Microspheres as pulmonary delivery systems - A review

Microspheres are one of the delivery systems, which can be used to protect drugs or proteins especially for pulmonary purposes since these particles can be a direct target to the lung and their mucoadhesive properties. Their advantages could help cure pulmonary diseases. There are several methods of polymers to form microspheres depending on the physicochemical characteristics of polymers. In this review, we aimed to discuss methods to produce microspheres from conventional to advanced techniques, and various polymers that can be designed to form microspheres, and aerosolization properties of the inhalable particles for pulmonary delivery were discussed. With this comprehensive review, our findings will enhance pharmaceutical knowledge, promote wide uses of microspheres, and produce new techniques to prepare inhalable pulmonary microspheres.