Nano-drug delivery systems offer significant benefits, including high specific surface area, structural and functional diversity, and surface modifiability. When formulated as inhalable nano-formulation, these can not only enable precise pulmonary drug delivery but also improve pulmonary bioavailability and enhance thera-peutic efficacy. Currently, there are four types of inhalable nano-formulations for the treatment of respiratory diseases. Inhalable liquid preparations exhibit facile manufactur-ability and broad applicability yet demonstrate compromised stability during aerosolization. Through structure optimization, surface modification, dispersion medium optimization and device improvement, the atomization stability of nano-drug has been enhanced. Pressurized metered-dose inhalers loaded with nano-drugs face technical challenges: conventional propellants may dissolve nano-carriers, whereas co-solvents like ethanol compromise delivery efficiency. Thus, it is necessary to develop novel propellants that provide thermodynamic stability and optimal delivery performance. Nano-drug formulations in dry powder inhalers exhibit relatively favorable physical stability, however, pulmonary delivery efficiency and nanoparticles integrity during processing remain problematic. Pulmonary delivery efficiency can be improved by employing strategies such as blending excipients to promote the re-dispersibility of nanoparticle agglomerates, optimizing the design of microcarrier, and innovating preparation processes. In contrast, soft mist inhalers are an ideal option for pulmonary delivery of nano-drugs owing to their gentle and efficient atomization properties to maintain nano-drug integrity. This review summarizes the inhalable nano-formulations and focuses on challenges and proposed strategies encoun-tered in integrating nano-drug delivery systems and inhalation drug delivery systems. It aims to provide references for the future development of inhalable nano-formulations.
Administration, Inhalation ; Humans ; Drug Delivery Systems/methods* ; Nanoparticles ; Dry Powder Inhalers ; Nanoparticle Drug Delivery System ; Drug Compounding ; Metered Dose Inhalers ; Drug Carriers

Epigallocatechin-3-gallate (EGCG), a bioactive polyphenol abundant in green tea, has garnered significant attention for its diverse therapeutic applications, ranging from antioxidant and anti-inflammatory effects to potential anticancer properties. Despite its immense promise, the practical utilization of EGCG in therapeutic settings as a medication has been hampered by inherent limitations of this drug, including poor bioavailability, instability, and rapid degradation. This review comprehensively explores the current challenges associated with the application of EGCG and evaluates the potential of nanoparticle-based formulations in addressing these limitations. Nanoparticles, with their unique physicochemical properties, offer a platform for the enhanced stability, bioavailability, and targeted delivery of EGCG. Various nanoparticle strategies, including polymeric nanoparticle, micelle, lipid-based nanocarrier, metal nanoparticle, and silica nanoparticle, are currently employed to enhance EGCG stability and pharmacological activity. This review concludes that the particle sizes of most of these formulated nanocarriers fall within 300 nm and their encapsulation efficiency ranges from 51% to 97%. Notably, the pharmacological activities of EGCG-loaded nanoparticles, such as antioxidative, anti-inflammatory, anticancer, and antimicrobial effects, are significantly enhanced compared to those of free EGCG. By critically analyzing the existing literature and highlighting recent advancements, this article provides valuable insights into the promising prospects of nanoparticle-mediated EGCG formulations, paving the way for the development of more effective and clinically viable therapeutic strategies.
Animals ; Humans ; Anti-Inflammatory Agents/administration & dosage* ; Antineoplastic Agents/administration & dosage* ; Antioxidants/administration & dosage* ; Biological Availability ; Catechin/analogs & derivatives* ; Micelles ; Particle Size ; Nanoparticle Drug Delivery System/chemistry*

Natural compounds demonstrate unique therapeutic advantages for cancer treatment, primarily through direct tumor suppression or interference with the tumor microenvironment (TME). Glycyrrhizic acid (GL), a bioactive ingredient derived from the medicinal herb Glycyrrhiza uralensis Fisch., and its sapogenin glycyrrhetinic acid (GA), have been recognized for their ability to inhibit angiogenesis and remodel the TME. Consequently, the combination of GL with other therapeutic agents offers superior therapeutic benefits. Given GL's amphiphilic structure, self-assembly capability, and liver cancer targeting capacity, various GL-based nanoscale drug delivery systems have been developed. These GL-based nanosystems exhibit angiogenesis suppression and TME regulation properties, synergistically enhancing anti-cancer effects. This review summarizes recent advances in GL-based nanosystems, including polymer-drug micelles, drug-drug assembly nanoparticles (NPs), liposomes, and nanogels, for cancer treatment and tumor postoperative care, providing new insights into the anti-cancer potential of natural compounds. Additionally, the review discusses existing challenges and future perspectives for translating GL-based nanosystems from bench to bedside.
Animals ; Humans ; Antineoplastic Agents/therapeutic use* ; Glycyrrhizic Acid/therapeutic use* ; Liposomes/chemistry* ; Micelles ; Nanoparticles/chemistry* ; Neoplasms/pathology* ; Tumor Microenvironment/drug effects* ; Nanoparticle Drug Delivery System/therapeutic use*

Essential oils (EOs) are natural, volatile substances derived from aromatic plants. They exhibit multiple pharmacological effects, including antibacterial, anticancer, anti-inflammatory, and antioxidant properties, with broad application prospects in health care, food, and agriculture. However, the instability of volatile components, which are susceptible to deterioration under light, heat, and oxygen exposure, as well as limited water solubility, have significantly impeded the development and application of EOs. Porous nanoclays are natural clay minerals with a layered structure. They possess unique structural characteristics such as large pore size, regular distribution, and tunable particle size, which are extensively utilized in drug delivery, adsorption separation, reaction catalysis, and other fields. Natural-derived porous nanoclays have garnered considerable attention for the encapsulation and delivery of EOs. This review comprehensively summarizes the structure, types, and properties of natural-derived porous nanoclays, focusing on the structural characteristics of porous nanoclays such as montmorillonite, palygorskite, halloysite, kaolinite, vermiculite, and natural zeolite. It also examines research advances in their delivery of EOs and explores engineering strategies to enhance the delivery of EOs by natural-derived porous nanoclays. Finally, various applications of natural-derived porous nanoclays for EOs in antibacterial, food preservation, repellent, and insecticide aspects are presented, providing a reference for the development and application of EOs.
Humans ; Nanoparticles/chemistry* ; Oils, Volatile/administration & dosage* ; Porosity ; Nanoparticle Drug Delivery System/chemistry*