Dry Powder Inhalation Microparticles (Alginate, Carrageenan, Chitosan, and Combination Polymers): A Review on Characteristics and In Vivo Activity

Dry Powder Inhaler (DPI) delivers one or more drug substances to the site of action through the inhalation route. It is used to treat respiratory diseases characterized by airflow obstruction and shortness of breath, including asthma and chronic obstructive pulmonary disease (COPD), respiratory infections, and cystic fibrosis. The inhalation route offers further potential for systemic drug delivery. DPI products consist of a drug formulation (the drug constituent part) and a container closure system. A DPI drug formulation contains the drug substance and excipients, including a drug carrier. Drug formulation plays an essential role in producing an effective inhalable medication. Formulating dry powders for inhalation involves micronization with various methods using various excipients, such as lipids, lactose, and polymers. Each one offers its unique advantages and disadvantages, depending on the therapeutic agent being formulated. This review will be highlighting the use of biodegradable polymers, such as alginate, chitosan, carrageenan, and combination polymers, in inhalation drug delivery systems. Particularly polymers microparticles, known as microspheres, received much attention because of their sustained and prolonged release properties and their application for targeting respiratory diseases. Moreover, this review will also summarize the in vivo drug deposition, lung localization, and histopathological study of microparticles.