ABSTRACT
There is tremendous excitement today about nanotechnology. The nanometer size range spans the diameters of individual soluble protein molecules (2-16 nm; https://www.ivdtech nology.com/article/measuring-hydrodynamic-radius-nanoparticle-formulations), to the thickness of the type 1 alveolar epithelial cells of the lungs (100 nm) (Patton 1996), to the diameters of viruses (30-300+ nm) and bacteria (250-3000 nm) (https://www.ionizers.org / Sizes-of-Bacteria.html). Human cells are amazing assemblages of exquisite nanostructures that make up the living system (bilayer membranes, ribosomes, endosomes, mitochondria, chloroplasts, Golgi apparatus, chromosomes, tight junctions, etc.). Biochemists, cell biologists, and drug developers have been examining, isolating, characterizing, and making some types of nano-sized structures for nearly a hundred years (subcellular organelles, micelles, crystals, colloids, liposomes, etc.). Why has this particular size range become so exciting lately? It is because we are learning how to precisely make complex
CONTENTS
13.1 Initial Comments ............................................................................................................... 211 13.2 Optimum Aerosol Particle Size for Efcient Lung Deposition ................................... 212 13.3 Practical Issues of Inhaled Mass and Irritation ............................................................. 214 13.4 Inhaler Devices................................................................................................................... 215
13.4.1 Nebulizers ............................................................................................................... 215 13.4.2 Metered Dose Inhalers (MDIs) ............................................................................. 216 13.4.3 Dry Powder Inhalers ............................................................................................. 217
13.4.3.1 Two Major Challenges with Dry Powders: Agglomeration and Moisture Protection ................................................................................ 217
13.4.4 SUPRAER Technology .......................................................................................... 218 13.5 Events at the Air-Blood Tissue Barrier: Regional Deposition and Clearance of
Nanoparticles ..................................................................................................................... 218 13.6 Events at the Air-Blood Tissue Barrier: Systemic Absorption and Metabolism
of Nanomolecules (i.e., Proteins) ...................................................................................... 219 13.6.1 Events at the Air-Blood Tissue Barrier: Features of Systemic Pulmonary
Absorption and Processing of Proteins .............................................................. 219 13.7 Summary ............................................................................................................................. 221 References ..................................................................................................................................... 221
nanostructures and how to manipulate their properties, and discovering their interesting and powerful applications in medicine and in all elds of science. It is the size range just above the size of a small molecule (the water molecule has a diameter of ~0.3 nm), partly visible by electron microscopy and at an order level in which an almost innite number of complex, multifunctional physical chemical structures relevant to humans can be designed.
