Inhaled drugs for small animals are, however, used to treat local conditions
including canine bronchitis, kennel cough and feline asthma. The advantages are
high local concentrations and reduced systemic side-effects. Rozanski et al. ( 2007 )
have outlined the major challenges for aerosol delivery to small animals. Particle
size diameter is critical in order to reach different parts of the lung and this is
governed in part by the type of inhaler as well as whether the particle formulation is
in the format of a dry powder, liquid droplet or spray-dried. Device research for
pulmonary delivery to cats and dogs involves species-specific metered dose nebu-
lisers for usually uncooperative patients, who will not take or hold a deep breath on
request. Improved devices including Aerokat 1 and Aerodawg 1 (Trudell Medical
International) have become available recently and, at least in cats, owners seem
only too happy to demonstrate their simplicity of use in videos available on
YouTube 1 (www.youtube.com). Drugs that have been administered by the pul-
monary route include fluoroquinolones, slow-release theophylline,b 2 -adrenorecep-
tor agonists (albuterol), muscarinic antagonists (ipratropium) and anaesthetics
(propofol) (Rozanski et al. 2007 ). Notable successes in equine pulmonary therapy
involve use of specialised masks or hand-held inhalers to deliver aerosols such as
salmeterol and pirbuterol for recurrent airway obstruction, colloquially known as
“heaves” (Henrikson and Rush 2001 ; Derksen et al. 1996 ). Application of drugs,
vaccines, and other biologicals in aquaculture for delivery via gills is an important
topic which has been reviewed elsewhere (Shao 2001 ).
Nasal drug delivery in animals has had more restricted application compared to
the human sector, limited to either species-specific mucosal vaccination or as
veterinary medicine models for human nasal vaccination and/or drug delivery.
Early research in animals suggested that nasal administration of benzodiazepenes
to Beagles induced a faster onset of sleep than administration by the oral route
(Lui et al. 1991 ), and the concept of nose-to-brain delivery of central nervous
system (CNS)-active drugs is currently much in vogue in human medicine (Wu
et al. 2008 ). Sheep have potential as a screening system for nasal drug delivery to
man as relative surface areas for absorption are similar. Sheep have also been used
to examine the absorption-promoting effects of the mucoadhesive polymer, chit-
osan, on nasal delivery of salmon calcitonin (Hinchcliffe et al. 2005 ). For nasal
vaccine delivery, the rationale is to induce local mucosal immunity, mediated in
part by secretory IgA against pathogens invading surface epithelium. To this end,
live attenuated kennel cough nasal vaccines againstBordetella bronchiseptica
have been marketed, including Nobivac BbTM(Intervet/Schering-Plough Animal
Health) for cats and Naramune-2TM (Boehringer Ingelheim) for dogs. At a
research level, a range of veterinary species are being investigated for nasal
vaccination against specific pathogens using a variety of novel microparticle
encapsulation technologies and adjuvants (Table 3 ). Nanoparticulate vaccine
delivery systems delivered by ballistic devices are also being extensively tested
in veterinary species and in wildlife (Scheerlinck and Greenwood 2006 ). Airway
delivery of protective vaccines remains a subject of current interest and potential
targets include herds, flocks of poultry and wild animals (Ploegaert et al. 2007 ;
Fourie et al. 2008 ).
Drug Delivery Systems in Domestic Animal Species 87