Biological evaluation of medical devices - Application of the threshold of toxicological concern (TTC) for assessing biocompatibility of medical device constituents

2019 ◽  
2021 ◽  
Vol 5 (4) ◽  
pp. 228-237
Author(s):  
Oleksandra Dmytrenko ◽  
Maryna Arkhypova ◽  
Darya Starosyla ◽  
Svitlana Rybalko ◽  
Michael Gevorkyan ◽  
...  

Background. Programs of preclinical safety studies of the health care products depend on the regulatory status of the investigated products. The classification of such products, in particular suppositories for rectal and vaginal use, is a critical step of developing tactics for their biological evaluation. Adaptation of biological evaluation methods for the medical devices based on the combination of biologically active substances, as well as evaluation of the results of such studies is urgent task of biomedicine. Objective. To substantiate the regulatory status and to carry out a biological evaluation of medical devices in the form of vaginal suppositories based on octenidine dihydrochloride ("Prodexyn") and in the form of rectal suppositories based on Saw palmetto, Levisticum officinale and Calendula officinalis extracts ("Pravenor"). Methods. Biological evaluation was conducted according to the requirements of ISO 10993 standards using in vitro and in vivo biological test systems (cytotoxicity in cell culture and the MTT test, sensitizing and irritating effect in guinea pigs). Results. The cytotoxicity (СС50) of the medical device "Prodexyn" extract in Vero cell culture was 8.35 μg/ml calculated as octenidine dihydrochloride and 416.65 μg/ml calculated as dexpanthenol. "Pravenor" medical device was found to be non-toxic in Vero cell culture. According to the results of MMT assay CC50 for octenidine dihydrochloride was 1.67 μg/ml, and 83.33 μg/ml – for dexpanthenol. CC50 indicators calculated for the different active ingredients of the medical device "Pravenor" were the following: 50 mg/ml for the dwarf palm berries extract (Saw palmetto), 16.67 mg/ml for the lovage roots extract (Levisticum officinale), and 16.67 mg/ml for the calendula flowers extract (Calendula officinalis). No sensitizing or skin irritating effects were observed in guinea pigs. Conclusions. Biological evaluation of medical devices in the form of rectal suppositories "Pravenor" and vaginal suppositories "Prodexyn" performed using in vitro and in vivo biological systems. It was demonstrated an acceptable level of safety of the products. The MTT test was 5 times more sensitive than the Vero cell culture method in determination of cytotoxicity.


2018 ◽  
Author(s):  
Anna Reifschneider

The U.S. Food and Drug Administration ("FDA") regulates all medical devices in the United States. As part of its regulatory duties, the FDA provides guidance documents on various regulatory topics as mandated by the U.S. code of federal regulations. Since 2015, the FDA has begun to issue many substantial revisions to their guidance documents that directly affects the regulatory framework on biocompatibility, reprocessing, and sterilization.These regulatory issues are of paramount importance for many companies because of the potential high costs involved in changing their internal design, controls, manufacturing, and quality systems. This master’s thesis examines the various changes made by the FDA in recent years on the inter-related topics of biocompatibility, reprocessing, and sterilization. Some of the major changes by the FDA involve an increase in the importance of chemical characterization, a reduction in the use of animal testing, a requirement for an independent validation of the user instructions for reusable devices, and increased usability testing.The principal reasons for these major policy changes by the FDA are shown to be the major device scandals that recently involved duodenoscopes, metal-on-metal hip implants, and vaginal surgical mesh implants. Along with several other regulatory failures that made national news headlines in the United States, the FDA began to revise several of their previous medical device guidances. The information from this master’s thesis can be used by medical device developers and manufacturers, especially when they are located outside of the United States and lack sufficient regulatory affairs resources to provide independent advice and recommendations on these important FDA changes. A thorough analysis is made of the new FDA guidances to clarify several potentially difficult questions for medical device manufacturers, specifically the following: (1) "Use of International Standard ISO 10993-1, ‘Biological evaluation of medical devices - Part 1: Evaluation and testing within a risk management process", (2) "Reprocessing Medical Devices in Health Care Settings: Validation Methods and Labeling", and (3) "Submission and Review of Sterility Information in Premarket Notification (510(k)) Submissions for Devices Labeled as Sterile". This master’s thesis is intended to provide not only an overview of the current FDA requirements, but to function as a guide for both researchers and engineers to improve their medical device design and development process.


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