Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – From reactant having at least one -n=c=x group as well as...
Patent
1992-12-11
1994-06-07
Welsh, Maurice J.
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
From reactant having at least one -n=c=x group as well as...
528 745, 528 76, 528 80, 528 83, 528 85, C08L 7504
Patent
active
053190599
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a plastic material which is opaque to X-rays, in particular, polyurethane having a covalently linked X-ray contrast material.
2. Description of the Prior Art
Use of plastics in industry, agriculture, medicine or other applications is often tied to the question of locating and testing the material during its use. In addition in medical applications it must not only be possible to locate the implanted or applied plastics, but also the plastics must be removable from the human or animal body after a set period of time. As a rule, removal requires a further surgical procedure. Although easily locatable plastics are known, they are chemically stable and can only be removed from the human body by a surgical procedure. On the other hand, plastics are known which degrade and are removed from the body after a certain time when their purpose has been served. However, such plastics are not easy to locate.
A polyurethane which is opaque to X-rays but which is not has been disclosed biologically degradable in Derwent Abstract 87-348546/49 of WO 8707-155 which, however, is not biologically degradable. However if it were biologically degradable, highly toxic halogen derivates of isophtalic acid would be created, as a result of which the polymer would not be biocompatible. Biocompatible and/or biodegradable polyurethanes which, however, are not X-ray contrasting, have been disclosed in J. Polym. Sci., Polym. Symp. 66, pp. 259 to 268 (1979) or J. Polym. Sci., Polym. Symp. 66, pp. 239 to 257 (1979), as well as in Houben-Weyl, Methoden der organischen Chemie [Methods of Organic Chemistry], Volume E 20, Makromol. Stoffe [Macromolecular Materials], pp. 1719 to 1721 (1987).
SUMMARY OF THE INVENTION
Accordingly, it is an object of this invention to provide a material which, can be located with a high degree of accuracy and which can also be dissolved in the human or animal body.
This object is attained by a material of polyurethane with a covalently linked X-ray contrast material in accordance with one embodiment of this invention comprising a polyurethane which is biocompatible, stable or biodegradable in an appropriate environment, and X-ray contrasting.
DESCRIPTION OF PREFERRED EMBODIMENTS
Polyurethanes impervious to X-rays are particularly suited for temporary or permanent use of in connection with X-ray identification. In the solid aggregate state, devices, structures, films, foils, tubes, hoses, screws, rods or other three-dimensional compact or hollow structures are made from polyurethanes in addition the polyurethane in case is also suitable for coatings of the structures, insulation, seals and as a drug carrier. In the liquid aggregate state, the polyurethane can be used for filling empty or filled biological or technical hollow spaces and/or for diagnostic, medical or technical purposes. Furthermore, the polyurethane can be used for the additional purpose of X-ray identification. The polyurethane can also be employed in the form of sprays, dispersions or as a dispersion medium. Work pieces can be coated with this polyurethane, but topical application is also not excluded. Hardening by application of external energy is used for this application.
For example blockage of the exocrinal duct system of the pancreas by injection of the dissolved plastic through a catheter is a surgical procedure which may be required during transplantation of this organ.
From a medical viewpoint, the plastic to be used for this purpose requires specific properties, including:
a. Biocompatibility
b. Solubility in solvents which are only weakly or not toxic, such as alcohol, dimethylsulfoxide, DIM or their mixtures,
c. Insolubility in an aqueous environment (water, blood, etc.)
d. Solid, resilient or visco-resilient behavior following precipitation,
e. Ability to decompose biologically, and
f. X-ray absorbency to a sufficient and variable extent.
In particular, polyurethanes are suitable in which one of their two basic compounds, in this case the diol compoun
REFERENCES:
patent: 3852341 (1974-12-01), Bjork et al.
patent: 4283447 (1981-08-01), Flynn
patent: 4406878 (1983-09-01), DeBoer
Lipatova, T. E., "Some Chemical Aspects of the Behavior of Synthetic Polymers in a Living Organism", Journal of Polymer Science: Polymer Symposium 66, pp. 239-257 (1979).
Masar, B., et al., "Synthesis of Polyurethanes and Investigation of their Hydrolytic Stability", Journal of Polymer Science: Polymer Symposium 66, 259-268 (1979), John Wiley & Sons, Inc.
Houben-Weyl, Methoden der organischen Chemie (Methods of Organic Chemistry), vol. E 20, Makromol. Stoffe (Macromolecular Materials), pp. 1719 to 1721 (1987).
Neuenschwander Peter
Redha Falah
Suter Ulrich W.
Uhlschmid Georg
Jeck Juliane
Welsh Maurice J.
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