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
1999-03-12
2000-11-21
Gorr, Rachel
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 72, 528 73, 524718, 424 7808, 424 783, C08G 1830
Patent
active
061504890
DESCRIPTION:
BRIEF SUMMARY
This invention relates to thermoplastic polyurethanes (TPUs) which contain pharmaceutical active ingredients in a homogeneous distribution, to a method of producing them, and to their use in medical articles. During the production of the TPUs, compounds having an antithrombotic or antibacterial effect are added to the monomer mixture.
In addition to suitable mechanical properties and good biocompatibility or good compatibility with blood, Materials which are used in medicine and which come into direct contact with blood, e.g. artificial organs, artificial blood vessels, catheters, blood transfusion devices, also have to exhibit an antithrombotic and/or antibacterial effect.
Polymer materials are known for medical applications which comprise coatings which contain heparin or another substance having an antithrombotic effect. However, since only small amounts of active ingredient can be incorporated in the applied coating, a sufficiently high concentration of the active ingredient is not available on the surface of the medical article over the entire duration of use thereof.
Methods of incorporating substances having an antithrombotic effect in the outer polymer layer of medical articles are also known. According to EP-A 550 875, medical articles made of polymeric material are pretreated with a solvent so that a pharmaceutically active layer can penetrate the polymer. This method is costly on an industrial scale and employs organic solvents which for the most part cannot be removed from the material without leaving a residue. Moreover, only a low surface concentration of the substance is obtained.
The antithrombotic effect of acetylsalicylic acid is known (Munchner Medizinische Wochenschrift 130 (1988) 809). According to DE-C 42 21 665, esters or mixed esters of acetylsalicylic acid are added to polymers as additives in order to suppress the clotting of blood. However, it has proved to be a disadvantage in that only special derivatives of acetylsalicylic acid can be used, and the surfaces do not achieve their optimum biocompatibility until some time has elapsed, since the active ingredient first has to migrate to the surface of the polymer.
According EP-A 659 442, a mixture of amide wax and acetylic acid ethylenediamine is added to the granulated polymer material, to speed up this process of migration, before thermoplastic processing is effected. The amide wax melts during processing and, due to its incompatibility with the polymer, migrates to the surface of the finished part. The migration of the acetylsalicylic acid derivative is thereby assisted. However, only limited amounts of active ingredient can be added to the granular material and can thereby be incorporated in the medical article. Moreover, a special derivative of acetylsalicylic acid is also required for this method.
A common feature of all the aforementioned methods is that providing articles for medical use with a pharmacologically active substance necessitates an additional operation, namely either the pretreatment of the polymer material before processing or subsequent treatment of the mouldings produced. This gives rise to additional costs and is accompanied by an increase in the time which is required for production. It has now been found that, for the production of articles for medical use from thermoplastic polyurethanes, active ingredients can be added even during the production of the polymer. The polymer which is obtained can be further processed, in a conventional manner and without additional cost, to produce articles for medical use which contain active ingredients.
The present invention therefore relates to a method of producing thermoplastically processable polyurethanes which contain active ingredients by the reaction of the polyurethane-forming components 10,000, materials, of a pharmacologically active substance, which are reactive towards isocyanate is 0.9 to 1.2.
Examples of organic diisocyanates A) include aliphatic, cycloaliphatic, araliphatic, heterocyclic and aromatic diisocyanates such as those which are described in Ju
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Munchner Medizinische Wachenschrift, 130 (Month unavailable) 1988, pp. 809-814, K. Schror, "Azetylsalizylsaure--von Antirheumatikum zum Antithrombotikum".
Justus Liebings Annanlen der Chemie, 562, pp. 75-136, Dec. 11, 1948, Von Werner Siefken, "Mono- und Polyisocyanate, IV. Mitteilung uber Polyurethane".
Dujardin Ralf
Hobler Hartwin
Pudleiner Heinz
Bayer Aktiengesellschaft
Gil Joseph C.
Gorr Rachel
Preis Aron
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