ABSTRACT
Pharmacologically active substances have been administered to humans for thousands of years. However, it is only in relatively recent times that the true nature of drug delivery to the human body has become an exact science. Today, drugs are delivered via many portals into the body using a variety of dosage forms which allow medicament administration, for example, orally or parenterally. One relatively recent pharmaceutical development is delivery via the lung. Although the breathing of “vapors” has been used since ancient times as a way of relieving respiratory problems, the effective acceptance and mass commercialization of inhaled respiratory medicines was not achieved until 1948 when Abbot Laboratories developed the Aerohaler for inhaled penicillin-G powder and then revolutionized the field in 1955 with the advent of the pressurized metered dose inhaler (pMDI) (1,2). Since this inception, the range of inhaler products and medicaments has grown and expanded to encompass alternative drug delivery systems, namely those based on the dry powder inhaler (DPI), and combination products.
