For medical devices

Biomedical Applications. In the area of biomedical polymers and materials, two types of appHcations have been envisioned and explored. The first is the use of polyphosphazenes as bioinert materials for implantation in the body either as housing for medical devices or as stmctural materials for heart valves, artificial blood vessels, and catheters. A number of fluoroalkoxy-, aryloxy-, and arylamino-substituted polyphosphazenes have been tested by actual implantation ia rats and found to generate Httle tissue response (18). 

Another property pecuHar to SMAs is the abiUty under certain conditions to exhibit superelastic behavior, also given the name linear superelasticity. This is distinguished from the pseudoelastic behavior, SIM. Many of the martensitic alloys, when deformed well beyond the point where the initial single coalesced martensite has formed, exhibit a stress-induced martensite-to-martensite transformation. In this mode of deformation, strain recovery occurs through the release of stress, not by a temperature-induced phase change, and recoverable strains in excess of 15% have been observed. This behavior has been exploited for medical devices. 

The Quality System Regulation is introduced for medical devices, requiring developers of high-risk devices to apply design controls. 

The Global Harmonisation Task Force (GHTF) was conceived in 1992 to address similar issues for medical devices. It has a broader regional base than its pharmaceutical counterparts in that it includes representatives from Canada and Australia in its core group, in addition to those from the EU, US and Japan. In some ways, it also faces a stiffer challenge in that there is more divergence in the regulatory... 

Regulatory Strategy for Medical Devices in the US 177 NON INVASIVE DEVICES... 

FDA Design Control Guidance for Medical Device Manufacturers www.fda.gov. 

The Competent Authority to which the incident was originally reported usually takes on the role of monitoring and evaluating how the incident is dealt with. When all actions are complete, including any necessary Field Safety Correction Actions, the manufacturer must submit a final report to the Competent Authority. Under a safeguard clause. Competent Authorities may take unilateral action to remove a device from their market, if they believe that it poses an unacceptable health risk, but the Commission must be informed of such actions. In less-urgent situations, concerns may be referred to the Committee for Medical Devices for consideration. 

Only three countries, Tunisia, Uganda and Zimbabwe, do not issue a GMP certificate. The drug regulatory authorities in these three countries do conduct GMP inspections, but do not issue a specific document which indicates that a manufacturing plant has attained GMP standards. The MCAZ does, however, provide a GMP certificate at the manufacturer s request to facilitate international registration and export of products. In Malaysia, various types of certificates are issued GMP certificates Certificate of Pharmaceutical Product for export and Certificate of Free Sale for medical devices and cosmetic products. Cyprus has no clear criteria for issuing a GMP certificate instead. 

At the FDA, a major effort is under way to streamline the process by which medical devices are reviewed and evaluated. The FDA has made significant progress in its quest to provide review of medical devices in a more timely manner. In fact, the agency has completely cleared its backlog of 510(k) and PM A applications for medical devices and is now turning its attention to quicker, more efficient reviews... 

Common biodegradable polymers for medical devices are constructed from synthetic linear aliphatic polyesters. One material commonly used for internal sutures is poly(glycolic acid) (PGA). PGA is synthesized from the dimer of glycolic acid (Fig. 13.1.l). 1... 

The ultimate product of the pharmaceutical toxicologist will thus generally be the toxicology summaries of the IND and NDA (or PLA). For medical devices, the equivalents are the IDE and Product Development Notification (PDN). Data required to support each of these documents is specified in a series of guidelines, as will be discussed below. 

Both CDER and CDRH will administer and, as appropriate, enforce the following activities for medical devices assigned to their respective Centers (References to Sections are the provisions of the Act) ... 

Similar exercises must be performed to identify synthetic nanocomponents. Considerations include suitability for the proposed environment, synthesis and handling properties, polydispersity, structural / chemical properties, as well as amenability to assembly into higher order structures. For medical devices, tolerability and safety of the structural materials is also an issue. Current materials technology offers powerful, but limited capacity to engineer an off the shelf approach to nanostructures. 

Titanium alloys generally show a combination of strength and biocompatibility which makes them suitable for medical devices (prosthesis, surgical instruments). The high strength Ti-6Al-7Nb alloy has several orthodontic applications. Only a limited number of alloys have the necessary combinations of properties needed for successful use in the human body. Titanium and its alloys, stainless steels and cobalt-chromium alloys are the workhorse alloys in the medical device industry. 

A manufacturer must apply an appropriate conformity assessment procedure to their device in order to ensure that it complies with the essential requirements, after which they must certify this fact by completing a declaration of conformity. There is usually a choice of conformity assessment procedures open to a manufacturer, depending on a risk-based classification of the class into which the device falls. The two main approaches to conformity assessment are based either on an approved total quality management system audited to ISO 9000 series standard, as customised for medical devices with EN 46 000 series standard, or individual product assessment. 

Requirements for medical devices connected to, or equipped with, an energy source... 

One court has interpreted the FD C Act as not authorising FDA to require restitution by a manufacturer to purchasers of a product that has been found to violate the FD C Act, but a more recent court decision has upheld restitution. The Medical Device Amendments of 1976 explicitly provide such authority for medical devices. ... 

There are multiple applications of fluoridated bioceramics, essentially as bone and tooth substitutes (Table 1), involving bulk ceramics, glasses, composite materials and coatings for medical devices and surface treatments. In some cases, fluoride ions can leach out of the material inducing a direct biological effect in a soluble form. However, considering the affinity of fluoride ions for apatite... 

Hill, D., Design Engineering of Biomaterials for Medical Devices, John Wiley Sons, New York, 1998. 

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