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Global
Trends in Medical Plastics Technology and Applications
Devices are also used in the areas of
orthopedic treatment such as artificial spinal discs or
articulating joints, within the area of dental medicine as
artificial crowns, fillings and adhesives, plastic
surgery, ophthalmology etc.
A growing area of the use of plastics
is in the field of combination devices, here the plastic
is part of the device as an excipient or carrier for drug
delivery (Figure 4). Drug delivery occurs mainly through
diffusion of the drug though the polymer matrix. There is
also development in the use of resorbable plastics,
plastics that degrade over time in the body and this
degradation allows the drug to escape from the device and
enter the body. Since drugs can be both hydrophilic and
hydrophobic, the ability of the polymer matrix to
accommodate the differing polarity of the drug is an
important aspect and therefore the design of plastics to
act as effective excipients is an
area of considerable research.
Another area where plastics are
increasingly being used is in the coating of devices that
act as continuous glucose monitoring (CGM) devices in the
monitoring and treatment of diabetic conditions (Figure
5). CGM sensors rely on the coating to be permeable to the
right substances so that it can accurately sense the level
of glucose in the blood. The area of selective
permeability is an area of important research.
 .
Figure 4: A drug delivery device
where the drug infused in a polyurethane is a
contraceptive
Figure 5: A continuous glucose
monitoring (CGM) sensor coated with a polymeric film
Operations and
Manufacturing of Plastic Components for Medical Devices
The manufacturing
operation for the manufacturing of a plastic component of
a medical device can be depicted as in Figure 4.
Figure6: Depiction of
the steps in the manufacturing process of a component for
medical devices
Plastic: The
plastic can be chosen as a commodity plastic or it can be
custom made. The choice of the plastic will be decided by
the application of the device the component is intended
for. In many instances, the quantity of plastic required
for a medical device is small, often measured in grams.
Thus, it is entirely feasible that a small batch of
specialized plastic can be synthesized for a particular
device. Of course, knowledge of the chemistry of the
plastic, its reaction kinetics and certain chemical
engineering fundamentals are required. However, as the
quantities required are small, it is entirely feasible to
set up manufacturing operations. This is especially true
where certain special materials such as biodegradable
formulations are involved, device applications may require
specific behavior from its components such as degradation
characteristics and drug elution.
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