Inflammatory diseases that occur in the pharynx and involving both the adenoids and tonsils are important
not only for being very frequent, but also because they often require minor surgery for their resolution. These
structures have immunological functions leading to production of antibodies, and work in the local immunity
of the pharynx and protection of the entire body. The most common etiologic agent of sore throats is
Streptococcus pyogenes, an important pathogen of the beta-hemolytic group A which causes streptococcal
pharyngitis. The emergence of antibiotic-resistant bacterial strains and the poor penetration of chemical
antibiotics in bacterial biofilms raise the need for safe and effective options of antimicrobial treatment. The
application of bacteriophages (or cocktails therefrom) has been proposed as an alternative (or complement)
to conventional chemical antibiotics, allowing the release of natural predators of bacteria directly on these
biofilms. The major advantage of bacteriophage-based antibiotherapy relative to its conventional chemical
counterpart is that bacteriophages replicate at the site of infection, being available in abundance where they
are needed the most. When compared with chemical antibiotics, bacteriophages have other important
advantages: (i) strong tissue permeability, (ii) bacteriophage concentration remains high at the focus of
infection, continuously increasing with bacterial (host) presence, (iii) elimination of the focus of infection
occurs only after eradication of the host bacterium, (iv) bacteriophages are fully compatible with antibiotics
and may act synergistically, (v) they are specific against the target bacteria, (vi) have a superior ability to
penetrate bacterial biofilms, inducing production of enzymes that hydrolyze the biofilm polymeric matrix, (vii)
although bacteria can develop resistance to bacteriophages, isolation of new lytic bacteriophages is much
simpler and cheaper than developing a new chemical antibiotic. In this research effort, development of a
biotechnological process for the inhalational administration of a bacteriophage cocktail (endotoxin free) was
pursued, using strategies of nanoencapsulation within lipid nanovesicles (as forms of protection for the
bacteriophage against the immune system) to treat infectious pathologies such as pharyngo-tonsillitis
caused by Streptococcus pyogenes. This method of targeting may have a high potential for the treatment of
bacterial infections of the respiratory tract, since inhalation therapy is considered to be favorable to certain
respiratory infections because the aerosol is delivered directly at the site of infection, accelerating the action
of bacterial predators. Additionally, a smaller amount of bioactive substance is needed, thus preventing or
reducing possible side effects. As a proof of concept for the nanoencapsulation strategy, and since there is
not yet available a strictly lytic bacteriophage cocktail for Streptococcus pyogenes, a well-defined and
characterized bacteriophage was utilized, viz. bacteriophage T4. Water-in-oil-in-water (W/O/W) multiple
emulsions are nanosystems in which dispersions of small water droplets within larger oil droplets are
themselves dispersed in a continuous aqueous phase. Due to their compartimentalized internal structure,
multiple emulsions present important advantages over simple O/W emulsions for encapsulation of
biomolecules, such as the ability to carry both polar and non-polar molecules, and a better control over
releasing of therapeutic molecules. T4 bacteriophage was entrapped within W/O/W multiple nanoemulsions,
aiming at mimicking the multifunctional design of biology, optimized with several lipid matrices, poloxamers
and stabilizing layer compositions. Physicochemical characterization of the optimized bacteriophageencasing
nanovesicle formulations encompassed determination of particle size, size distribution and particle
charge, via Zeta potential analysis, surface morphology via CRYO-SEM, and thermal analysis via DSC