Pulmonary pharmaceutical formulations are targeted for the treatment of respiratory diseases. However, their application is limited due to the physiological characteristics of the lungs, such as branching structure, mucociliary and macrophages, as well as certain properties of the drugs like particle size and solubility. Nano-formulations can ameliorate particle sizes and improve drug solubility to enhance bioavailability in the lungs. The nano-formulations for lungs reviewed in this article can be classified into nanocarriers, no-carrier-added nanosuspensions and polymer-drug conjugates. Compared with conventional inhalation preparations, these novel pulmonary pharmaceutical formulations have their own advantages, such as increasing drug solubility for better absorption and less inflammatory reaction caused by the aggregation of insoluble drugs; prolonging pulmonary retention time and reducing drug clearance; improving the patient compliance by avoiding multiple repeated administrations. This review will provide the reader with some background information for pulmonary drug delivery and give an overview of the existing literature about nano-formulations for pulmonary application to explore nano-strategies for improving the bioavailability of pulmonary pharmaceutical formulations.

肺部药物制剂的目标是治疗呼吸系统疾病。但是，由于肺的生理特性（例如分支结构，粘膜纤毛和巨噬细胞）以及药物的某些特性（例如粒度和溶解度），它们的应用受到了限制。纳米制剂可以改善粒径并改善药物溶解度，以增强肺部的生物利用度。本文概述的用于肺部的纳米制剂可分为纳米载体，无载体的纳米悬浮液和聚合物-药物缀合物。与传统的吸入制剂相比，这些新型的肺部药物制剂具有各自的优势，例如增加药物溶解度以实现更好的吸收，并减少因不溶性药物聚集而引起的炎症反应；延长肺保留时间并减少药物清除率；通过避免多次重复给药来改善患者依从性。这篇综述将为读者提供一些有关肺部药物输送的背景信息，并概述有关用于肺部应用的纳米制剂的现有文献，以探索改善肺部药物制剂生物利用度的纳米策略。