ABSTRACT
Drug Delivery ........................................................................................................... 491 21.8 Future Directions .................................................................................................................. 491 21.9 Conclusions ........................................................................................................................... 492 Acknowledgments .......................................................................................................................... 492 Abbreviations ................................................................................................................................. 492 References ...................................................................................................................................... 493
An aerosol is a mixed phase colloidal system that arises when solid particles or liquid droplets are dispersed in a gas. The colloidal particle size range is between 1.0 nm and 1.0 µm; however, some particles, for example, bers, are larger than this range. Colloid technology is rapidly becoming more rational in terms of applications in different areas such as modern food technology, pharmaceutical and cosmetic preparations, and paints. Colloidal medicinal aerosols are used to improve human health, and aerosol therapy by inhalation has been used for many years. A wide variety of medicinal colloids are administered to the lungs by oral inhalation for the treatment of diverse disease states, especially for the management of asthma and obstructive airway diseases. Direct delivery of drugs into the pulmonary regions of the lung enables lower doses with equivalent therapeutic action compared to oral or parenteral routes because of the large surface area (~100 m2) of the lungs. The advantages of aerosol formulations over other dosage forms (i.e., parenteral and other liquid dosage forms) are that they are noninvasive, easy to use, less expensive, painless, and user friendly. The inhaled route allows the delivery of small doses of drug directly to the alveoli, attaining a high concentration of drug in the local area and minimizing systemic side effects. This results in a high therapeutic ratio of drugs compared with that of systemic delivery administered by either oral or parenteral routes. This chapter demonstrates aerosol delivery of various medicinal colloids for the optimal management of various disease states.
