Drug Permeation Characterization of Inhaled Dry Powder Formulations in Air-Liquid Interfaced Cell Layer Using an Improved, Simple Apparatus for Dispersion

Cryomilled electrospun nanofiber mats containing d-mannitol exhibit suitable for aerosol delivery of proteins

Dry powder inhalers (DPIs) are the first choice for inhalation drug development. However, some conventional DPI formulation processes require heating, which may damage high molecular weight drugs such as proteins and nucleic acids. In this study, we propose a novel DPI preparation process that avoids the use of heat. Dry powders were prepared by cryomilling nanofiber mats composed of polyvinyl alcohol, D(-)-mannitol (Man), and α-chymotrypsin (α-Chy) as the model drug using the electrospinning method. The addition of Man conferred high dispersibility and excellent in vitro aerosol performance to the nanofiber mat powder in a very short milling time (less than 0.5 min) as assessed using the Andersen cascade impactor. Powders were classified according to the degree of friability, and among these, nanofiber mats containing 15 % Man and milled for 0.25 min exhibited the highest aerosol performance. Nanofiber mats containing Man milled for less than 0.5 min also exhibited greater α-Chy enzymatic activity than a nebulized α-Chy solution. Furthermore, single inhalation induced no significant lung tissue damage as evidenced by lactate dehydrogenase activity assays of mouse bronchoalveolar lavage fluid. This novel DPI formulation process may facilitate the safe and efficient inhalational delivery of therapeutic proteins.

p53 dry gene powder enhances anti-cancer effects of chemotherapy against malignant pleural mesothelioma

Dry gene powder is a novel non-viral gene-delivery system, which is inhalable with high gene expression. Previously, we showed that the transfection of p16INK4a or TP53 by dry gene powder resulted in growth inhibitions of lung cancer and malignant pleural mesothelioma (MPM) in vitro and in vivo. Here, we report that dry gene powder containing p53- expression-plasmid DNA enhanced the therapeutic effects of cisplatin (CDDP) against MPM even in the presence of endogenous p53. Furthermore, our results indicated that the safe transfection with a higher plasmid DNA (pDNA) concentration suppressed MPM growth independently of chemotherapeutic agents. To develop a new therapeutic alternative for MPM patients without safety concerns over "vector doses", our in vitro data provide basic understandings for dry gene powder.

Pre-referral intranasal artesunate powder for cerebral malaria: a proof-of-concept study

Background

Malaria still kills young children in rural endemic areas because early treatment is not available. Thus, the World Health Organization recommends the administration of artesunate suppositories as pre-referral treatment before transportation to the hospital in case of severe symptoms with an unavailable parenteral and oral treatment. However, negative cultural perception of the rectal route, and limited access to artesunate suppositories, could limit the use of artesunate suppositories. There is, therefore, a need for an alternative route for malaria pre-referral treatment. The aim of this study was to assess the potential of intranasal route for malaria pre-referral treatment.

Methods

The permeability of artesunate through human nasal mucosa was tested in vitro. The Transepithelial Electrical Resistance (TEER) of the nasal mucosa was followed during the permeation tests. Beside, regional deposition of artesunate powder was assessed with an unidose drug delivery device in each nostril of a nasal cast. Artesunate quantification was performed using Liquid Chromatography coupled to tandem Mass Spectrometry.

Results

The experimental model of human nasal mucosa was successfully implemented. Using this model, artesunate powder showed a much better passage rate through human nasal mucosa than solution (26.8 ± 6.6% versus 2.1 ± 0.3%). More than half (62.3%) of the artesunate dose sprayed in the nostrils of the nasal cast was recovered in the olfactory areas (44.7 ± 8.6%) and turbinates (17.6 ± 3.3%) allowing nose-to-brain and systemic drug diffusion, respectively.

Conclusion

Artesunate powder showed a good permeation efficiency on human nasal mucosa. Moreover it can be efficiently sprayed in the nostrils using unidose device to reach the olfactory area leading to a fast nose-to-brain delivery as well as a systemic effect. Taken together, those results are part of the proof-of-concept for the use of intranasal artesunate as a malaria pre-referral treatment.

Aerosolization Performance, Antitussive Effect and Local Toxicity of Naringenin-Hydroxypropyl-β-Cyclodextrin Inhalation Solution for Pulmonary Delivery

The aim of present study was to evaluate the feasibility of a naringenin-hydroxypropyl-β-cyclodextrin (naringenin-HPβCD) inhalation solution for pulmonary delivery. Naringenin, a flavanone derived from citrus fruits, has been proven to exhibit excellent peripheral antitussive effect. To address the limitation of its poor oral bioavailability and low local concentration in the lung, a naringenin-HPβCD inhalation solution was prepared for pulmonary delivery. The aerosolization performance of formulation was evaluated by next generation impactor (NGI). Both dose-dependent and time-dependent antitussive effects of naringenin-HPβCD inhalation solution on acute cough induced by citric acid in guinea pigs were investigated. In vitro toxicity of naringenin-HPβCD inhalation solution in pulmonary Calu-3 cells was evaluated by MTS assay, and in vivo local toxicity investigation was achieved by assessing bronchoalveolar lavage (BALF) and lung histology after a 7-day inhalation treatment in guinea pigs. Fine particle fraction (FPF) of the formulation was determined as 53.09%. After inhalation treatment of 15 min, naringenin-HPβCD inhalation solution within the studied range of 0.2-3.6 mg/kg could dose-dependently reduce the cough frequency with the antitussive rate of 29.42-39.42%. Naringenin-HPβCD inhalation solution in concentration range of 100-400 μM did not decrease cell viability of Calu-3 cells, and the maximum effective dose (3.6 mg/kg) was non-toxic during the short-term inhalation treatment for guinea pigs. In conclusion, naringenin-HPβCD inhalation solution was capable for nebulization and could provide rapid response with reduced dose for the treatment of cough.

Comparative study of mucoadhesive and mucus-penetrative nanoparticles based on phospholipid complex to overcome the mucus barrier for inhaled delivery of baicalein

Efficient mucosal delivery remains a major challenge for the reason of the respiratory tract mucus act as a formidable barrier to nanocarriers by trapping and clearing foreign particulates. The surface property of nanoparticles determines their retention and penetration ability within the respiratory tract mucus. However, the interaction between nanoparticles and mucus, and how these interactions impact distribution has not been extensively investigated. In this study, polymeric nanoparticles loaded with a baicalein–phospholipid complex were modified with two kinds of polymers, mucoadhesive and mucus-penetrative polymer. Systematic investigations on the physicochemical property, mucus penetration, transepithelial transport, and tissue distribution were performed to evaluate the interaction of nanoparticles with the respiratory tract. Both nanoparticles had a similar particle size and good biocompatibility, exhibited a sustained-release profile, but showed a considerable difference in zeta potential. Interestingly, mucus-penetrative nanoparticles exhibited a higher diffusion rate in mucus, deeper penetration across the mucus layer, enhanced in vitro cellular uptake, increased drug distribution in airways, and superior local distribution and bioavailability as compared to mucoadhesive nanoparticles. These results indicate the potential of mucus-penetrative nanoparticles in design of a rational delivery system to improve the efficiency of inhaled therapy by promoting mucus penetration and increasing local distribution and bioavailability.

Characterization, in Vitro and in Vivo Evaluation of Naringenin-Hydroxypropyl-ß-Cyclodextrin Inclusion for Pulmonary Delivery

Naringenin, a flavonoid compound which exists abundantly in Citrus fruits, is proven to possess excellent antitussive and expectorant effects. However, the clinical applications of naringenin are restricted by its poor solubility and low local concentration by oral administration. The aim of the present study is to prepare a naringenin-hydroxypropyl-β-cyclodextrin (naringenin-HPβCD) inclusion as an inhalation solution for pulmonary delivery. The naringenin-HPβCD inclusion was characterized by phase solubility study, XRD, differential scanning calorimetry (DSC), proton nuclear magnetic resonance (¹HNMR), and two-dimensional rotating frame Overhauser effect spectroscopy (2D ROESY). The in vitro permeability of the inclusion was evaluated on Calu-3 cells and the pharmacokinetic profile of pulmonary delivery was investigated in Sprague-Dawley (SD) rats. Based on the linear model of phase solubility study, the relationship between naringenin and HPβCD was identified as A^L type with a 1:1 stoichiometry. XRD, DSC, and NMR studies indicated that the entire naringenin molecule is encapsulated into the cavity of HPβCD. HPβCD could increase the concentration of naringenin in the epithelium-lining fluid (ELF) of Calu-3 cells and act as a sustained release system for naringenin. The pharmacokinetic profile of naringenin-HPβCD inclusion showed rapid response and higher local concentration by pulmonary delivery. In conclusion, pulmonary delivery of naringenin-HPβCD inclusion is a promising formulation strategy, which could provide a new possibility for the clinical application of naringenin.

Th1/17-Biased Inflammatory Environment Associated with COPD Alters the Response of Airway Epithelial Cells to Viral and Bacterial Stimuli

Chronic obstructive pulmonary disease (COPD) is characterized by airway inflammation associated with a Th1/17-biased cytokine environment. Acute exacerbations of COPD (AECOPD) are most often triggered by respiratory infections, which elicit an exaggerated inflammatory response in these patients, via poorly defined mechanisms. We investigated the responses of airway epithelial cells (AECs) to infective stimuli in COPD and the effects of the Th1/17-biased environment on these responses. Cytokine expression was assessed following exposure to virus-like stimuli (poly I:C or imiquimod) or bacterial LPS. The effects of pretreatment with Th1/17 cytokines were evaluated in both primary AECs and the Calu-3 AEC cell line. We found that poly I:C induced increased expression of the proinflammatory cytokines IL1β, IL6, CXCL8, and TNF and IFN-β1 in AECs from both control subjects and COPD patients. Expression of IL1β in response to all 3 stimuli was significantly enhanced in COPD AECs. Primary AECs pretreated with Th1/17 cytokines exhibited enhanced expression of mRNA for proinflammatory cytokines in response to poly I:C. Similarly, Calu-3 cells responded to virus-like/bacterial stimuli with increased expression of proinflammatory cytokines, and a Th1/17 environment significantly enhanced their expression. Furthermore, increased expression of pattern recognition receptors for viruses (TLR3, TLR7, IFIH1, and DDX58) was induced by Th1/17 cytokines, in both primary AECs and Calu-3 cells. These findings suggest that the Th1/17-biased environment associated with COPD may enhance the proinflammatory cytokine response of AECs to viral and bacterial infections and that increased signaling via upregulated receptors may contribute to exaggerated inflammation in virus-induced AECOPD.

Application of RPMI 2650 as a cell model to evaluate solid formulations for intranasal delivery of drugs

During the development of intranasal drug delivery systems for local/systemic effect or brain targeting, it is necessary to assess its cytotoxicity and drug transport through nasal epithelium. In order to avoid animal experiments or the use of excised tissues, in vitro cell models, such as RPMI 2650 cells, are being preferred during recent years. Nevertheless, the deposition of solid formulations into nasal cell layers with further transepithelial transport rate of drugs has been poorly studied or reported. Thus, the purpose of this work is to further investigate RPMI 2650 cell line as an effective alternative to animal tissues for solid drug-loaded formulations cytotoxicity and drug permeation studies in order to become an option as a tool for drug discovery. Furthermore, we wanted to determine the extent to which the administration of drugs in particulate forms would differ in relation to the permeability of the same compounds applied as solutions. RPMI 2650 cells were cultured in submersed or at air-liquid interface conditions and characterized regarding transepithelial electrical resistance (TEER) and production of mucus. Pure ketoprofen (used as model compound) and five formulations loaded with same drug, namely solid lipid particles (Gelucire 43/01™), structured lipid particles (Gelucire 43/01™:Glyceryl monooleate) and aerogel microparticles (Alginate, Alginate:Pectin, Alginate:Carrageenan), were evaluated with RPMI 2650 model in terms of cytotoxicity and permeability of drug (applied as solution, dispersion or powder+buffer). RPMI 2650 cells were capable to grow in monolayer and multilayer, showing the same permeability as excised human nasal mucosa for sodium fluorescein (paracellular marker), with analogous TEER values and production of mucus, as referred by other authors. None of the powders showed cytotoxicity when applied to RPMI 2650 cells. Regarding permeation of drug through cell layers, not only the form of application of powders but also their physical and chemical properties affected the final permeation of active pharmaceutical ingredient. Aerogel microparticles administered directly to the cell layer (powder+buffer) exhibited the highest permeation-enhancing effect compared to the pure drug, which can be attributed to the mucoadhesive properties of the materials composing the carriers, proving to be an attractive formulation for nasal drug delivery. According to these results, RPMI 2650 showed to be a promising alternative to ex vivo or in vivo nasal models for cytotoxicity and evaluation of drug permeability of nasal drug-loaded formulations.

Safety Evaluation of Dry Powder Formulations by Direct Dispersion onto Air-Liquid Interface Cultured Cell Layer

Most safety evaluations of dry powder inhalers (DPIs) using cultured cells have been performed with dry powder formulations dissolved in a medium. However, this method is not considered to be suitable to evaluate the safety of inhaled dry powder formulations correctly since it cannot reflect the actual phenomenon on the respiratory epithelial surface. In this study, we established a novel in-vitro safety evaluation system suitable for DPIs by combining an air-liquid interface cultured cell layer and a device for dispersing dry powders, and evaluated the safety of candidate excipients of dry powders for inhalation. The safety of excipients (sugars, amino acids, cyclodextrins, and positive controls) in solutions was compared using submerged cell culture systems with a conventional 96-well plate and Transwell(®). The sensitivity of the cells grown in Transwell(®) was lower than that of those grown in the 96-well plate. Dry powders were prepared by spray-drying and we evaluated their safety with a novel in-vitro safety evaluation system using an air-liquid interface cultured cell layer. Dry powders decreased the cell viability with doses more than solutions. On the other hand, dissolving the dry powders attenuated their cytotoxicity. This suggested that the novel in-vitro safety evaluation system would be suitable to evaluate the safety of DPIs with high sensitivity.

Layer-by-layer surface decoration of electrospun nanofibrous meshes for air–liquid interface cultivation of epidermal cells

PEG multilayered nanofibrous mat for air–liquid interface cell cultivation.