ABSTRACT
Almost 40% of the drugs currently marketed and close to 90% of the pipeline drugs exhibit poor water solubility and/or poor permeability, leading to an overall low bioavailability (Merisko-Liversidge and Liversidge 2008). Chemical modifi cation, crystal change, and size reduction have been investigated to improve the solubility of those Biopharmaceutics Classifi cation System (BCS) class II, III, and IV drugs. While these techniques have improved their
solubility, their absorption may still be low and their metabolism clearance high, resulting in a low therapeutic effect and potential serious side effects, as high dose must be administered. In situ delivery is known to minimize local and systemic side effects by employing a lower drug amount, to increase patient compliance and to improve the effi cacy of the treatment. Nanoparticle (NP) engineering technologies play an important role in the improvement of pulmonary and nasal drug delivery. These technologies encompass traditional techniques, such as milling and spray drying, as well as more recent techniques, such as cryogenic and supercritical processes. Using these techniques, scientists are able to produce engineered particles exhibiting specifi c physiochemical properties. Since pulmonary and nasal drug delivery requires particles with specifi c criteria and good aerosolization properties, NP technologies are great tools to produce inhaled and nasal drug formulations with optimum characteristics for lung and nose delivery. Developing such formulations will broaden the therapeutic options used to treat pulmonary, nasal, as well as certain systemic diseases. Pulmonary and nasal physiologies are correlated to particle deposition and absorption, and will be discussed in this chapter. NP technologies used in the pharmaceutical industry in addition to more innovative processes will be detailed. Finally the clinical considerations of pulmonary and nasal delivery of drug NPs will be discussed through several pertinent examples taken from the literature.
