Respirable dry powder formulation of bleomycin for developing a pulmonary fibrosis animal model

Tranilast Inhibits Pulmonary Fibrosis by Suppressing TGFβ/SMAD2 Pathway

Purpose

Idiopathic pulmonary fibrosis (IPF) is characterized by the accumulation of extracellular matrix (ECM) protein in the lungs. Transforming growth factor (TGF) β-induced ECM protein synthesis contributes to the development of IPF. Tranilast, an anti-allergy drug, suppresses TGFβ expression and inhibits interstitial renal fibrosis in animal models. However, the beneficial effects of tranilast or its mechanism as a therapy for pulmonary fibrosis have not been clarified.

Methods

We investigated the in vitro effect of tranilast on ECM production and TGFβ/SMAD2 pathway in TGFβ2-stimulated A549 human alveolar epithelial cells, using quantitative polymerase chain reaction, Western blotting, and immunofluorescence. In vitro observations were validated in the lungs of a murine pulmonary fibrosis model, which we developed by intravenous injection of bleomycin.

Results

Treatment with tranilast suppressed the expression of ECM proteins, such as fibronectin and type IV collagen, and attenuated SMAD2 phosphorylation in TGFβ2-stimulated A549 cells. In addition, based on a wound healing assay in these cells, tranilast significantly inhibited cell motility, with foci formation that comprised of ECM proteins. Histological analyses revealed that the administration of tranilast significantly attenuated lung fibrosis in mice. Furthermore, tranilast treatment significantly reduced levels of TGFβ, collagen, fibronectin, and phosphorylated SMAD2 in pulmonary fibrotic tissues in mice.

Conclusion

These findings suggest that tranilast inhibits pulmonary fibrosis by suppressing TGFβ/SMAD2-mediated ECM protein production, presenting tranilast as a promising and novel anti-fibrotic agent for the treatment of IPF.

Adapting the Aerogen Mesh Nebulizer for Dried Aerosol Exposures Using the PreciseInhale Platform

Background: Many substances used in inhalation research are water soluble and can be administered as nebulized solutions. Typical examples are therapeutic, small-molecular agents, or macromolecules. Another category is a number of water-soluble agents used for airway diagnostics or disease modeling. Mesh nebulizers have facilitated well-controlled liquid aerosol exposures. Meanwhile, a benchtop inhalation platform, PreciseInhale, was developed for providing small-scale, well-controlled aerosol exposures in preclinical configurations. The purpose of the current research was to adapt the Aerogen mesh nebulizer to work within the PreciseInhale system for both cell culture and rodent exposures.

Methods: The wet aerosols produced with the Aerogen Pro nebulizer were dried out in an aerosol holding chamber by supplying dry carrier air, which was provided by passing the incoming ambient air through a column with silica gel. The nebulizer was installed in an aerosol holding chamber between an upstream flow-rate pneumotach and a downstream aerosol monitor. By pulsing, the nebulizer output was reduced to 1%–10% of continuous operation to better match the exposure ventilation requirements. Additional drying was obtained by mantling the holding chamber with dried paper.

Results and Conclusions: The nebulizer output was reduced to 3–30 μL/min and dried out before reaching the in vitro or in vivo exposure modules. Using solute concentrations in the range of 0.5%–2% (w/w), dried aerosols were produced with a mass median aerodynamic diameter of 1.5–2.0 μm, compared to the 4–5 μm droplets emitted by the nebulizer. Controlling the Aerogen nebulizer under a reduced output scheme within the PreciseInhale platform gave two major advantages: (i) by reducing aerosol output to better match exposure flow rates of single rodents, increased airway deposition yields were obtained in a range of 1%–10% relative to the nebulized amount of test substance and (ii) shrinking aerosol particle sizes through drying improved the peripheral lung deposition of test aerosols.

A review on recent technologies for the manufacture of pulmonary drugs

This review discusses recent developments in the manufacture of inhalable dry powder formulations. Pulmonary drugs have distinct advantages compared with other drug administration routes. However, requirements of drugs properties complicate the manufacture. Control over crystallization to make particles with the desired properties in a single step is often infeasible, which calls for micronization techniques. Although spray drying produces particles in the desired size range, a stable solid state may not be attainable. Supercritical fluids may be used as a solvent or antisolvent, which significantly reduces solvent waste. Future directions include application areas such as biopharmaceuticals for dry powder inhalers and new processing strategies to improve the control over particle formation such as continuous manufacturing with in-line process analytical technologies.

Biopharmaceutical Evaluation of Novel Cyclosporine A Nano-matrix Particles for Inhalation

PURPOSE

This study was undertaken to evaluate the biopharmaceutical properties of cyclosporine A (CsA)-loaded nano-matrix particles for inhalation.

METHODS

Nano-matrix particles of CsA with mannitol (nCsAm) were prepared by a flash nano-precipitation technique employing a multi-inlet vortex mixer and evaluated in terms of physicochemical properties, anti-inflammatory effect in the rat model of airway inflammation, pharmacokinetic behavior, and distributions of CsA to side-effect-related organs after intratracheal administration.

RESULTS

In nCsAm, spherical nano-particles of CsA were covered with mannitol and the mean particle size was 1.3 μm. The in vitro Next Generation Impactor analysis demonstrated fine inhalation performance with a fine particle fraction value of 65.8%. Intratracheal nCsAm (100 μg-CsA/rat) significantly attenuated the recruitment of inflammatory cells into the airway in the rat model of airway inflammation, followed by suppression of the inflammatory biomarkers. After intratracheal nCsAm at a pharmacologically effective dose (100 μg-CsA/rat), there was a 42-47-fold decrease in the distribution of CsA to side-effect-related organs such as the kidney and liver compared with oral CsA at a toxic dose (10 mg-CsA/kg), potentially leading to avoidance of systemic side-effects of CsA.

CONCLUSION

Upon these findings, nCsAm prepared with the flash nano-precipitation technique could be a novel dosage form of CsA for inhalation therapy of airway inflammation with a better safety margin.

Animal models of fibrotic lung disease

Interstitial lung fibrosis can develop as a consequence of occupational or medical exposure, as a result of genetic defects, and after trauma or acute lung injury leading to fibroproliferative acute respiratory distress syndrome, or it can develop in an idiopathic manner. The pathogenesis of each form of lung fibrosis remains poorly understood. They each result in a progressive loss of lung function with increasing dyspnea, and most forms ultimately result in mortality. To better understand the pathogenesis of lung fibrotic disorders, multiple animal models have been developed. This review summarizes the common and emerging models of lung fibrosis to highlight their usefulness in understanding the cell-cell and soluble mediator interactions that drive fibrotic responses. Recent advances have allowed for the development of models to study targeted injuries of Type II alveolar epithelial cells, fibroblastic autonomous effects, and targeted genetic defects. Repetitive dosing in some models has more closely mimicked the pathology of human fibrotic lung disease. We also have a much better understanding of the fact that the aged lung has increased susceptibility to fibrosis. Each of the models reviewed in this report offers a powerful tool for studying some aspect of fibrotic lung disease.