Approximately 20 million Americans have asthma, nine million of them children under 18. The prevalence of asthma has increased 75 percent from 1980-1994, with rates for children under 5 increasing by more than 160 percent during the same period. Approximately 5,000 people a year die from asthma, with total health care costs totaling $11.5 billion annually.
Asthma is a chronic disease that involves episodes of bronchial constriction and airway inflammation. Asthma treatment focuses on symptom relief using different types of bronchodilators (medications used to open bronchial tubes) which can either work quickly by relaxing the involuntary muscles surrounding airways, or block acetylcholine and be much longer lasting.
Delivering drugs through inhalation has been practiced for thousands of years, for example inhaling fumes from plants in the Datura genus (also called Jimson Weed) was commonly used in India to treat asthma and several other disorders; however the plant is quite toxic, so don’t try it. Modern use of nebulizers for drug delivery can be traced to the invention of the atomizer by Euget-les-Bains in 1849 and development of the dose inhaler began in 1955. In the 1980’s and 90’s aerosol drug formulations became increasingly more sophisticated as research demonstrated the value of prompt delivery of deep lung doses of medicines for diseases such as asthma. Since both the drug and the delivery device can influence the overall properties of the formulation, each combination of active drug and device is a unique pharmaceutical formulation. Therefore research focused on the clinical effects of altering the deposition site of various classes of aerosolized drugs and the development of ergonomic and simple to operate inhalers.