The influence of particle physicochemical properties on delivery of drugs by dry powder inhalers to the lung

Drug delivery by inhalation has been routinely used for the treatment of localized diseases such as asthma and COPD. In addition to local delivery the pulmonary route has more recently been found to be a suitable for delivering of drugs for the treatment of systemic diseases, such as diabetes. Pressured metered dose inhaler (pMDI) have historically been the main device platform for delivering to the lung, however in the last two decades the dry powder inhaler (DPI) has become much more popular. This increase in popularity for the DPI has lead to a wide range of DPI devices being commercially available. A high quality DPI needs to demonstrate reproducibility of dose delivery to the site of action, ease of processing and stability. In order to achieve these characteristics a well designed DPI (device and formulation) is required. This review focuses on the formulation design aspects of the DPI product demonstrating how the physicochemical properties of carrier and drug such as particle shape, flow, surface area, surface texture, density and the presence of the third components in DPI formulation affect the delivery of drugs from DPI to the lung. © 2011 by Nova Science Publishers, Inc. All rights reserved