Interventional devices for neurovasculature, how to choose a vascular model for simulating use in in vitro studies
The model simulating the anatomy of neurovasculature should reflect the anatomical characteristics of neurovasculature in different clinical scenarios, considering factors such as vessel diameter, curvature radius, curvature shape, number of bends, vessel length, friction coefficient of the inner vessel surface, and model material. Specifically, the model simulating the anatomy of neurovasculature should start from the proximal puncture intervention position (such as the radial artery, femoral artery) and should include at least the cervical internal carotid artery siphon segment, two 180-degree bends, and two 360-degree bends. Application materials should describe the model simulating the anatomy of neurovasculature, providing images and diagrams of the model, specifying the material of the model, and key dimensions (such as length, vessel diameter, curvature radius, etc.). It is also recommended to provide supporting data for the selection of the neurovasculature anatomy model, such as image information and relevant literature on anatomical data for the target population.
Factors to consider when conducting precision studies on qualitative in vitro diagnostic reagents based on the principle of immunochromatography
When conducting precision studies on qualitative in vitro diagnostic reagents based on immunochromatography principles such as colloidal gold method, the following factors should be considered in the experimental design: different sample concentrations, reagent batches, testing rounds, time, operators, locations, and other influencing factors. In the test results, it is essential to not only provide positive and negative results but also submit data compared to a standard color card (e.g., L1, L2, L3...) and perform consistency analysis on the color intensity.
How to evaluate the desensitizing effect of dental desensitizers
Dental desensitizers fall under the category of desensitizer products in the "Medical Device Classification Catalog" (2017 Edition) as 17-10-03 desensitizer products. For physically occlusive dental desensitizer products, the desensitizing effect can be evaluated using studies on dentinal tubule sealing effects. Currently, there are two main in vitro testing methods to assess their sealing effects. The first method is dentin permeability testing, which measures the permeability values of dentin slices before and after experimental sample treatment to determine the relative permeability values of the dentin slices after treatment. The second method is scanning electron microscopy observation, where the number of open dentinal tubules in dentin slices after experimental sample treatment is observed and recorded, along with the number of open dentinal tubules in the control group. The dentinal tubule occlusion rate is calculated to evaluate the desensitizing effect. For desensitizers that require long-term use, the frequency of application should also be considered. The acceptance limits for the relative permeability values of dentin slices or the dentinal tubule occlusion rate should be explained based on their determination basis, evaluated for acceptability, and whether they can achieve the expected clinical results. For dentin desensitizing materials that react with collagen in the dentinal tubule fluid in living teeth (such as glutaraldehyde-based materials) and non-occlusive dentin desensitizing materials (such as potassium ion-based materials that reduce dentin nerve sensitivity), other methods should be considered to demonstrate the desensitizing effect of the product based on how the product functions.
How to choose a vascular model for simulating the use of interventional devices in coronary arteries
When selecting a model to simulate the anatomy of coronary arteries for interventional devices, consider the following factors to reflect the anatomical characteristics of coronary arteries in different clinical scenarios: vessel diameter, curvature radius, curvature shape, number of bends, vessel length, friction coefficient of the inner vessel surface, and the material of the model. Reference can be made to ASTM F2394 standard for guidance. The application materials should describe the model simulating the anatomy of coronary arteries, including providing images and diagrams of the model, specifying the material of the model, and key dimensions (such as length, vessel diameter, curvature radius, etc.). It is also recommended to provide supporting data for the selection of the coronary artery vascular anatomy model, such as image information and anatomical data related literature for the target population.
How to conduct research on the disinfection effectiveness and compatibility of blood dialysis equipment using citric acid disinfectant
Provide the confirmation basis for the disinfection program of blood dialysis equipment under the most unfavorable conditions, including the lowest concentration of the main effective ingredients, the shortest contact time, and the lowest operating temperature. At least include the log reduction value of ≥3.00 for killing Bacillus subtilis var. niger spores during simulated on-site testing. Provide research data on the impact of the disinfectant on the performance of blood dialysis equipment under clinical conditions (contact time, operating temperature, etc.), including: ① the mutual influence of the disinfectant with various components and accessories on the blood dialysis machine (such as temperature or conductivity electrodes, flow monitoring devices, etc., whether there will be an impact). ② Corrosiveness of dialysis equipment components and pipelines after long-term use. In addition, provide research basis and reasonable explanations for the number of uses.
In the case of a change registration for adding applicable models for in vitro diagnostic reagents, if there is a change in the amount of reagent or sample added on the new model, is it necessary to submit clinical evaluation data?
If there are no changes in the composition, production process, and intended use of the in vitro diagnostic reagents, and the application is to add applicable models, and if there are no changes in the amount of reagent and sample added on the new model or if there are changes but the proportion of reagent and sample in the final reaction system remains the same, then generally there is no need to submit relevant clinical evaluation data. However, if there is a change in the proportion of reagent and sample added in the final reaction system on the new model, then corresponding clinical evaluation data should be submitted for this change during the registration modification.
How to evaluate the bonding effectiveness of dental adhesives
The bonding process in the adhesive interface involves complex physical and chemical processes. The bonding effectiveness of dental adhesives can generally be evaluated and validated through various methods such as bond strength, bond durability, measurement of bonding interface gaps with dental tissue, and studies on microleakage. When conducting the above studies, it is important to consider the bonding interface of the adhesive system, taking into account the intended use of the product, actual application scenarios, and clinical application techniques. Samples should be prepared according to the instructions for the evaluation of the bonding performance and durability of the adhesive between different dental hard tissues (enamel, dentin) and different materials (metal, resin, ceramics, etc.) used as filling materials/repairs, as well as studies on microleakage and gap measurements after filling with different materials. For evaluating the bonding effectiveness, comparisons can be made under the same test conditions with similar products on the market to discuss the acceptability of the results.
For conventional ultra-high molecular weight polyethylene orthopedic implant products, can the accelerated aging tests in YY/T 0772.3 and the accelerated aging tests in product stability studies be used interchangeably?
For conventional ultra-high molecular weight polyethylene orthopedic implant products, applicants should evaluate the stability of the material (such as oxidation index and mechanical properties before and after aging) and morphology according to the methods in standards YY/T 0772.3, YY/T 0772.4, and YY/T 0772.5. These methods do not simulate the relationship between test conditions and real-time storage aging of the product, so they cannot be considered equivalent to product stability studies. In the accelerated aging tests of product stability studies, the test conditions assume that the chemical reactions involved in material degradation follow the Arrhenius function, allowing for the inference of material aging under normal storage conditions. Therefore, the stability of the product (including shelf life) should be studied following the "Guiding Principles for Stability Studies of Passive Implantable Medical Devices," and real-time stability or accelerated stability study data should be submitted.
How to conduct a biocompatibility evaluation for single-use abdominal puncture devices
To conduct a biocompatibility evaluation for a single-use abdominal puncture device, follow the evaluation requirements specified in the GB/T 16886 series of standards. This product is an external access device that comes into contact with human tissue for a short duration not exceeding 24 hours. The evaluation should include at least the following items: cytotoxicity, sensitization reactions, and intradermal reactions.
In the section "Main Components" of the instructions for in vitro diagnostic reagents, under the category of "Items Needed but Not Provided," how should the registration number/filing number/product number be filled in?
In the "Items Needed but Not Provided" section of the in vitro diagnostic reagents instructions, you should list the names of reagents required for testing but not included in the test kit. If the reagent has obtained a registration number/filing number, you should indicate "Registration Number/Filing Number and Product Number." If the reagent is currently in the registration/filing stage, you should indicate "Product Number and Registration Number: (blank)/Filing Number: (blank)," and the specific document numbers should be added by the registrant after the completion of registration/filing.