DEGRADABLE ZINC BASE ALLOY IMPLANT MATERIAL AND PREPARATION METHOD AND USE THEREOF

Abstract

Disclosed is a degradable zinc base alloy implant material comprising, by mass percentage content, 0.01 wt % to 14 wt % of Fe, 0 wt % to 13 wt % of functional elements and the remainder being Zn and a preparation method and use thereof. During preparation, Zn, Fe, and the functional elements are homogeneously mixed and placed into a high-purity graphite crucible and smelted together under a mixed gas atmosphere of SF.sub.6 and CO.sub.2. The mechanical properties of the zinc base alloy implant material have been significantly improved, so that the implant material is easy to process and shape, and so that the properties of strength and plasticity, etc., meet the basic requirements of human body implant materials, such as vascular stents, orthopedic internal fixation systems, and the like.

Claims

1. A degradable zinc base alloy implant material, which, comprises, by mass percentage content, 0.01 wt %-14 wt % of Fe, 0 wt %-13 wt % of functional elements, and the remainder being Zn; and preferably comprises 0.5 wt %-14 wt % of Fe and the remainder being Zn.

2. The zinc base alloy implant material according to claim 1, wherein, the functional elements include, but are not limited to, one or more of Sr, Cu, Ca, Ag, Mg, and Zr, and the mass percentages of the functional elements being: Sr: 0 wt %-13 wt % (preferably 0 wt %-8 wt %), Cu: 0 wt %-13 wt % (preferably 0 wt %-5 wt %), Ca: 0 wt %-5 wt %, Ag: 0 wt %-13 wt %, Mg: 0 wt %-13 wt %, and Zr: 0 wt %-13 wt %.

3. The zinc base alloy implant material according to claim 2, characterized by comprising 14 wt % of Fe, 0.01 wt %-2 wt % of Sr, and/or 0.01 wt %-3 wt % of Cu, and the remainder being Zn, and preferably comprising 14 wt % of Fe, 0.01 wt %-2 wt % of Sr, 0 wt %-3 wt % of Cu, and the remainder being Zn, and more preferably comprising 14 wt % of Fe, 0.1 wt %-1.5 wt % of Sr, 0.2 wt %-2 wt % of Cu, and the remainder being Zn; or further comprising 0.1 wt %-5 wt % of Ca, and more preferably comprising 14 wt % of Fe, 0.5 wt %-1.5 wt % of Sr, 0.1 wt %-0.5 wt % of Cu, 0.5 wt %-2 wt % of Ca, and the remainder being Zn; or further comprising 0.01 wt %-13 wt % of Mg and/or Ag, and more preferably comprising 14 wt % of Fe, 0.1 wt %-1 wt % of Ag, and the remainder being Zn.

4. The zinc base alloy implant material according to claim 2, characterized by containing 0.01 wt %-12 wt % of Fe (preferably 0.1 wt %-2 wt %), 0.01 wt %-2 wt % of functional elements, and the remainder being Zn, preferably the functional elements include 0.01 wt %-2 wt % of Cu, and more preferably contains 1 wt % of Fe, 1 wt % of Cu, and the remainder being Zn.

5. The zinc base alloy implant material according to claim 2, characterized by containing 0.01 wt %-2 wt % of Fe (preferably 0.1 wt %-2 wt %), 0.01 wt %-2 wt % of Sr, 0 wt %-5 wt % of Ca, and the remainder being Zn, and preferably containing 0.1 wt %-1.5 wt % of Fe, 0.1 wt %-1 wt % of Sr, 0.1 wt-1 wt % of Ca, and the remainder being Zn.

6. The zinc base alloy implant material according to claim 1, wherein the Zn, Fe, and functional elements are at purity higher than 99.99%, and the total content of impurities is 0.01%.

7. A method for preparing the zinc base alloy implant material according to claim 1, wherein Zn, Fe, and functional elements are homogeneously mixed by mass percentage content and placed into a high-purity graphite crucible, and smelted, drawn, and annealed under a mixed gas atmosphere of SF.sub.6 and CO.sub.2, to obtain the zinc base alloy implant material.

8. The method according to claim 7, wherein, the temperature of the annealing is 200 C.-500 C.

9. Use of the zinc base alloy implant material according to claim 1 or the zinc base alloy implant material prepared with the method according to claim 7 or 8 in preparation of a vascular stent, orthopedic implants, or implants in cavities and tracts, the cavities and tracts which include the oesophagus, biliary tract, urethra, and the like.

10. Use of the zinc base alloy implant material according to claim 1 in preparation of a vascular stent, wherein the vascular stent is used as a peripheral vascular stent and/or coronary vascular stent.

11. The use according to claim 10, wherein the zinc base alloy implant material comprises, by mass percentage content, 14 wt % of Fe, 0.01 wt %-3.0 wt % of Cu, and the remainder being Zn.

12. The use according to claim 10, wherein the zinc base alloy implant material comprises, by mass percentage content, 0.01 w %-2 wt % of Fe (preferably 0.1 w %-2 wt %), 0.01 wt %-2 wt % of Cu, and the remainder being Zn; preferably comprises 1 wt % of Fe, 1 wt % of Cu, and the remainder being Zn.

13. The use according to claim 10, wherein the surface of the zinc base alloy implant material is coated with anti-proliferative drug coating.

14. The use according to claim 13, wherein the anti-proliferative drug is paclitaxel or a derivative thereof, or rapamycin or a derivative thereof.

15. The use according to claim 13, wherein the drug coating is a layer of degradable polymer that contains the anti-proliferative drug, and the degradable polymer is one or more of polylactide, poly-L-lactic acid, polylactone, polycarbonate, polyamino acid, chitosan, and sulfonated chitosan.

16. The use according to claim 10, wherein the method of preparing a vascular stent comprises: mixing Zn, Fe, and the functional elements homogeneously by mass percentage content, and having the mixture placed into a high-purity graphite crucible, and smelted, drawn, and annealed under a mixed gas atmosphere of SF.sub.6 and CO.sub.2, to obtain the zinc base alloy implant material in a tubular form; and then treating the zinc base alloy implant material by laser engraving, polishing, spraying with drug coating, and crimping, to obtain the vascular stent.

17. Use of the zinc base alloy implant material according to claim 1 in preparation of an orthopedic implant.

18. The use according to claim 17, wherein the zinc base alloy implant material comprises, by mass percentage content, 0.01 wt %-2 wt % of Fe (preferably 0.1 w %-2 wt %), 0.01 wt %-2 wt % of Sr, and 0 wt %-5 wt % of Ca, and the remainder being Zn, and preferably comprises 0.1 wt %-1.5 wt % of Fe, 0.1 wt %-1 wt % of Sr, 0.1 wt %-1 wt % of Ca, and the remainder being Zn.

19. The use according to claim 17, wherein the zinc base alloy implant material comprises, by mass percentage content, 14 wt % of Fe, 0.01 wt %-2 wt % of Sr, 0 wt %-3 wt % of Cu, and the remainder being Zn, and preferably comprises 14 wt % of Fe, 0.1 wt %-1.5 wt % of Sr, 0.2 wt %-2 wt % of Cu, and the remainder being Zn.

20. The use according to claim 19, wherein the zinc base alloy implant material further comprises, by mass percentage content, 0.1 wt %-5 wt % of Ca, and preferably comprises 14 wt % of Fe, 0.5 wt %-1.5 wt % of Sr, 0.1 wt %-0.5 wt % of Cu, 0.5 wt %-2 wt % of Ca, and the remainder being Zn.

21. The use according to claim 19, wherein the zinc base alloy implant material further comprises, by mass percentage content, 0.01 wt %-13 wt % of Mg and/or Ag and preferably comprises 14 wt % of Fe, 0.1 wt %-1 wt % of Ag, and the remainder being Zn.

22. The application according to claim 17, wherein the method of preparing an orthopedic implant comprises: mixing Zn, Fe, and the functional elements homogeneously by mass percentage content, and having the mixture placed into a high-purity graphite crucible, and smelted, drawn, and annealed under a mixed gas atmosphere of SF.sub.6 and CO.sub.2, to obtain the zinc base alloy implant material in a tubular form; and treating the zinc base alloy implant material by engraving and polishing, to obtain the orthopedic implant.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0044] FIG. 1 is a schematic diagram of the shape of the zinc base alloy implant material in embodiment 1, which is used for a coronary vascular stent;

[0045] FIG. 2 is an enlarged view of the engraved pattern on the zinc base alloy implant material in the embodiment 1;

[0046] FIG. 3 is a coronary angiogram taken when the zinc base alloy implant material in the embodiment 1 is used as a vascular stent;

[0047] FIG. 4 is an HE stain image of a section taken when the zinc base alloy implant material in the embodiment 1 is used as a vascular stent;

[0048] FIG. 5 is a schematic diagram of the shape of the zinc base alloy implant material in embodiment 4, which is used for an orthopedic implant.

DETAILED DESCRIPTION OF THE EMBODIMENTS

[0049] The degradable zinc base alloy implant material provided in the present invention contains, by mass percentage content, 73 wt %-99.99 wt % Zn, 0.01 wt %-14 wt % of Fe, and 0 wt %-1-3 wt % of functional elements. The functional elements may be selected from one or more of Sr, Cu, Ca, Ag, Mg, and Zr; the mass percentages of the functional elements in the zinc base alloy implant material are: Sr: 0 wt %-13 wt % (preferably 0 wt %-8 wt %), Cu: 0 wt %-13 wt % (preferably 0 wt %-5 wt %), Ca: 0 wt %-5 wt %, Ag: 0 wt %-13 wt %, Mg: 0 wt %-13 wt %, and Zr: 0 wt %-13 wt %. Preferably, in the zinc base alloy implant material, the content of Fe is 0.01 wt %-2 wt %, the content of Cu is 0.01 wt %-2 wt %, the total content of other functional elements is <0.1 wt %, with Zn accounting for the remaining content, and the total content of impurities is <0.01 wt %. More preferably the content of Fe is 0.1 wt %-2 wt %. The Zn, Fe, and functional elements in the zinc base alloy implant material are at purity higher than 99.99%, and the total content of impurities is 0.01%. The inclusion of Al impurities must be avoided because Al and Fe form FeAl intermetallic compounds, which impact the subsequent processing (mainly polishing).

[0050] The method for preparing the degradable zinc base alloy implant material in the present invention comprises the following steps:

[0051] Zn and Fe, or Zn, Fe, and functional elements are homogeneously mixed by mass percentage content, placed into a high-purity graphite crucible, smelted, drawn, and annealed under a mixed gas atmosphere of SF.sub.6 and CO.sub.2 to obtain the zinc base alloy implant material. Finally, the zinc base alloy implant material is processed into a required shape.

[0052] Hereunder the present invention will be further detailed in embodiments, but those embodiments should not be understood as constituting any limitation to the present invention.

[0053] The methods used in the following embodiments are conventional methods, unless otherwise specified. The percentage values are mass percentage values, unless otherwise specified.

Embodiment 1: ZnFeCu Alloy

[0054] The degradable zinc base alloy implant material in this embodiment was a ZnFeCu alloy. Specifically, the preparation process comprised the following steps:

[0055] 1) 1 wt % of Fe, 1 wt % of Cu, and the remainder was Zn (the total content of impurities was <0.001 wt %) by mass percentage content were placed into a high-purity graphite crucible, mixed, and smelted in shielding gas SF.sub.6 (1 vol %) and CO.sub.2, to obtain a zinc base alloy.

[0056] 2) After smelting, the obtained zinc base alloy was extruded into a rod of 10 mm diameter and 50 cm length.

[0057] 3) The obtained rod was annealed (at 200 C.-500 C. temperature, for 30 min.) and drawn several times into a tubular product with a 0.15 mm0.013 mm outer diameter and 0.1 mm0.013 mm wall thickness, the tubular product was designed into a stent with 3.020 patterns. The stent was formed by femtosecond laser engraving (the engraving patterns are shown in FIG. 1), and was polished by electrochemical polishing so that the edges and corners became smooth. Then, the stent was to be used as a coronary vascular stent. The stem width of the prepared stent was 0.1 mm, and the specific surface area of the blank portion was 20%. An enlarged view of the engraving patterns is shown in FIG. 2.

[0058] 4) Finally, the surface of the stent was coated with drug coating by spraying or impregnation, and then the scaffold was crimped to a delivery system, sterilized, and packed; thus, a coronary vascular stent was obtained; the drug may be selected from rapamycin and its derivatives, or paclitaxel and its derivatives, and then coated to complete fabrication.

Effect Verification:

[0059] The zinc base alloy implant material obtained with the above-mentioned preparation method had a yield strength of about 243 MPa, a tensile strength of about 264 MPa, and a specific elongation up to 22%. It could adapt to the processing and application procedures of scaffold crimping and expansion, and was a coronary vascular stent material with ideal mechanical properties. The load bearing strength of the prepared coronary vascular stent was 1.8N after it was expanded to the nominal diameter and then compressed to 90%, and met the clinical application requirement. The degradation rate measured by the method specified in ASTM_G31-72 was 0.23 mm/a; The hemolysis characteristics were measured by the series method according to GB16886, and the hemolysis rate was 1%, which was lower than the value (5%) specified in the standard. The level of cytotoxicity was grade I, there was no intracutaneous irritation, and the sensitization ratio was 0%.

[0060] Measured in an anti-microbial performance test according to Appendix A of QB/T2591-2003 Anti-Microbial PlasticsTest for Anti-Microbial Activity and Efficacy, the anti-microbial ratios against staphylococcus aureus and escherichia coli were 92% and 94% respectively, which were judged as anti-microbial according to Table 1 in Subsection 5.1 in the standard.

[0061] The vascular stent was loaded to a delivery system and then applied in an animal model (Shanghai white pig, male, castrated, 23 kg), the result of coronary angiography and the HE staining result of a section taken after one month were observed, as shown in FIGS. 3 and 4. As seen in the figures, the zinc base alloy implant material provided in the present invention exhibited excellent development and throughput performance when it was used as a vascular stent. The result of analysis demonstrated that there was no chronic inflammation (an inducement of intermittent immunologic reactions), thrombus in the stent, or scaffold stem breakage, etc., after the vascular stent was implanted. Therefore, the zinc base alloy implant material was a degradable vascular stent material that had wide application prospects.

Embodiment 2: ZnFeCu Alloy

[0062] The degradable zinc base alloy implant material in this embodiment was a ZnFeCu alloy, which contained 0.14 wt % of Fe, 1.8 wt % of Cu, and the remainder was Zn, the total content of impurities was controlled to be <0.001 wt %, and the preparation process was the same as that in embodiment 1.

Effect Verification:

[0063] The zinc base alloy implant material obtained with the above-mentioned preparation method had an elastic modulus of 75 GPa, a yield strength of 210 MPa, and a tensile strength of 240 MPa. It could adapt to the processing and application procedures of stent crimping and expansion, and was a coronary vascular stent material with ideal mechanical properties. The degradation rate measured by the method specified in ASTM_G31-1972 was 0.19 mm/a. The hemolysis characteristics were measured by the series method according to GB16886, and the hemolysis ratio was 1%, which was lower than the value (5%) specified in the standard. The level of cytotoxicity was grade I, there was no intracutaneous irritation, and the sensitization ratio was 0%.

Embodiment 3: ZnFeSrCa Alloy

[0064] The degradable zinc base alloy implant material in this embodiment was a ZnFeSrCa alloy, which contained 0.5 wt % of Fe, 0.5 wt % of Sr, 0.5 wt % of Ca; the remainder was Zn; and the preparation process was the same as that in the embodiment 1.

Effect Verification:

[0065] The zinc base alloy implant material obtained with the above-mentioned preparation method had an elastic modulus of 80 GPa, a yield strength of 233 MPa, and a tensile strength of 270 MPa, and could meet the requirement for mechanical properties for fixation of fractured bones at load bearing positions. The degradation rate measured with the method specified in ASTM_G31-1972 was 0.38 mm/a. When tested with the methods specified in GB16886 there was no obvious cytotoxicity, intracutaneous irritation, sensitization, or genotoxicity was found. Since the elastic modulus of the zinc base alloy implant material (6070 Gpa) was closer to the elastic modulus of cortical bones of the human body (about 20 Gpa) than conventional internal fixation materials (>100 Gpa), the zinc base alloy implant material could avoid the stress shielding effect of orthopedic implants on normal human bones, and could promote bone knitting.

Embodiment 4: ZnFeSrCa Alloy

[0066] The degradable zinc base alloy implant material in this embodiment was a ZnFeSrCa alloy, which contained 0.8 wt % of Fe, 1 wt % of Sr, 1 wt % of Ca, and the remainder is Zn.

[0067] Specifically, the preparation process comprised the following steps:

[0068] 1) 0.8 wt % of Fe, 1 wt % of Sr, 1 wt % of Ca, and the remainder was Zn (the total content of impurities was <0.001 wt %) by mass percentage content were loaded into a high-purity graphite crucible and mixed and smelted in shielding gas SF.sub.6 (1 vol %), to obtain a zinc base alloy.

[0069] 2) After the smelting, the obtained zinc base alloy was extruded into a rod of 5 mm diameter and 50 cm length.

[0070] 3) The obtained rod was engraved and polished on a CNC machine tool into a straight bone nail shape as shown in FIG. 5. The dimensions were shown in Table 1.

TABLE-US-00001 TABLE 1 Dimensions of the Orthopedic Implant in Embodiment 1 Diameter d.sub.1.sub.0.15.sup.0 d.sub.5.sub.0.15.sup.0 e P r.sub.4 r.sub.5 mm mm mm mm mm mm 5 mm 2.7 2.1 0.1 1.0 0.3 0.05 35 3

Effect Verification:

[0071] The zinc base alloy implant material obtained with the above-mentioned preparation method had an elastic modulus of 64 GPa, a yield strength of 254 MPa, and a tensile strength of 270 MPa, and could meet the requirement for mechanical properties for fixation of bone fractures at load bearing positions. The degradation rate measured with the method specified in ASTM_G31-1972 was 0.30 mm/a; when tested with the methods specified in GB16886, no obvious cytotoxicity, intracutaneous irritation, sensitization, or genotoxicity was found. Since the elastic modulus of the zinc base alloy implant material (6070 Gpa) was closer to the elastic modulus of cortical bones of human body (about 20 Gpa) than to conventional internal fixation materials (>100 Gpa), the zinc base alloy implant material could avoid the stress shielding effect of an orthopedic implants on human bones, and could promote bone knitting.

Embodiment 5: ZnFe Alloy

[0072] The degradable zinc base alloy implant material in this embodiment was a ZnFe alloy, which contained 0.14 wt % of Fe, and the remainder was Zn; the total content of impurities was <0.001 wt % and the preparation process was the same as that in embodiment 1.

Embodiment 6: ZnFe Alloy

[0073] The degradable zinc base alloy implant material in this embodiment was a ZnFe alloy, which contained 0.7 wt % of Fe, and the remainder was Zn; the total content of impurities was <0.001% and the preparation process was the same as that in embodiment 1.

Embodiment 7: ZnFe Alloy

[0074] The degradable zinc base alloy implant material in this embodiment was a ZnFe alloy, which contained 0.35 wt % of Fe, and the remainder was Zn; the total content of impurities was <0.001% and the preparation process was the same as that in embodiment 1.

Embodiment 8: ZnFe Alloy

[0075] The degradable zinc base alloy implant material in this embodiment was a ZnFe alloy, which contained 0.2 wt % of Fe, and the remainder was Zn; the total content of impurities was <0.001% and the preparation process was the same as that in embodiment 1.

Embodiment 9: ZnFe Alloy

[0076] The degradable zinc base alloy implant material in this embodiment was a ZnFe alloy, which contained 14 wt % of Fe, and the remainder was Zn; the total content of impurities was <0.001% and the preparation process was the same as that in embodiment 1.

Embodiment 10: ZnFe Alloy

[0077] The degradable zinc base alloy implant material in this embodiment was a ZnFe alloy, which contained 10 wt % of Fe, and the remainder was Zn; the total content of impurities was <0.001% and the preparation process was the same as that in embodiment 1.

Embodiment 11: ZnFeSrCa Alloy

[0078] The degradable zinc base alloy implant material in this embodiment was a ZnFe alloy, which contained 2 wt % of Fe, 2 wt % of Sr, 5 wt % of Ca, and the remainder was Zn; the total content of impurities was <0.001% and the preparation process was the same as that in embodiment 1.

Embodiment 12: ZnFeCu Alloy

[0079] The degradable zinc base alloy implant material in this embodiment was a ZnFe alloy, which contained 2 wt % of Fe, 2 wt % of Cu, and the remainder was Zn; the total content of impurities was <0.001% and the preparation process was the same as that in embodiment 1.

Embodiment 13: ZnFe Alloy

[0080] The degradable zinc base alloy implant material in this embodiment was a ZnFe alloy, which contained 0.5 wt % of Fe, and the remainder was Zn; the total content of impurities was <0.001% and the preparation process was the same as that in embodiment 1.

Embodiment 14: ZnFeCu Alloy

[0081] The degradable zinc base alloy implant material in this embodiment was a ZnFeCu alloy, which contained 2.0 wt % of Fe, 0.1 wt % of Cu, and the remainder was Zn; the total content of impurities was <0.001 wt % and the preparation process was the same as that in embodiment 1.

Embodiment 15: ZnFeCu Alloy

[0082] The degradable zinc base alloy implant material in this embodiment was a ZnFeCu alloy, which contained 10.0 wt % of Fe, 2.0 wt % of Cu, and the remainder was Zn; the total content of impurities was <0.001 wt % and the preparation process was the same as that in embodiment 1.

Embodiment 16: ZnFeCu Alloy

[0083] The degradable zinc base alloy implant material in this embodiment was a ZnFeCu alloy, which contained 12.0 wt % of Fe, 3.0 wt % of Cu, and the remainder was Zn; the total content of impurities was <0.001 wt % and the preparation process was the same as that in embodiment 1.

Embodiment 17: ZnFeCu Alloy

[0084] The degradable zinc base alloy implant material in this embodiment was a ZnFeCu alloy, which contained 5.0 wt % of Fe, 3.0 wt % of Cu, and the remainder was Zn; the total content of impurities was <0.001 wt % and the preparation process was the same as that in embodiment 1.

Embodiment 18: ZnFeCuSr Alloy

[0085] The degradable zinc base alloy implant material in this embodiment was a ZnFeCuSr alloy, which contained 14 wt % of Fe, 1.8 wt % of Cu, 1 wt % of Sr, and the remainder was Zn; the total content of impurities was <0.001 wt % and the preparation process was the same as that in embodiment 4.

Embodiment 19: ZnFeCuSrCa Alloy

[0086] The degradable zinc base alloy implant material in this embodiment was a ZnFeCuSrCa alloy, which contained 14 wt % of Fe, 0.2 wt % of Cu, 1 wt % of Sr, 1 wt % of Ca, and the remainder was Zn; the total content of impurities was <0.001 wt % and the preparation process was the same as that in embodiment 4.

Embodiment 20: ZnFeAg Alloy

[0087] The degradable zinc base alloy implant material in this embodiment was a ZnFeAg alloy, which contained 14 wt % of Fe, 0.5 wt % of Ag, and the remainder was Zn; the total content of impurities was <0.001 wt % and the preparation process was the same as that in embodiment 4.

[0088] Reference example 1 (ZnFeCu alloy with Fe content higher than 14%): a zinc base alloy implant material was obtained with the preparation method disclosed in the present invention, wherein, the zinc base alloy implant material contained 16 wt % of Fe, 1 wt % of Cu, and the remainder was Zn.

[0089] Reference example 2 (ZnCu alloy with Fe content lower than 0.1%): a zinc base alloy implant material was obtained with the preparation method disclosed in the present invention, wherein, the zinc base alloy implant material contained 1 wt % of Cu, 0.001 wt % of Fe, and the remainder was Zn.

[0090] Reference example 3 (ZnFeCu alloy with the content of functional components (Cu) higher than 13%): a zinc base alloy implant material was obtained with the preparation method disclosed in the present invention, wherein, the zinc base alloy implant material contained 14 wt % of Cu, 1 wt % of Fe, and the remainder was Zn.

[0091] Reference example 4 (ZnFeCuSrCa alloy with Fe content higher than 14%): a zinc base alloy implant material was obtained with the preparation method disclosed in the present invention, wherein, the zinc base alloy implant material contained 16 wt % of Fe, 1 wt % of Cu, 8 wt % of Sr, 8 wt % of Ca, and the remainder was Zn.

[0092] Reference example 5 (zinc base alloy without Fe in the prior art): a zinc base alloy implant material was obtained with the preparation method disclosed in Patent Application No. CN103736152A, wherein, the zinc base alloy implant material contained 0.1 wt % Ce, 0.5 wt % of Mg, 0.1 wt % of Ca, 1.5 wt % of Cu, and the remainder was Zn.

[0093] Reference example 6 (ZnFe alloy with Fe content higher than 14%): a zinc base alloy implant material was obtained with the preparation method disclosed in the present invention, wherein, the zinc base alloy implant material contained 17 wt % of Fe, and the remainder was Zn.

[0094] Reference example 7 (zinc material without Fe): a zinc base alloy implant material was obtained with the preparation method disclosed in the present invention, wherein, the zinc base alloy implant material only contained Zn and 1 wt % of Cu, without any other elements.

[0095] The zinc base alloy implant materials obtained in the embodiments 1-20 were fabricated for use in vascular stents, orthopedic implants, or degradable implants in the oesophagus, biliary tract, urethra, or other cavities or tracts. The mechanical properties and corrosion resistance property ((ASTM-G31-72), Hank's simulated body fluid, 37 C.) of the zinc base alloy implant materials are shown in Table 2. The mechanical properties and corrosion resistance property of the zinc base alloy implant materials obtained in the reference examples 1-7 are also shown in Table 2.

TABLE-US-00002 TABLE 2 Mechanical Properties and Corrosion Resistance Property of the Implant Materials in Embodiments 1-20 and Reference Examples 1-7 Yield strength, Tensile Elastic Specific Corrosion Embodiment MPa strength, MPa modulus, GPa elongation, % rate Embodiment 1 243 264 70 22 0.23 mm/a Embodiment 2 210 240 75 12 0.19 mm/a Embodiment 3 233 270 80 12 0.38 mm/a Embodiment 4 254 270 64 20 0.30 mm/a Embodiment 5 215 242 78 22 0.20 mm/a Embodiment 6 200 270 76 18 0.26 mm/a Embodiment 7 202 234 82 16 0.28 mm/a Embodiment 8 243 267 77 24 0.18 mm/a Embodiment 9 156 172 83 12 0.20 mm/a Embodiment 10 165 188 80 13 0.24 mm/a Embodiment 11 214 232 85 13 0.33 mm/a Embodiment 12 207 219 77 17 0.42 mm/a Embodiment 13 205 249 72 16 0.45 mm/a Embodiment 14 203 222 80 17 0.31 mm/a Embodiment 15 189 234 83 12 0.20 mm/a Embodiment 16 183 234 82 18 0.22 mm/a Embodiment 17 177 190 77 16 0.20 mm/a Embodiment 18 218 268 74 13 0.18 mm/a Embodiment 19 223 243 66 8 0.20 mm/a Embodiment 20 169 188 71 14 0.21 mm/a Reference 200 266 89 8 0.17 mm/a Example 1 Reference 30 60 77 3 0.32 mm/a Example 2 Reference 202 241 76 25 0.09 mm/a Example 3 Reference 229 249 92 5 0.11 mm/a Example 4 Reference 221 234 77 4 0.15 mm/a Example 5 Reference 207 256 70 3 0.08 mm/a Example 6 Reference 179 224 65 11 0.08 mm/a Example 7

[0096] The results in Table 2 indicated that the mechanical strength (yield strength and tensile strength), elastic property (elastic modulus), and extensibility (specific elongation) of the degradable zinc base alloy implant material provided in the present invention met the requirements for load bearing capacity and processability of implanted stents. In addition, the degradation rate (corrosion rate) of the material was ideal (0.15 mm/a-0.45 mm/a), and the material could be used as a degradable in-vivo implant material. Tested with the method specified in ISO10993, the materials in the embodiments 1-20 had grade II cytotoxicity (i.e., no obvious cytotoxicity), to not cause any intracutaneous irritation or sensitization, and had no genotoxicity.

[0097] Compared with the zinc base alloy implant material provided in the present invention, the materials in the reference examples 1-7 had mechanical strength that was too low (e.g., in the reference example 2) for them to be used as implants that must meet a specific load bearing capacity requirements; or they had an elastic modulus that had an excessively high difference from the elastic modulus of human bones (e.g., in reference examples 1 and 4), causing a stress shielding effect that may result in side effects such as delayed bone knitting and mismatch effects, etc.; or they had a degradation rate that was too low (e.g., in reference examples 3, 4, 6 and 7) for them to meet the clinical requirement for material degradation; or they had extremely low specific elongation (<10%), resulting in excessively high material brittleness (e.g., in reference examples 1, 2, and 4-6), poor processability, high frangibility, and application risks and inconvenience.

INDUSTRIAL APPLICABILITY

[0098] The degradable zinc base alloy implant material provided in the present invention increases the degradation rate of the zinc component by forming a micro-electrode between the zinc and iron, has significantly improved mechanical properties so that it can be easily processed and shaped, and has strength and plasticity property that meet the basic requirements for implanted materials in human body, such as vascular stents and orthopedic internal fixation systems, etc. Therefore, the degradable zinc base alloy implant material provided in the present invention is suitable for industrial application.