Dose tolerability of chronically inhaled voriconazole solution in rodents

Inhaled Antifungal Agents for Treatment and Prophylaxis of Bronchopulmonary Invasive Mold Infections

Pulmonary mold infections are life-threatening diseases with high morbi-mortalities. Treatment is based on systemic antifungal agents belonging to the families of polyenes (amphotericin B) and triazoles. Despite this treatment, mortality remains high and the doses of systemic antifungals cannot be increased as they often lead to toxicity. The pulmonary aerosolization of antifungal agents can theoretically increase their concentration at the infectious site, which could improve their efficacy while limiting their systemic exposure and toxicity. However, clinical experience is poor and thus inhaled agent utilization remains unclear in term of indications, drugs, and devices. This comprehensive literature review aims to describe the pharmacokinetic behavior and the efficacy of inhaled antifungal drugs as prophylaxes and curative treatments both in animal models and humans.

Aerosolizable Lipid-Nanovesicles Encapsulating Voriconazole Effectively Permeate Pulmonary Barriers and Target Lung Cells

The entire world has recently been witnessing an unprecedented upsurge in microbial lung infections. The major challenge encountered in treating the same is to ensure the optimum drug availability at the infected site. Aerosolization of antimicrobials, in this regard, has shown immense potential owing to their localized and targeted effect. Efforts, therefore, have been undertaken to systematically develop lung-phosphatidylcholine-based lipid nanovesicles of voriconazole for potential management of the superinfections like aspergillosis. LNVs, prepared by thin-film hydration method, exhibited a globule size of 145.4 ± 19.5 nm, polydispersity index of 0.154 ± 0.104 and entrapment efficiency of 71.4 ± 2.2% with improved in vitro antifungal activity. Aerodynamic studies revealed a microdroplet size of ≤5 μm, thereby unraveling its promise to target the physical barrier of lungs effectively. The surface-active potential of LNVs, demonstrated through Langmuir-Blodgett troughs, indicated their ability to overcome the biochemical pulmonary surfactant monolayer barrier, while the safety and uptake studies on airway-epithelial cells signified their immense potential to permeate the cellular barrier of lungs. The pharmacokinetic studies showed marked improvement in the retention profile of voriconazole in lungs following LNVs nebulization compared to pristine voriconazole. Overall, LNVs proved to be safe and effective delivery systems, delineating their distinct potential to efficiently target the respiratory fungal infections.

Nebulised surface-active hybrid nanoparticles of voriconazole for pulmonary Aspergillosis demonstrate clathrin-mediated cellular uptake, improved antifungal efficacy and lung retention

BACKGROUND

Incidence of pulmonary aspergillosis is rising worldwide, owing to an increased population of immunocompromised patients. Notable potential of the pulmonary route has been witnessed in antifungal delivery due to distinct advantages of direct lung targeting and first-pass evasion. The current research reports biomimetic surface-active lipid-polymer hybrid (LPH) nanoparticles (NPs) of voriconazole, employing lung-specific lipid, i.e., dipalmitoylphosphatidylcholine and natural biodegradable polymer, i.e., chitosan, to augment its pulmonary deposition and retention, following nebulization.

RESULTS

The developed nanosystem exhibited a particle size in the range of 228-255 nm and drug entrapment of 45-54.8%. Nebulized microdroplet characterization of NPs dispersion revealed a mean diameter of  ≤ 5 μm, corroborating its deep lung deposition potential as determined by next-generation impactor studies. Biophysical interaction of LPH NPs with lipid-monolayers indicated their surface-active potential and ease of intercalation into the pulmonary surfactant membrane at the air-lung interface. Cellular viability and uptake studies demonstrated their cytocompatibility and time-and concentration-dependent uptake in lung-epithelial A549 and Calu-3 cells with clathrin-mediated internalization. Transepithelial electrical resistance experiments established their ability to penetrate tight airway Calu-3 monolayers. Antifungal studies on laboratory strains and clinical isolates depicted their superior efficacy against Aspergillus species. Pharmacokinetic studies revealed nearly 5-, 4- and threefolds enhancement in lung AUC, Tmax, and MRT values, construing significant drug access and retention in lungs.

CONCLUSIONS

Nebulized LPH NPs were observed as a promising solution to provide effective and safe therapy for the management of pulmonary aspergillosis infection with improved patient compliance and avoidance of systemic side-effects.

Development of Remdesivir as a Dry Powder for Inhalation by Thin Film Freezing

Remdesivir exhibits in vitro activity against SARS-CoV-2 and was granted approval for emergency use. To maximize delivery to the lungs, we formulated remdesivir as a dry powder for inhalation using thin film freezing (TFF). TFF produces brittle matrix nanostructured aggregates that are sheared into respirable low-density microparticles upon aerosolization from a passive dry powder inhaler. In vitro aerodynamic testing demonstrated that drug loading and excipient type affected the aerosol performance of remdesivir. Remdesivir combined with optimal excipients exhibited desirable aerosol performance (up to 93.0% FPF_{< 5 µm}; 0.82 µm mass median aerodynamic diameter). Remdesivir was amorphous after the TFF process, which benefitted drug dissolution in simulated lung fluid. TFF remdesivir formulations are stable after one month of storage at 25 °C/60% relative humidity. An in vivo pharmacokinetic evaluation showed that TFF remdesivir–leucine was poorly absorbed into systemic circulation while TFF remdesivir-Captisol^® demonstrated increased systemic uptake compared to leucine. Remdesivir was hydrolyzed to the nucleoside analog GS-441524 in the lung, and levels of GS-441524 were greater in the lung with leucine formulation compared to Captisol^®. In conclusion, TFF technology produces high-potency remdesivir dry powder formulations for inhalation that are suitable to treat patients with COVID-19 on an outpatient basis and earlier in the disease course where effective antiviral therapy can reduce related morbidity and mortality.

Clinical Feasibility and Airway Deposition of Nebulized Voriconazole in Healthy Horses

Voriconazole (VRC) is a potential treatment for pneumomycosis in horses. The objectives of this study were to determine if the delivery of Vfend using a Flexineb nebulizer produced clinically significant [VRC] in lower airways. The hypothesis was that [VRC] after delivery by nebulization would be greater in the pulmonary epithelial lining fluid than plasma. A secondary objective was to determine [VRC] in upper airways through the collection of nasopharyngeal wash (NPW) samples. Voriconazole solution [Vfend-6.25 mg/mL, 100 (n = 2), 200 (n = 3), 500 (n = 1) mg] was nebulized once in 6 healthy geldings. Clinical responses, duration of nebulization, and [VRC] at various time points (up to 8 hours) in plasma, bronchoalveolar lavage fluid (BALF) supernatant and cell pellet, and NPW samples were recorded. Voriconazole (Vfend-6.25 mg/mL, 200 mg) was nebulized in 5 additional, healthy geldings, and [VRC] was measured in NPW samples pre- and postnebulization at time points up to 8 hours. The antifungal activity of BALF and NPW samples was determined using agar disk diffusion. Concentrations of voriconazole were below detection in plasma, BALF supernatant, and cell pellets for all time points and doses except the BALF cell pellet (0.4 μg/g) immediately after nebulization of 500 mg. For 5 horses, administered 200 mg of Vfend, mean [VCR] in NPW at the end of nebulization and 1, 6, and 8 hours postnebulization were: 30.8 ± 29, 1.0 ± 0.84, 0.2 ± 0.19, and 0.34 ± 0.67 μg/mL, respectively. Only NPW samples obtained immediately postnebulization showed antifungal activity. A nebulized Vfend solution is not recommended for the treatment of pneumomycosis in horses.

Porous and highly dispersible voriconazole dry powders produced by spray freeze drying for pulmonary delivery with efficient lung deposition

Systemic administration of antifungal agents for the treatment of pulmonary aspergillosis is limited by the poor lung deposition and severe adverse effects. In contrast, pulmonary delivery allows a higher amount of drug to be delivered directly to the infection site and therefore a lower dose is required. This study aimed to develop porous and inhalable voriconazole dry powder with good lung deposition by spray freeze drying (SFD), using tert-butyl alcohol (TBA) as a co-solvent. A three-factor two-level full factorial design approach was used to investigate the effect of total solute concentration, drug content and co-solvent composition on the aerosol performance of the SFD powder. In general, the SFD voriconazole powder exhibited porous and spherical structure, and displayed crystalline characteristics. The analysis of factorial design indicated that voriconazole content was the most significant variable that could influence the aerosol performance of the SFD powders. The formulations that contained a high voriconazole content (40% w/w) and high TBA concentration in the feed solution (70% v/v) displayed the highest fine particle fraction of over 40% in the Next Generation Impactor study in which the powder was dispersed with a Breezhaler® at 100 L/min. In addition, the fine particle dose of the SFD powder showed a faster dissolution rate when compared to the unformulated voriconazole. Intratracheal administration of SFD voriconazole powder to mice resulted in a substantially higher drug concentration in the lungs when comparing to the group that received an equivalent dose of liquid voriconazole formulation intravenously, while a clinically relevant plasma drug concentration was maintained for at least two hours. Overall, an inhalable voriconazole dry powder formulation exhibiting good aerosol property and lung deposition was developed with clinical translation potential.

Development of an inhaled controlled release voriconazole dry powder formulation for the treatment of respiratory fungal infection

The present research aimed to develop and characterize a sustained release dry powder inhalable formulation of voriconazole (VRZ) for invasive pulmonary aspergillosis. The developed formulations were studied for their in vitro release profile, aerosol, and physicochemical properties as well as interactions with lung epithelia in terms of toxicity and transport/uptake. VRZ and VRZ loaded poly lactide microparticles (VLM) were prepared by aqueous/organic cosolvent and organic spray drying, respectively. Powders were characterized using laser diffraction, differential scanning calorimetry (DSC), X-ray powder diffraction (XRPD), dynamic vapor sorption (DVS), and electron microscopy. Aerosol performance was evaluated using an RS01 dry powder inhaler and in vitro cascade impaction. Uptake across Calu-3 lung epithelia was studied, using aerosol deposition of the powder onto cells cultured in an air interface configuration, and compared to dissolution using a conventional dialysis membrane. Additionally, toxicity of VRZ and VLM and the potential impact of transmembrane proteins on uptake were investigated. The particle size and the aerosol performance of spray-dried VRZ and VLM were suitable for inhalation purposes. VRZ exhibited a median volume diameter of 4.52 ± 0.07 μm while VLM exhibited 2.40 ± 0.05 μm. Spray-dried VRZ was crystalline and VLM amorphous as evaluated by DSC and XRPD, and both powders exhibited low moisture sorption between 0 and 90% RH (<1.2% w/w) by DVS. The fine particle fraction (FPF) (% aerosol <5 μm) for the VRZ was 20.86 ± 1.98% while the VLM showed significantly improved performance (p < 0.01) with an FPF of 43.56 ± 0.13%. Both VRZ and VLM were not cytotoxic over a VRZ concentration range of 1.2 nM to 30 μM, and the VLM particles exhibited a sustained release over 48 h after being deposited on the Calu-3 cell line or via conventional dialysis-based dissolution measurements. Lastly, VRZ exhibited polarized transport across epithelia with basal to apical transport being slower than apical to basal. Influx and efflux transports may also play a role as transport was altered in the presence of a number of inhibitors. This study has established an inhalable and sustained release powder of VRZ for targeting invasive pulmonary aspergillosis.

Inhaled anti-infective chemotherapy for respiratory tract infections: successes, challenges and the road ahead

One of the most common causes of illnesses in humans is from respiratory tract infections caused by bacterial, viral or fungal pathogens. Inhaled anti-infective drugs are crucial for the prophylaxis and treatment of respiratory tract infections. The benefit of anti-infective drug delivery via inhalation is that it affords delivery of sufficient therapeutic dosages directly to the primary site of infection, while minimizing the risks of systemic toxicity or avoiding potential suboptimal pharmacokinetics/pharmacodynamics associated with systemic drug exposure. This review provides an up-to-date treatise of approved and novel developmental inhaled anti-infective agents, with particular attention to effective strategies for their use, pulmonary pharmacokinetic properties and safety.

Development of voriconazole loaded large porous particles for inhalation delivery: effect of surface forces on aerosolisation performance, assessment of in vitro safety potential and uptake by macrophages

Inhalation delivery of voriconazole loaded large porous particles represent an effective and safe way to prolong pulmonary residence of voriconazole.