Inhaler Characteristics in Asthma

Abstract

The history of inhaled therapy goes back a surprisingly long way. More than 4,000 years ago, in India, the vapour of plants from the nightshade family placed on hot bricks was inhaled to alleviate breathing difficulties. The bronchodilators, derived from these plants, and compounds related to them, have played a significant part in therapeutic aerosol delivery over the years and remain important in the treatment of lung diseases today. The development of inhaled therapy has accelerated over the past 60 years with the arrival of the first truly portable inhaler in 1956 to relieve the symptoms of asthma. Initially, only bronchodilators were delivered from these devices, but as the true nature of asthma was revealed, inhaled corticosteroids were introduced to treat the underlying inflammation that is a major component of asthma. Further advances have led to long-acting bronchodilators becoming available, and combination therapies containing both longacting bronchodilators and corticosteroids in one inhaler. Asthma therapy has come a long way in a comparatively short time with over 230 device and drug combinations available for treating the disease. However, despite enormous investment asthma remains a huge healthcare problem. The number of people with asthma continues to grow with over 300 million people affected worldwide and 250,000 annual deaths attributed to the disease. It affects people of all ages and has a varying degree of severity. In this article, we look at the ideal characteristics for asthma inhalers and highlight some of the most important reasons for the failure of current asthma treatments.