Biomedical Engineering Reference
In-Depth Information
technicalities. For example, legal terms and their meanings are sometimes nonuniform
even within one regulatory system.
12.2.1 Medical Product Jurisdiction
When preparing a regulatory strategy for a product or technology, it is important to first
establish if the product is a device, a drug, or a biologic, and then to determine which
regulations apply. Two factors must be considered when making this distinction. First,
the manufacturer or supplier must clearly state and indicate the product's purpose and,
secondly, the exact way in which it is to be applied and/or used. From this, it is possible
to determine if the product is chemical/metabolism-altering (a drug) or physical in nature
(a device). For example, if an alginate wound dressing contains an antibacterial agent
whose sole purpose is to act as a barrier
between
the wound and the environment, it would
be classified as a device, since it is performing a physical function. On the other hand,
if the indication for use is to deliver the antibacterial agent (chemical)
onto
the wound
itself in order to treat an existing infection, then the alginate dressing is considered to be
a drug. In order to make this determination, one must carefully review the definition of
a medical device contained in the 1976 Medical Device Amendments of the Food, Drug,
and Cosmetic Act [9]:
An instrument, apparatus, implement, machine, contrivance, implant,
in vitro
reagent, or other similar or related article, including any component, part, or
accessory, which is:
1. Recognized in the official National Formulary, or the United States Phar-
macopeia (USP), or any supplement to them,
2. Intended for use in the diagnosis of disease or other conditions, or in
the cure, mitigation, treatment, or prevention of disease, in man or other
animals, or
3. Intended to affect the structure or any function of the body of man or
other animals, and which does not achieve its primary intended purposes
through chemical action within or on the body of man or other animals
and which is not dependent upon being metabolized for the achievement
of any of its principal intended purposes.
12.2.2 Types of Medical Devices
There is a wide variety of medical devices in use today. They range from room-sized
imaging systems that weigh several tons, to ophthalmic implants that are less than 2 mm
long and weigh only a few grams. Most
in vitro
diagnostic products (blood and urine
tests) are also regulated as medical devices. Table 12.1 below describes most devices
using two of their characteristics.
The left column shows the device function, and the right column shows its form.
For example, a lithotripter that uses sound waves to break up kidney stones would be
considered a durable therapeutic device; a pacemaker would be considered an implantable
therapeutic device, and so on. Issues such as reuse, shelf life, and device tracking impact
different types of devices in different ways.
