Excipient-Free Inhalable Microparticles of Azithromycin Produced by Electrospray: A Novel Approach to Direct Pulmonary Delivery of Antibiotics

Heparin-azithromycin microparticles show anti-inflammatory effects and inhibit SARS-CoV-2 and bacterial pathogens associated to lung infections

Pulmonary infections are a leading cause of morbidity and mortality worldwide, a situation exacerbated by the COVID-19. Azithromycin (AZM) is used orally to treat pulmonary infections due to its ability to accumulate in lung tissues and immune cells after oral administration. Sulfated polysaccharides, such as heparin, are known to inhibit SARS-CoV-2 entry. This study presents a novel approach focused on developing a dry powder inhaler of AZM-loaded microparticles composed of either heparin or its derivatives. The microparticle formulations exhibited potent antiviral activity against SARS-CoV-2 (IC50 ≤ 95 nM) while retaining superior antibacterial efficacy against Streptococcus pneumoniae and Pseudomonas aeruginosa compared to free AZM (MIC ≤15 μg/mL). Importantly, at bactericidal concentrations, no cytotoxic effects were observed on mammalian cells, including Calu-3 cells and red blood cells. The formulations demonstrated effective alveolar aerodynamic deposition (MMAD ranging from 1 μm to 3 μm) with a Fine Particle Fraction below 5 μm close to 50 %. Adopting a conservative estimate of 20 mL for the pulmonary epithelial lining fluid volume in healthy adults, efficacious local concentrations of sulfated polysaccharides and AZM would be delivered to the lung using this multifaceted strategy which holds promise for the treatment of bacterial pulmonary infections associated with COVID-19.

Nanocrystal Agglomerates of Curcumin Prepared by Electrospray Drying as an Excipient-Free Dry Powder for Inhalation

Curcumin has shown beneficial effects on pulmonary diseases with chronic inflammation or abnormal inflammatory responses, including chronic obstructive pulmonary disease, asthma, and pulmonary fibrosis. Clinical applications of curcumin are limited due to its chemical instability in solution, low water solubility, poor oral bioavailability, and intestinal and liver first-pass metabolism. Pulmonary delivery of curcumin can address these challenges and provide a high concentration in lung tissues. The purpose of the current work was to prepare a novel inhalable dry powder of curcumin nanocrystals without added excipients using electrospray drying (ED) with improved dissolution and aerosolization properties. ED of curcumin was performed at 2 and 4% w/v concentrations in acetone. Physicochemical properties of the formulated powders were evaluated by powder X-ray diffraction (PXRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), density and powder flow measurements, and in vitro dissolution. The in vitro deposition studies were conducted using next-generation impactor (NGI) and aerosol performance and aerodynamic particle size parameters were calculated for prepared formulations. ED could produce agglomerates of nanocrystals with a size of about 500 nm at an acceptable yield of about 50%. PXRD and FTIR data revealed that prepared nanocrystals were in a stable crystalline state. The bulk and tapped density of prepared agglomerates were in the range appropriate for pulmonary delivery. Formed nanocrystals could significantly improve the dissolution rate of water-insoluble curcumin. The optimized formulation exhibited acceptable recovered dose percentage, high emitted dose percentage, optimum mean mass median aerodynamic diameter, small geometric standard deviation, and high fine-particle fraction that favors delivery of curcumin to the deep lung regions. The ED proved to be an efficient technique to prepare curcumin nanocrystals for pulmonary delivery in a single step, at a mild condition, and with no surfactant.

A new frontier in precision medicine: Exploring the role of extracellular vesicles in chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) is a chronic inflammatory airway disease characterized by progressive respiratory difficulties. It has a high incidence and disability rate worldwide. However, currently there is still a lack of highly effective treatment methods for COPD, only symptom relief is possible. Therefore, there is an urgent need to explore new treatment options. Almost all cells can secrete extracellular vesicles (EVs), which participate in many physiological activities by transporting cargoes and are associated with the pathogenesis of various diseases. Recently, many scholars have extensively studied the relationship between COPD and EVs, which has strongly demonstrated the significant impact of EVs from different sources on the occurrence and development of COPD. Therefore, EVs are a good starting point and new opportunity for the diagnosis and treatment of COPD. In this review, we mainly describe the current mechanisms of EVs in the pathogenesis of COPD, also the relationship between diagnosis, prognosis, and treatment. At the same time, we also introduce some new methods for COPD therapy based on EVs. It is hoped that this article can provide new ideas for future research and contribute to the development of precision medicine.

Sensitive SERS detection of oral squamous cell carcinoma-related miRNAs in saliva via a gold nanohexagon array coupled with hybridization chain reaction amplification

In this work, a highly specific and sensitive method for the detection of dual miRNAs was successfully developed by a hybridization chain reaction (HCR) amplification coupled with surface-enhanced Raman scattering (SERS) on Au-Ag hollow nanoparticles (Au-Ag HNPs) and a gold nanohexagon (AuNH) array. Two Raman reporter-labelled and hairpin DNA-modified Au-Ag HNPs acted as SERS probes (Au-Ag HNPs@4-MBA@HP_1-1, Au-Ag HNPs@4-MBA@HP_2-1, Au-Ag HNPs@DTNB@HP_1-2, and Au-Ag HNPs@DTNB@HP_2-2), and the hairpin DNA-modified AuNH array acted as the capture substrate. The HCR process could be triggered by the presence of target miRNAs, and long DNA hybridization chains on the substrate were formed by self-assembly rapidly, causing significant signal enhancement. Using the mentioned strategy, a low detection limit (LOD) of 6.51 aM for miR-31 and 6.52 aM for miR-21 in human saliva were obtained, showing the biosensor's remarkable sensitivity. The proposed biosensor also displays a significant specificity in detecting target miRNAs by introducing different interfering factors. This method has been successfully applied to detect and identify miR-21 and miR-31 in saliva from oral squamous cell carcinoma (OSCC) patients and healthy subjects. The results were consistent with those of the traditional test method in detecting target miRNAs, which confirmed the good accuracy of our method. Hence, the new assay method has great potential to be a valuable platform for detecting miRNAs in the early diagnosis of OSCC.