Absorbable iron-base alloy implantable medical device and preparation method thereof

Abstract

The invention discloses an absorbable iron-base alloy implantable medical device and a preparation method thereof. The absorbable iron-base alloy implantable medical device comprises an iron-base alloy matrix, a degradable polymer arranged at the surface of the iron-base alloy matrix and an alkaline protector arranged at the surface of the iron-base alloy matrix. The alkaline protector contains at least one alkaline substance; during the early stage of implantation of the device, the alkaline substance can be neutralized with an acidic substance generated by a polymer so as to retard corrosion of the iron-base alloy matrix at the early stage of implantation, so that the iron-base alloy matrix is basically non-corroding or slow in corrosion during the early stage of implantation, and meets the clinical requirements on mechanical properties of the device at the early stage of implantation. Furthermore, the alkaline protector is consumed by neutralizing to expose the matrix, the matrix still can be eroded more quickly in an acidic environment formed by polymers and thus clinically meets the requirement on the corrosion period of the device.

Description

technical field [0001] The invention relates to the field of medical devices, in particular to an absorbable iron-based alloy implanted medical device and a preparation method thereof. Background technique [0002] Currently, the most widely used materials for absorbable implantable medical device substrates 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. The degradation products are carbon dioxide and water. The size of the base device 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 that they are easy to process and shape, and have high mechanical strength. However, the corrosion rate of magnesium-based alloys in the human body is too fast and hydrogen gas will be generated with the corrosion, which can onl...

AI Technical Summary

Problems solved by technology

When the type and properties of degradable polyester are selected and the amount of degradable polyester sufficient to completely corrode the iron-based alloy substrate is determined, the iron-based alloy corrosion rate is too fast or the local corrosion is severe, which will affect the iron-based alloy device Structural integrity and mechanical properties 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 in the early stage of implantation

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

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

Images