[Recent progress of dry powder inhalation of proteins and peptides]

To provide theoretical and practical basis for the successful formulation design of physically-mixed inhalation dry powder of proteins and peptides, related references were collected, analyzed and summarized. In this review drug micronization technology and commonly used carriers for inhalation dry powder preparation were introduced. For proteins and peptides, supercritical fluid technology and spray-drying are more suitable because of their capabilities of keeping drug activity. Being approved by U. S. Food and Drug Administration, lactose has been extensively used as carriers in many inhalation products. Formulation and process factors influencing drug deposition in the lung, including carrier properties, drug-carrier ratio, blending order, mixing methods, mixing time and the interaction between drug and carrier, were elucidated. The size, shape and surface properties of carries all influence the interaction between drug and carrier. Besides, influence of micromeritic properties of the dry powder, such as particle size, shape, density, flowability, charge, dispersibility and hygroscopicity, on drug deposition in the lung was elaborated. Among these particle size plays the most crucial role in particle deposition in the lung. Moreover, based on the mechanisms of powder dispersity, some strategies to improve drug lung deposition were put forward, such as adding carrier fines, adding adhesive-controlling materials and reprocessing micronized drug. In order to design physically-mixed inhalation dry powder for proteins and peptides with high lung deposition, it is essential to study drug-carriers interactions systematically and illustrate the potential influence of formulation, process parameters and micromeritic properties of the powder.