized and characterized for biomedical applications. A new X-ray opaque diiodo compound, namely, 2,2'-(2,5-diiodobenzene-1,4-diyl)bis(oxy)diethanol (DBD), was synthesized by iodinating hydroquinone bis(2-hydroxyethyl) ether and this compound was used as chain extender during polyurethane synthesis so that X-ray opacity could be imparted to the polymer formed. X-ray opaque polyurethane (XPU) was synthesized by reacting 1,6-diisocyanatohexane with poly(hexamethylene carbonate)diol and DBD. X-ray opacity of XPU was measured with a fluoroscopy machine using BaSO4 -filled polyurethane as controls. Radiographic images showed that XPU sample had X-ray opacity equivalent to 15 wt % BaSO4-filled polymer. In vivo imaging in a rabbit model showed that the material could be readily distinguishable from bones. XPU was found to be hemocompatible and noncytotoxic to L929 fibroblast cell lines. Optical transparency measurements using ultraviolet-visible spectrophotometer showed that XPU transmitted 85% of visible light.