Background
Most polymeric materials are not natively radio opaque, requiring additives to make them so. Recently, interest has increased in the development of radio-opaque polymers produced without additives. Additive-free, biocompatible polymers that are radio opaque could be used as implantable devices in the human body. Such use, however, comes with the challenge of monitoring these devices using standard X-ray imaging techniques. Most suitable polymers, however, do not absorb significantly in the X-ray region of the electromagnetic spectrum.

Polymeric materials such as metal-containing ceramic-polymer blends and hydrogels that include iodine are opaque to X-rays. However, these materials either are not biocompatible or lack physical properties that enable the widespread use of these materials in medical applications such as implants.

A need therefore exists for new polymeric materials that are radio opaque and which are suitable for inclusion within implants for use in the human body.

Invention Description
This disclosure details the synthesis of a polyphosphazene polymers containing 4-iodophenoxy, 4-iodophenyl alanine ethyl ester, or 3,5-diiodo tyrosine ethyl ester side groups. These polymers can be formed into films through solution casting or thermal processing methods. These films were radio opaque when imaged using medical X-ray equipment and show a high potential for lightweight biostable and bioerodable materials. Bioerodible polymers will degrade under ambient biological conditions into biologically benign products.

File Number: 3542