diseases, the determinants of what are now called idiosyncratic drug effects will
become apparent. The application of statistical algorithms to gene expression data
is a relatively recent development (Wen et al. 1998 ). Further development of these
bioinformatic techniques will greatly increase the value and application of these
data sets. Increased understanding of mechanisms underlying susceptibility in one
species may be directly translated to others of special veterinary interest. Deficien-
cies in biotransformation or drug transport due to lack of an enzyme or drug
transporter, as for example the sensitivity of Collies and related canine breeds
due to the absence of the MDR-1 gene coding forp-glycoprotein transporter
(Mealey 2004 ), will be better defined and screened.
Genomics, proteomics, and metabolomics are being integrated into many
approaches to screening for toxicological effects (Riviere 2006 ). This can be
expected to reduce the drop-out rate of lead drug candidates. As experience inter-
preting these systems is gained, integrated databanks will be generated which allow
more accurate SAR studies to be conducted. As these relationships are validated,
they will enable the development of more robust in silico pharmacology and
toxicology screens. What was previously described as exercises in data-mining is
now the field of analytics, for which graduate training programmes for specialists in
analysing such integrated databases are now in place.
10 Potential Impact on Veterinary Medicine
All of the approaches and techniques described in this chapter streamline and
optimise the drug discovery process and are potentially applicable to all therapeutic
classes. It is unlikely that novel therapeutic classes of drugs replacing existing
compounds will be developed, for example oligonucleotides or exotic material
nanodrug devices, as replacements for organically synthesised drugs. Rather,
there will be a refinement of drugs based on more selective activity and with
reduced potential for untoward side-effects applying high-throughput analysis to
combinatorial chemistry libraries, or alternatively QSAR to design drugs with
highly selective properties. Components of these increasingly efficient screens
will include separate assays for ADME, efficacy and toxicity, as well as resistance
for antimicrobial and anthelmintic drug classes to ensure that viable drug candi-
dates emerge.
Drugs formulated with specific targeting moieties will become more common.
The controlled delivery of drugs to target tissues will be enhanced using techno-
logies already in the process of being commercialised. Examples are the use of
advanced polymer chemistry, nanodrug formulations, microneedles and/or electri-
cally-assisted delivery techniques. Species-specific drug delivery devices will
become more common. The benefit will be to render administering drugs to animals
easier and less frequent. Cats are an obvious target species for many of these
approaches due to the difficulties owners have in administering oral medications
on a daily basis to this species.
206 J.E. Riviere