Biomedical Engineering Reference
In-Depth Information
(FD&C)
1
Act, the term medical device means an instrument, apparatus, implement,
machine, contrivance, implant,
in vitro
reagent, or other similar or related item, intended
for use in the diagnosis of disease or other conditions, or in the cure, mitigation, treat-
ment, or prevention of disease, or intended to affect the structure or any function of the
body, and which does not achieve its primary intended purposes through chemical action
within, or on, the body.
Biocompatibility is a factor that must be considered for those medical devices which
make contact with the body and adds even more complexity to the already challenging
issues of medical devices. In general, a medical device consists of a variety of materials
and is one of the factors that play an important role in the question of whether or not
a medical device meets the requirements for human use (in other words whether it is
'biocompatible'). To consider the biocompatibility aspects, however, one must not only
consider the applied materials, but the complete medical device as a whole and its intended
use in the human body. The biocompatibility of a medical device depends on many factors,
such as the time that it is exposed to the human body and the location in the body where
it is applied or implanted. Also, the effect of a product and its materials on humans
may vary, depending on its application, such as if it is noninvasive or invasive, and the
frequency and duration with which it is used. Contact time and location in the human body
varies from external to internal applications. Biocompatibility of these devices depends on
the application within the human body. For instance, a material may be biocompatible for
external application, but not internal use. Apart from the materials and its intended use, the
biocompatibility of a medical device is also influenced by its production process, during
which the quality of materials may decline and, as a consequence, the applied materials
must be judged in their final state. Degradation can be caused by heat, temperature, or
contact with other materials. Cleaning, packaging, and sterilization may alter the quality
of materials. Therefore, the complete production process has to be taken into account in
order to establish the biocompatibility of a medical device.
Society has benefited tremendously from the development and utilization of mechan-
ical devices which are implanted inside the body to replace bones and joints, increase
blood flow, and even measure blood chemistry. To further enhance the performance of
these devices, the application of thin films to external surfaces is an ongoing research
and development interest in many companies. Engineers have the choice of a variety
of technologies to apply liquid coatings to these often complex surfaces, ranging from
vacuum technology to direct liquid application. Although most of the materials used in
medical devices have been investigated at the bulk scale for their biocompatibility, the
toxicity and hemocompatibility of certain materials is still to be determined and more rig-
orous research studies need to be undertaken. Thin films are much more convenient and
preferred to coatings. As the properties of thin films depend heavily on their deposition
process, further research needs to be carried out on the behavior of thin films compared to
1
The United States Federal Food, Drug, and Cosmetic Act (abbreviated as FFDCA, FDCA, or FD&C), is a set
of laws passed by Congress in 1938 giving authority to the US Food and Drug Administration (FDA) to oversee
the safety of food, drugs, and cosmetics. A principal author of this law was Royal S. Copeland, a three-term
US Senator from New York [1]. In 1968, the Electronic Product Radiation Control Provisions were added to the
FD&C. Also in that year the FDA formed the Drug Efficacy Study Implementation (DESI) to incorporate into
FD&C regulations the recommendations from a National Academy of Sciences investigation of the effectiveness
of previously marketed drugs [2]. The act has been amended many times, most recently to add requirements about
bioterrorism preparations.
