Biomedical Engineering Reference
In-Depth Information
Medical devices are tools that are designed to facilitate or provide efficient
and safe delivery of drugs via various rotes of administration. Many medical
devices are simple in design such as those used for oral delivery, for instance
spoons, mouth drops, etc. However, some devices are highly sophisticated to
suit particular delivery applications such as those used in pulmonary, nasal and
transdermal delivery. The development of such devices may require
multidisciplinary team work involving scientists, engineers, chemists,
biologists and clinicians as well as experts in regulatory issues and marketing
in order to produce devices that are suitable for commercial use by patients.
It is also important to bear in mind that safe delivery is just as important as
efficient delivery. Medical devices may get contaminated by pathogenic
microorganisms or cross-contaminated as a result of delivering different drugs
using the same device. Some drug formulations may also interact with the
contacting surfaces of the devices, resulting in leaching of device materials
into the formulation or adsorption of one of the formulation components onto
the internal surfaces of the devices. Whilst leaching of device materials into
formulations might cause adverse biological effects or even toxicity to patient,
the consequence of adsorption of a formulation component onto internal
device surfaces depends on the type of the adsorbed material. If the adsorbed
material is a drug, a sub-therapeutic dose is expected to be delivered, and if the
adsorbed component is a preservative, microbial contamination may occur
before the expected expiry date of the formulation.
In this chapter, recent advances and technologies of drug delivery devices
are covered focusing particularly on sophisticated device technologies. The
rationale behind using each delivery route including advantages and
limitations has also been briefly explained.
2.
D
EVICES
U
SED IN
P
ARENTERAL
D
RUG
D
ELIVERY
Parenteral drug delivery is the delivery of medicines via any route of
administration except for the oral. However, traditionally, parenteral delivery
focuses on drug delivery applications that involve the use of needles for
injection. Parenteral solutions or dispersions are injected or infused directly
into blood vessels or surrounding tissues (e.g. muscular tissue). Parenteral
delivery may be appropriate when a rapid therapeutic response is required
since only few minutes are needed to produce an effect after parenteral
intravenous administration, which can be life-saving for patients in emergency
units. By contrast, hours may be needed to produce a therapeutic effect after
