Dry powder inhaler - Formulation aspects

Now a days the pulmonary route serves as an excellent route for administration of various drugs by inhalation. Inhalation by pulmonary route is most successful, since it reduces the quantity of dose required from other routes of administration, also avoids hepatic first pass metabolism and only smaller fraction of drug gets metabolised by liver. Inhaler is used to treat respiratory diseases like chronic inflammatory disorder such as asthma, chronic obstructive pulmonary disease (COPD) and other lung diseases characterized by obstruction of airflow and shortness of breath. The deposition of adequate amount of drug in the lung causes relief from symptoms of asthma and COPD. The inhalation delivery can be done via nebulizers, metered dose inhalers (MDI) and dry powder inhalers (DPI). The basic inhalation therapy model explains about the formulation, drug delivery device and patient receiving drug. Pharmaceutical dry powder inhalers are facilitated as an aerosolised form for the application to the patients by inhalation to treat respiratory diseases.