ABSTRACT
An aerosol is a small particle or droplet suspended in air. There are two main areas in which aerosols are of interest in pharmaceutics; these are the counting and analysis of airborne particle contamination, in the validation and quality control of clean rooms and sterile facilities, and in the study of particle and droplet sprays. Although these sprays have a wide variety of uses, such as application of liquids to surfaces, their most highly developed form is the metered dose inhaler, a device for delivering a small amount of aerosolized drug to the pulmonary system. Much of the technology discussed in this chapter has been applied to the engineering of these devices to optimize the delivery of drugs by inhalation. Of course, these methods have a much wider sphere of application outside pharmaceutics; much of the early interest in aerosols was derived from attempts to explain atmospheric diffraction phenomena, which are now fairly well understood, (see for example Craig Bohren’s recent volume ‘Clouds in a glass of beer’ (Bohren 1987) for a popular exposition of this area). Other applications include studies of dust explosions in mines, industrial hygiene and pollution, and the application of paints and coatings.
