Background: Treatment by the pulmonary route can be used for drugs that act locally in the lungs (e.g.
lung cancer) or non-invasive administration of drugs that act systemically (e.g. diabetes). The potential of using
drug delivery systems (DDS) formed from non-ionic surfactants or natural products for pulmonary drug delivery
Methods: The effectiveness of each DDS depends on it ability to not only entrap the relevant drug and alter its bio
distribution, but also its ability to withstand the physical stresses during nebulization and for the nebuliser to produce
aerosol particles with the size for deposition in the appropriate part of the lungs. Different methods must be
used to prepare nanoparticles (NP) using non-ionic surfactants, or biocompatible polymers from natural proteins or
sugars, and the aqueous solubility of the drug also influences the manufacture method.
Results: NP produced using non-ionic surfactants, proteins such as collagen, albumin or gluten, and polysaccharides such as chitosan,
hyaluronate, cellulose, carrageenans, alginate or starch has successfully delivered different types of drugs given by the pulmonary route.
Drug entrapment efficiency depends on the DDS constituents and the manufacture method used. Large scale manufacture of DDS from
natural products is technically challenging but changing from batch manufacture to continuous manufacturing processes has addressed
some of these issues, and inclusion of a spray drying step has been beneficial in some cases.
Conclusion: DDS for lung delivery can be produced using natural products but identifying a cost effective manufacture method may be
challenging and the impact of using different type of nebulisers on the physiochemical characteristics of the aerosolised formulation
should be an essential part of formulation development. This would ensure that some of the development work e.g. stability studies do
not have to be repeated as they will identify if a carrier to protect the DDS from the physical trauma caused by nebulisation.