The application of prodrug technology in inhaled medicines

Compared with systemic administration such as oral delivery or injection, inhaled medicines directly locate in the respiratory tract to exert therapeutic effects, offering obvious advantages in the treatment of respiratory diseases. Marketed inhaled medicines are yet difficult to meet the clinical demands, and there are considerable challenges in the discovery and development of novel inhaled medicines due to the lack of experiences- and property-based rules for inhaled compounds. Personalized modification of candidate drugs through prodrug technology to meet the requirements of inhalation therapy is the current alternative approach for inhaled drug development. In this review, we intend to summary the applications of prodrug technology in the research of inhaled medicines over the past 20 years. These studies have shown that esterified prodrugs and macromolecule conjugates could effectively prolong lung retention; mannose modification or acid-sensitive bond connection can achieve targeted drug release in alveolar macrophages; personalized modified prodrugs can obtain suitable physicochemical properties for pulmonary delivery and reduce drug toxicity. In general, the application of prodrug technology can modify the physicochemical and biopharmaceutical properties of drugs and may promote the discovery and development of novel inhaled medicines.