Absorbable iron-based alloy implantation medical appliance

Abstract

The invention relates to an absorbable iron-based alloy implantation medical appliance which includes an iron-based alloy base body, a degradable polymer formed on the surface of the iron-based alloy base body, and a corrosion inhibiting layer formed on the surface of the iron-based alloy base body. The corrosion inhibiting layer can delay corrosion on the iron-based alloy base body in early stage and ensures mechanical performances of the implanted medical appliance in early stage, and also can inhibit degradation of the polymer in the early stage of implantation of the medical appliance, thereby reducing usage amount of the degradable polymer and reducing risk of inflammation reaction.

Description

technical field [0001] The invention belongs to the field of absorbable implantable medical devices, in particular to an absorbable iron-based alloy implantable medical device. Background technique [0002] At present, bioabsorbable implantable medical device materials mainly include polymers, magnesium-based alloys, and iron-based alloys. Among the polymers, polylactic acid is the most widely used. Its advantage is that it can be completely degraded and absorbed, and the degradation products are carbon dioxide and water. Its disadvantage is that its mechanical properties are insufficient. Compared with metal-based devices, if the two are to meet the same mechanical properties, the size of polymer-based devices needs to be larger than that of metal-based devices, which limits the application of polymer-based devices. The advantages of magnesium-based alloys and iron-based alloys are easy processing and shaping, and high mechanical strength. However, due to the rapid corrosi...

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Problems solved by technology

In order to ensure that the iron-based alloy matrix is ​​completely corroded within a predetermined time, the amount of degradable polymer will be relatively large, because its degradation products are acidic, which will increase the risk of inflammatory reactions

In addition, when the type and properties of the degradable polymer are selected and the amount of the degradable polymer sufficient to completely corrode the iron-based alloy matrix is ​​determined, the corrosion rate of the iron-based alloy is too fast or the localized corrosion is severe. The structural integrity and mechanical properties of the alloy device in the early stage of implantation (1-6 months, that is, the recovery period mentioned above), which makes it difficult for the device to meet the requirements of clinical application

These defects are embodied in: (1) the degradation products of degradable polymers are acidic, and degradable polymers often have small molecule residues that degrade faster (such as the monomer residue standard of polylactic acid is <2%). Causes the iron-based alloy matrix to corrode quickly in the early stage of implantation, such as about 1-7 days after implantation into the coronary artery, the rapid corrosion and the accumulation of corrosion products lead to incomplete endothelialization of the inner surface of the device, increasing the risk of acute and subacute thrombosis ; (2) The uneven degradation of degradable polymers can easily lead to uneven corrosion of the iron-based alloy matrix, and local corrosion may cause fractures too quickly, which makes it difficult to meet the requirements of early structural integrity and mechanical properties

Although the method of reducing the amount of degradable polymers can be used to prevent the early corrosion of iron-based alloy devices, it will prolong the corrosion period of iron-based alloy devices

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