Properties and parameters of novel biodegradable metallic alloys

Patent metadata

Field	Value
Publication number	US-2023313346-A1
Application number	US-202318099384-A
Country	US
Kind code	A1
Filing date	Jan 20, 2023
Priority date	Apr 12, 2017
Publication date	Oct 5, 2023
Grant date	—

Abstract

The invention relates to biodegradable, metal alloys, methods for their preparation and applications for their use. The alloys include magnesium and other components, such as, yttrium, calcium, zirconium, and zinc. These elements are alloyed together in specific combinations and amounts in order to achieve an alloy having desired properties and characteristics. In certain embodiments, strontium or cerium may be included as an additive. The resulting alloys are particularly suitable for forming various medical devices for implantation into the body of a patient.

First claim

1 . A method of preparing a biodegradable medical implant device, comprising:
preparing a biodegradable metal alloy, comprising:
melting about 4.0 weight percent of yttrium, from about 0.5-0.6 weight percent of calcium, from about 0.6-1.0 weight percent of zirconium, about 2.0 weight percent of zinc, and a balance of magnesium including impurities, based on the total weight of the composition, to form a melted mixture; and
casting the melted mixture, comprising:
pouring the melted mixture into a mold; and
allowing the melted mixture to cool and solidify.

2 . The method of claim 1 , wherein the pouring step comprises the molten mixture being poured into a steel/copper mold at room temperature to 500° C.

3 . The method of claim 1 , further comprising a heat treatment step following one or more of the melting and casting steps, at a temperature from about 250° C. to 350° C.

4 . The method of claim 1 , wherein prior to solidification, the melted mixture is tested to determine the amounts of yttrium, calcium, zirconium, zinc, and magnesium, and the amounts are adjusted as desired.

5 . The method of claim 1 , wherein one or more of the melting and casting steps is performed under a protective atmosphere to preclude, minimize, or reduce oxidation/decomposition of the magnesium.

6 . The method of claim 1 , wherein following casting, performing extrusion at an extrusion ratio from about 10 to 700 and a temperature from about 350° C. to 450° C.

7 . The method of claim 6 , wherein the extrusion ratio is from about 10 to 100.

8 . A biodegradable medical implant device, comprising:
a metal alloy, comprising: from about 4.0-4.5 weight percent of zinc; from about 0.3-0.5 weight percent of zirconium; and a balance of magnesium including impurities, based on the total weight of the composition.

9 . The device of claim 8 , wherein the zinc constitutes about 4.0 weight percent and the zirconium constitutes about 0.5 weight percent.

10 . The device of claim 8 , wherein the zinc constitutes about 4.4 weight percent and the zirconium constitutes from about 0.3-0.4 weight percent.

11 . The device of claim 8 , further comprising an element selected from the group consisting of strontium and cerium.

12 . The device of claim 11 , wherein the element constitutes from about 0.25-1.0 weight percent of the metal alloy.

13 . The device of claim 8 , wherein the metal alloy has an average grain size from about 50 to about 100 µm.

14 . The device of claim 8 , wherein the metal alloy forms a primary phase of Mg(ZnZr), and an intermetallic secondary phase of Mg 7 Zn 3 precipitate is minimized or precluded in the metal alloy.

15 . The device of claim 8 , wherein the metal alloy comprises one or more of:
from about 1.0 to about 9.0 weight percent aluminum; from about 0.1 to about 1.0 weight percent manganese; and from about 0.25 to about 1.0 weight percent silver, based on the total weight of the metal alloy.

16 . A method of preparing a biodegradable medical implant device, comprising:
preparing a biodegradable metal alloy, comprising:
melting from about 4.0-4.5 weight percent of zinc, from about 0.3-0.5 weight percent of zirconium, and a balance of magnesium including impurities, based on the total weight of the composition, to form a melted mixture; and
casting the melted mixture, comprising:
pouring the melted mixture into a mold; and
allowing the melted mixture to cool and solidify.

17 . The method of claim 16 , further comprising a heat treatment step following one or more of the melting and casting steps, at a temperature from about 250° C. to 350° C.

18 . The method of claim 16 , wherein prior to solidification, the melted mixture is tested to determine the amounts of yttrium, calcium, zirconium, zinc, and magnesium, and the amounts are adjusted as desired.

19 . The method of claim 16 , wherein one or more of the melting and casting steps is performed under a protective atmosphere to preclude, minimize, or reduce oxidation/decomposition of the magnesium.

20 . The method of claim 16 , wherein following casting, performing extrusion at an extrusion ratio from about 10 to 700 and a temperature from about 350° C. to 450° C.

Assignees

• Univ Pittsburgh Commonwealth Sys Higher Education

Inventors

• Kumta Prashant N

Classifications

• C22C23/06 Primary

  with a rare earth metal as the next major constituent · CPC title

• A61L27/58 Primary

  Materials at least partially resorbable by the body · CPC title

• A61L27/047

  Other specific metals or alloys not covered by A61L27/042 - A61L27/045 or A61L27/06 · CPC title

• C22C23/04

  with zinc or cadmium as the next major constituent · CPC title

• A61L31/148

  Materials at least partially resorbable by the body · CPC title