Original Title: Brief Introduction to the US FDA Guidelines on Key Points for Non-clinical Evaluation of Medical Devices Containing Nitinol Brief Introduction of FDA's Guideline on Nonclinical Evaluation of Medical Devices Containing Nitinol In October 2020, FDA of the United States issued the Guidelines for Non-clinical Evaluation of Medical Devices Containing Nitinol, which elaborated the key points of technical review of medical devices containing Nitinol. The contents of the Guidelines are briefly introduced as follows. I. Basic Concepts Nitinol is a near-equiatomic alloy of nickel and titanium, which has the properties of superelasticity and shape memory, and is widely used in cardiovascular devices such as heart stents, valves, guidewires, and other fields of medical devices. Compared with traditional metals such as stainless steel, titanium or cobalt-chromium alloys, nickel-titanium alloys have complex properties and are susceptible to many factors such as alloy composition, thermal processing, surface treatment, corrosion of biological tissues and so on. When evaluating its safety and effectiveness, it is necessary to focus on thermodynamic properties, process sensitivity and so on. II. Key points of technical evaluation (I) Basic information 1. Material composition If the material of the nickel-titanium alloy used in the device conforms to a recognized standard, it shall be specified in the application (e.g., ASTM F2063). If the material does not conform to a recognized standard, the composition of the material shall be defined and its properties shall be described. 2. Manufacturing process The production process flow diagram shall be provided, especially the thermal process, surface treatment steps, final cleaning steps, etc. 3. Superelastic/shape memory properties At operating temperatures, superelasticity or shape memory can be achieved by adjusting the composition and heat treatment of the nitinol alloy. Due to the large difference in properties between the two, the applicant should specify in the application which properties (superelasticity or shape memory) of the nickel-titanium alloy are used. 4. Deformation temperature The change of temperature will affect the mechanical property of nickel-titanium alloy. It is recommended to specify the phase transformation temperature of the finished product in the data. Refer to ASTM F2004 and ASTM F2082. (II) Mechanical test 1. Key points of experiment It is recommended to explain the control mode adopted for mechanical testing; for deformable implantable devices, it is recommended to consider clinical deformation and temperature drift before mechanical testing; mechanical testing should be carried out at actual clinical temperature; if fatigue testing is carried out, it is recommended to use clinically relevant solvents (such as PBS); If the shape memory properties of the device are utilized, it is recommended that shape memory testing be performed at clinical temperatures and service cycles, and that functional properties and device integrity be evaluated. 2. Stress calculation/strain analysis If a computational analysis is performed, an appropriate metal model should be used to correctly reflect the thermodynamic properties of the nitinol alloy. A material model may be selected by reference to ASTM F2516. The applicant shall verify the calculation model. If the device is subjected to a cyclic load test, the fatigue safety factor shall also be calculated. Expand the full text (III) Corrosion resistance test 1. Pitting Corrosion of nitinol alloys can result in the release of nickel ions and affect the integrity of the device. The corrosion resistance depends on the manufacturing process and surface treatment. Pitting corrosion testing is recommended in accordance with ASTM F2129. 2. Release of nickel ion If Nitinol devices do not meet the accepted criteria for corrosion resistance, or do not use a proven surface treatment process, a nickel ion release test should be considered. Refer to ASTM F3306 for test methods. 3. Galvanic corrosion If Nitinol devices are expected to be in contact with dissimilar metals, consideration should be given to performing a galvanic corrosion test, as recommended in ASTM F3044. (IV) Biocompatibility It is recommended to refer to ISO 10993 -1 for biocompatibility evaluation. If a nickel ion release test is performed, refer to ISO 10993 -17. (V) Label information It is recommended that the label clearly indicate that the device contains nitinol, suggesting that it may cause allergic reactions in patients, nickel titanium wire , especially in long-term or permanent implanted devices. III. References: [1] FDA. Technical Considerations for Non-Clinical Assessment of MedicalDevices Containing Nitinol - Guidance for Industry and Food and Drug Administration Staff. October 15, 2020 Labels: Medical Device FDA Registration, US Medical Device GMP Certification Release date: 2021-07-06 20:07 Views: 27 In October 2020, FDA of the United States issued the Guidelines for Non-clinical Evaluation of Medical Devices Containing Nitinol, which elaborated the key points of technical review of medical devices containing Nitinol. The contents of the Guidelines are briefly introduced as follows. Brief Introduction of FDA's Guideline on Nonclinical Evaluation of Medical Devices Containing Nitinol In October 2020, FDA of the United States issued the Guidelines for Non-clinical Evaluation of Medical Devices Containing Nitinol, which elaborated the key points of technical review of medical devices containing Nitinol. The contents of the Guidelines are briefly introduced as follows. I. Basic Concepts Nitinol is a near-equiatomic alloy of nickel and titanium, which has the properties of superelasticity and shape memory, and is widely used in cardiovascular devices such as heart stents, valves, guidewires, and other fields of medical devices. Compared with traditional metals such as stainless steel, titanium or cobalt-chromium alloys, nickel-titanium alloys have complex properties and are susceptible to many factors such as alloy composition, thermal processing, surface treatment, corrosion of biological tissues and so on. When evaluating its safety and effectiveness, it is necessary to focus on thermodynamic properties, process sensitivity and so on. II. Key Points of Technical Evaluation (I) Basic information 1. Material composition If the material of the nickel-titanium alloy used in the device conforms to a recognized standard, it shall be specified in the application (e.g., ASTM F2063). If the material does not conform to a recognized standard, the composition of the material shall be defined and its properties shall be described. 2. Manufacturing process The production process flow diagram shall be provided, especially the thermal process, surface treatment steps, final cleaning steps, etc. 3. Superelastic/shape memory properties At operating temperatures, superelasticity or shape memory can be achieved by adjusting the composition and heat treatment of the nitinol alloy. Due to the large difference between the two properties, the applicant should specify in the application which property (superelasticity or shape memory) of the nickel-titanium alloy is used. 4. Deformation temperature The change of temperature will affect the mechanical property of nickel-titanium alloy. It is recommended to specify the phase transformation temperature of the finished product in the data. Refer to ASTM F2004 and ASTM F2082. (II) Mechanical test 1. Key points of experiment It is recommended to explain the control mode adopted for mechanical testing; for deformable implantable devices, it is recommended to consider clinical deformation and temperature drift before mechanical testing; mechanical testing should be carried out at actual clinical temperature; if fatigue testing is carried out, it is recommended to use clinically relevant solvents (such as PBS); If the shape memory properties of the device are utilized, it is recommended that shape memory testing be performed at clinical temperatures and service cycles, and that functional properties and device integrity be evaluated. 2. Stress calculation/strain analysis If a computational analysis is performed, an appropriate metal model should be used to correctly reflect the thermodynamic properties of the nitinol alloy. A material model may be selected by reference to ASTM F2516. The applicant shall verify the calculation model. If the device is subjected to a cyclic load test, the fatigue safety factor shall also be calculated. (III) Corrosion resistance test 1. Pitting Corrosion of nitinol alloys can lead to the release of nickel ions and affect the integrity of the device. The corrosion resistance depends on the manufacturing process and surface treatment. Pitting corrosion testing is recommended in accordance with ASTM F2129. 2. Release of nickel ion If Nitinol devices do not meet the accepted criteria for corrosion resistance or do not use a proven surface treatment process, a nickel ion release test should be considered. Refer to ASTM F3306 for the test method. 3. Galvanic corrosion If Nitinol devices are expected to be in contact with dissimilar metals, consideration should be given to performing a galvanic corrosion test, as recommended in ASTM F3044. (IV) Biocompatibility It is recommended to refer to ISO 10993 -1 for biocompatibility evaluation. If a nickel ion release test is performed, refer to ISO 10993 -17. (V) Label information It is recommended that the label clearly indicate that the device contains nitinol, suggesting that it may cause allergic reactions in patients,titanium seamless tube, especially in long-term or permanent implanted devices. III. References: [1] FDA. Technical Considerations for Non-Clinical Assessment of MedicalDevices Containing Nitinol - Guidance for Industry and Food and Drug Administration Staff. October 15, 2020 Tags: Medical Device FDA Registration, US Medical Device GMP Certification Return to Sohu to see more Responsible Editor:. yunchtitanium.com