Around 300 million people have asthma across the planet. For more than fifty years, many of these have benefited from the metered dose inhaler. But the idea to create a device that delivers measured particles of aerosol medicines into the lungs did not come from a scientist, but from a thirteen-year-old girl. Susie Maison asked her father why her asthma spray could not be put into a hairspraylike device instead of the bulky, glass nebulizer she struggled with. Mr. Maison, then president of Riker Laboratories (acquired by 3M Pharmaceuticals in 1970), took the idea to the company where a team looked into making it a reality.
They examined devices used for aerosol perfumes and tried mixing the medications, isoprotenerol or epinephrine with alcohol, ascorbic acid, and chlorofluorocarbon propellants. Early trials showed the effectiveness of this method of drug delivery and the first pressurized metered dose inhalers were launched in March 1956. An amyl nitrate inhaler for angina was launched the same year. With suspension formulations came the first nasal inhaler in 1957 Refinement of both oral and nasal inhalers led to better designs, and by 1970 the first breath actuated inhaler was launched. Use of chlorofluorocarbon propellants switched to hydrofluorocarbon ones with laws to protect the ozone layer in 1987. This was a challenge to the industry as all materials had to be reworked and retested for efficacy and safety.
Metered dose inhalers are still being improved to become more effective and easier to use. Increased understanding of how particles work has meant products that were less receptive to conventional metered dose inhalers, such as insulin, have at last found their way into inhaled formulations.
