Bioabsorbable magnesium alloy with controlled multi-phase absorption
OwnerJacob Edick, Carolyn Woldringinventors
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Abstract
A bioabsorbable magnesium alloy for use in an orthopedic implant comprises magnesium, zinc in an amount of 0.5-4 weight percent, calcium in an amount of 0.1-1.5 weight percent, and manganese in an amount of up to 1.5 weight percent. The alloy exhibits a controlled, multi-phase absorption profile when exposed to physiological conditions, including an initial period of minimal degradation, followed by a steady-state phase, and concluding with an accelerated absorption phase. A method of manufacturing the alloy includes casting, solution treating, and extruding. An orthopedic implant device formed from the alloy comprises a body that exhibits the controlled, multi-phase absorption profile when implanted.
Claims20
A bioabsorbable magnesium alloy for use in an orthopedic implant, comprising:
- magnesium;
- zinc in an amount within a range from about 0.6 wt. % to about 5 wt. %;
- calcium in an amount within a range from about 0.2 wt. % to about 1.0 wt. %;
- and
- manganese in an amount within a range from about 0.4 wt. % to about 1.0 wt. %,
- wherein zinc and calcium are present in a weight ratio of at least 3:1,
- wherein the bioabsorbable magnesium alloy comprises a microstructure having a lower amount of Mg2Ca phase relative to ternary intermetallic phases, and
- wherein the bioabsorbable magnesium alloy exhibits a controlled, multi-phase absorption profile when exposed to physiological conditions, the controlled, multi-phase absorption profile comprising an initial period of minimal degradation, followed by a steady-state phase, and concluding with an accelerated absorption phase.
A method of manufacturing a bioabsorbable magnesium alloy for use in an orthopedic implant, comprising:
- casting an alloy comprising magnesium, zinc in an amount of 0.6 to 5 weight percent, calcium in an amount of 0.2 to 1.0 weight percent, and manganese in an amount of 0.7 to 1.0 weight percent to produce a cast alloy;
- solution treating the cast alloy at a temperature between 300° C. and 550° C. to produce a solution treated alloy;
- and
- extruding the solution treated alloy to form an extruded alloy having a microstructure with a lower amount of Mg2Ca phase relative to ternary intermetallic phases,
- wherein the extruded alloy exhibits a controlled, multi-phase absorption profile when exposed to physiological conditions.
An orthopedic implant device, comprising:
- a body formed from a bioabsorbable magnesium alloy, the bioabsorbable magnesium alloy comprising magnesium, zinc in an amount of 0.6 to 5 weight percent, calcium in an amount of 0.2 to 1.0 weight percent, and manganese in an amount of 0.7 to 1.0 weight percent,
- wherein the bioabsorbable magnesium alloy comprises a microstructure having an anode to cathode ratio of at least 20:1, and
- wherein the orthopedic implant device exhibits a controlled, multi-phase absorption profile when implanted, the controlled, multi-phase absorption profile comprising an initial period of minimal degradation lasting 7-14 days, followed by a steady-state phase lasting 2-8 weeks, and concluding with an accelerated absorption phase.
Dependencies are inferred from the claim text.