required for the production of such devices is miniaturisation and better definition
of the demands of the clinical marketplace. Should the occurrence of drug-induced
microbiological resistance become so widespread as to limit the use of antimicro-
bial drugs in the face of widespread infectious disease, such tailor-made approaches
might become necessary and thus economically feasible. If such systems were also
coupled to microcomputers containing pharmacokinetic algorithms which are
already readily available, minimum inhibitory concentrations (MIC) could be
determined and drug dosage regimens directly calculated. For those drugs with
narrow therapeutic indices, a drug concentration analysis could be performed to
dictate adjustment of dosage regimens if needed. Such developments are within our
ability to accomplish. However, the absolute need and market requirements are not
yet in place to foster their development.
Particularly valuable and innovative would be the use of implantable drug
delivery devices containing both micro TAS and MEMS components within a
single device. An obvious application would be for insulin delivery in conjunction
with an on-board glucose sensor, or cardiovascular arrhythmia control via a heart
rate monitor and controlled drug release device. In large animal medicine, applica-
tions could be developed for reproductive synchronisation, for automatic detection
of specific microbial resistance determinants and for controlled drug release, based
on an endogenous triggering signal. Finally, it is possible also to envisage the
development of implantable endocrine organs that would radically alter the man-
agement of chronic diseases.
At the present time the development of units of this kind for veterinary patients
would not be cost-effective. However, in the foreseeable future, manufacturing
costs will be reduced and even now their manufacture is within the capability of
most biomedical engineering graduate students. The major unknown challenge is if
and how regulatory systems will adapt to the assessment of subject-individualised
devices. Independent clinical chemistry or drug analysis units could be approved
under current regulations, but it is the integration of these with drug delivery on an
individual animal basis for which the regulatory path is unclear. Similarly, approving
individual animal drug dosages based on an automated feedback system will
require the development of new regulatory guidelines.
6 Nanotechnology
Nanotechnology is another transforming technology that has the potential to alter
dramatically drug therapy. It may be defined as manufactured materials that are
< 100 nm across one dimension and possess unique physical properties due to this
small size (National Research Council 2006 , 2009 ; Leduc et al. 2007 ; Booker and
Boysen 2005 ). Potential applications range from use as drug carriers to truly
futuristic possibilities, including nanofactories, artificial ribosomes and wholly
manufactured cells. This account will focus on shorter-term, more realistic deve-
lopments that could lead to novel products within the next two decades.
New Technologies for Application to Veterinary Therapeutics 201