Pulmonary tract is one of the oldest routes used for administration of drugs. During the past decade, the lung has been very attractive for achieving systemic and local absorption of various drugs, particularly for those drugs that exhibit poor bioavailability when administered by the oral or parenteral route. Polymers are considered to be high interest because of their greater capability to encapsulate drugs to prolong the effect of drugs. They have been used to make drug delivery systems such as nanoparticles and microparticles. Natural and synthetic polymers have been studied substantially for pulmonary drug delivery to obtain controlled drug delivery. The physicochemical characteristics of the polymers used in dry powders are potently fundamental for increasing the performance of the inhalation system. In this entry we focus on the properties of natural and synthetic polymers in dry powder inhaler systems and review their application in inhalation drug delivery systems.
