Manipulation of Spray-Drying Conditions to Develop an Inhalable Ivermectin Dry Powder

Inhalable spray-dried dry powders combining ivermectin and niclosamide to inhibit SARS-CoV-2 infection in vitro

SARS-CoV-2, the virus responsible for the COVID-19 pandemic, predominantly affects the respiratory tract, underscoring the need to develop antiviral agents in an inhalable formulation that can be delivered as prophylactic and/or therapeutic drugs directly to the infection site. Since the beginning of the pandemic, our group has been exploring the possibility of developing combinations of antiviral drugs that can be delivered as inhalable therapy, including combinations of remdesivir and ebselen or remdesivir and disulfiram prepared using a spray-drying technique. In this study, we used a similar spray-drying technique to develop inhalable dry powders combining the controversial drugs ivermectin and niclosamide, which have been reported to exhibit synergistic activity against SARS-CoV-2 in vitro. The combined dry powders were within the size range of 1-5 μm, amorphous in nature and displayed characteristic morphology after spray drying. The emitted dose (ED) of the spray-dried powders ranged from 68 to 83 %, whereas the fine particle fraction (FPF) ranged between 50 and 74 %. All the prepared dry powders remained stable under different humidity conditions (<15 % RH and 53 % RH). Interestingly, the optimized combinational dry powder of ivermectin and niclosamide showed an improved cytotoxic profile (CC50 value of 45.99 µM) and enhanced anti-SARS-CoV-2 activity in vitro (EC50 of 2.67 µM) compared to the single dry powders of ivermectin (CC50 = 20.25 µM and EC50 = 8.61 µM) and niclosamide (CC50 = 21.36 µM and EC50 = 5.28 µM). In summary, we developed a stable and inhalable combinational dry powder containing ivermectin and niclosamide, capable of inhibiting SARS-CoV-2 replication in vitro, demonstrating the potential to prepare dry powders that could be developed and delivered as inhalable antiviral drugs to prevent and/or treat SARS-CoV-2 or similar respiratory viruses.

Inhaled Dry Powder of Antiviral Agents: A Promising Approach to Treating Respiratory Viral Pathogens

Inhaled dry powder formulations of antiviral agents represent a novel and potentially transformative approach to managing respiratory viral infections. Traditional antiviral therapies in the form of tablets or capsules often face limitations in terms of therapeutic activity, systemic side effects, and delayed onset of action. Dry powder inhalers (DPIs) provide a targeted delivery system, ensuring the direct administration of antivirals to the infection site, the respiratory tract, which potentially enhance therapeutic efficacy and minimize systemic exposure. This review explores the current state of inhaled dry powder antiviral agents, their advantages over traditional routes, and specific formulations under development. We discuss the benefits of targeted delivery, such as improved drug deposition in the lungs and reduced side effects, alongside considerations related to the formulation preparation. In addition, we summarize the developed (published and marketed) inhaled dry powders of antiviral agents.

Evaluating the effect of sodium alginate and sodium carboxymethylcellulose on pulmonary delivery of levofloxacin spray-dried microparticles

BACKGROUND

Patients with cystic fibrosis commonly suffer from lung infections caused by Pseudomonas aeruginosa. Recently, the Levofloxacin (LVF) nebulizing solution (Quinsair®) has been prescribed for the antimicrobial management. The sustained-release (SR) dry powder formulation of LVF is a convenient alternative to Quinsair®. It has the potential to enhance patient convenience and decrease the likelihood of drug resistance over time.

OBJECTIVE

In this paper, we set forth to formulate and evaluate the potential application of sodium alginate (SA) and sodium carboxymethylcellulose (SCMC) for sustained pulmonary delivery of LVF.

METHODS

The spray-dried (SD) LVF microparticles were formulated using SCMC and SA along with L-leucine (Leu). The microparticles were analyzed in terms of particle size, morphology, x-ray diffraction (XRD), in-vitro drug release, and aerodynamic properties. Selected formulations were further proceeded to short-term stability test.

RESULTS

The polymer-containing samples displayed process yield of 33.31%-39.67%, mean entrapment efficiency of 89% and volume size within the range of 2-5 μm. All the hydrogel microparticles were amorphous and exhibited rounded morphology with surface indentations. Formulations with a drug-to-excipient ratio of 50:50 and higher, showed a 24-h SR. The aerodynamic parameters were fine particle fraction and emitted dose percentage ranging between 46.21%-60.6% and 66.67%-87.75%, respectively. The short-term stability test revealed that the formulation with a 50:50 drug-to-excipient ratio, containing SA, demonstrated better physical stability.

CONCLUSION

The selected formulation containing SA has the potential to extend the release duration. However, further enhancements are required to optimize its performance.

Development of a proliposomal pretomanid dry powder inhaler as a novel alternative approach for combating pulmonary tuberculosis

Multidrug-resistant tuberculosis (MDR-TB) and extensively drug-resistant tuberculosis (XDR-TB) continue as public health concerns. Inhaled drug therapy for TB has substantial benefits in combating the causal agent of TB (Mycobacterium tuberculosis). Pretomanid is a promising candidate in an optional combined regimen for XDR-TB. Pretomanid has demonstrated high potency against M. tuberculosis in both the active and latent phases. Conventional spray drying was used to formulate pretomanid as dry powder inhalers (DPIs) for deep lung delivery using a proliposomal system with a trehalose coarse excipient to enhance the drug solubility. Co-spray drying with L-leucine protected hygroscopic trehalose in formulations and improved powder aerosolization. Higher amounts of L-leucine (40-50 % w/w) resulted in the formation of mesoporous particles with high percentages of drug content and entrapment efficiency. The aerosolized powders demonstrated both geometric and median aerodynamic diameters < 5 µm with > 90 % emitted dose and > 50 % fine particle fraction. Upon reconstitution in simulated physiological fluid, the proliposomes completely converted to liposomes, exhibiting suitable particle sizes (130-300 nm) with stable colloids and improving drug solubility, leading to higher drug dissolution compared to the drug alone. Inhalable pretomanid showed higher antimycobacterial activity than pretomanid alone. The formulations were safe for all broncho-epithelial cell lines and alveolar macrophages, thus indicating their potential suitability for DPIs targeting pulmonary TB.

Modeling and evaluation of ivermectin release kinetics from 3D-printed tablets

Aim: This study focused on evaluating the influence of geometric dimensions on the drug release kinetics of 3D-printed tablets.Materials & methods: An ink based on Gelucire 50/13 was prepared to print ivermectin-loaded tablets. The ink was characterized physicochemically and tablet dissolution tests were carried out.Results: The results confirmed the suitability of the ink for 3D printing at a temperature >46°C. Changes in the crystallinity of ivermectin were observed without chemical interactions with the polymer. 3D printed tablets with varied proportional sizes showed dual behavior in their release profiles, while tablets with only thickness reduction exhibited zero-order kinetics.Conclusion: These findings highlight the versatility of 3D printing to create systems with specific and customized release profiles.

Design of Experiment (DoE) Approach for Developing Inhalable PLGA Microparticles Loaded with Clofazimine for Tuberculosis Treatment

Tuberculosis (TB) is an airborne bacterial infection caused by Mycobacterium tuberculosis (M. tb), resulting in approximately 1.3 million deaths in 2022 worldwide. Oral therapy with anti-TB drugs often fails to achieve therapeutic concentrations at the primary infection site (lungs). In this study, we developed a dry powder inhalable formulation (DPI) of clofazimine (CFZ) to provide localized drug delivery and minimize systemic adverse effects. Poly (lactic acid-co-glycolic acid) (PLGA) microparticles (MPs) containing CFZ were developed through a single emulsion solvent evaporation technique. Clofazimine microparticles (CFZ MPs) displayed entrapment efficiency and drug loading of 66.40 ± 2.22 %w/w and 33.06 ± 1.45 µg/mg, respectively. To facilitate pulmonary administration, MPs suspension was spray-dried to yield a dry powder formulation (CFZ SD MPs). Spray drying had no influence on particle size (~1 µm), zeta potential (-31.42 mV), and entrapment efficiency. Solid state analysis (PXRD and DSC) of CFZ SD MPs studies demonstrated encapsulation of the drug in the polymer. The drug release studies showed a sustained drug release. The optimized formulation exhibited excellent aerosolization properties, suggesting effective deposition in the deeper lung region. The in vitro antibacterial studies against H37Ra revealed improved (eight-fold) efficacy of spray-dried formulation in comparison to free drug. Hence, clofazimine dry powder formulation presents immense potential for the treatment of tuberculosis with localized pulmonary delivery and improved patient compliance.

Repurposing ebselen as an inhalable dry powder to treat respiratory tract infections

Respiratory tract infections (RTIs) are one of the leading causes of death globally, lately exacerbated by the increasing prevalence of antimicrobial resistance. While antimicrobial resistance could be overcome by developing new antimicrobial agents, the use of a safe repurposed agent having potent antimicrobial activity against various RTIs can be an efficient and cost-effective alternative to overcome the long and complex process of developing and testing new drugs. Ebselen, a synthetic organoselenium drug originally developed to treat noise-inducing hearing problems, has shown promising antimicrobial activity in vitro against several respiratory pathogens including viruses (e.g., SARS-CoV-2, influenza A virus) and bacteria (e.g., Mycobacterium tuberculosis, Streptococcus pneumoniae, and Staphylococcus aureus). Inhaled drug delivery is considered a promising approach for treating RTIs, as it can ensure effective drug concentrations at a lower dose, thereby minimizing the side effects that are often encountered by using oral or injectable drugs. In this study, we developed inhalable ebselen dry powder formulations using a spray-drying technique. The amino acids leucine, methionine, and tryptophan were incorporated with ebselen to enhance the yield and aerosolization of the dry powders. The amino acid-containing ebselen dry powders showed a better yield (37-56.4 %) than the amino acid-free formulation (30.9 %). All dry powders were crystalline in nature. The mass median aerodynamic diameter (MMAD) was less than 5 µm for amino acids containing dry powders (3-4 µm) and slightly higher (5.4 µm) for amino acid free dry powder indicating their suitability for inhalation. The aerosol performance was higher when amino acids were used, and the leucine-containing ebselen dry powder showed the highest emitted dose (84 %) and fine particle fraction (68 %). All amino acid formulations had similar cytotoxicity as raw ebselen, tested in respiratory cell line (A549 cells), with half-maximal inhibitory concentrations (IC50) between 100 and 250 μg/mL. Raw ebselen and amino acid-containing dry powders showed similar potent antibacterial activity against the Gram-positive bacteria S. aureus and S. pneumoniae with minimum inhibitory concentrations of 0.31 μg/mL and 0.16 μg/mL, respectively. On the other hand, raw ebselen and the formulations showed limited antimicrobial activity against the Gram-negative pathogens Pseudomonas aeruginosa and Klebsiella pneumoniae. In summary, in this study we were able to develop amino-acid-containing inhalable dry powders of ebselen that could be used against different respiratory pathogens, especially Gram-positive bacteria, which could ensure more drug deposition in the respiratory tract, including the lungs. DPIs are generally used to treat lung (lower respiratory tract) diseases. However, DPIs can also be used to treat both upper and lower RTIs. The deposition of the dry powder in the respiratory tract is dependent on its physicochemical properties and this properties can be modulated to target the intended site of infection (upper and/or lower respiratory tract). Further studies will allow the development of similar formulations of individual and/or combination of antimicrobials that could be used to inhibit a number of respiratory pathogens.

Inhalable dry powder containing remdesivir and disulfiram: Preparation and in vitro characterization

The respiratory tract, as the first and most afflicted target of many viruses such as SARS-CoV-2, seems to be the logical choice for delivering antiviral agents against this and other respiratory viruses. A combination of remdesivir and disulfiram, targeting two different steps in the viral replication cycle, has showed synergistic activity against SARS-CoV-2 in-vitro. In this study, we have developed an inhalable dry powder containing a combination of remdesivir and disulfiram utilizing the spray-drying technique, with the final goal of delivering this drug combination to the respiratory tract. The prepared dry powders were spherical, and crystalline. The particle size was between 1 and 5 μm indicating their suitability for inhalation. The spray-dried combinational dry powder containing remdesivir and disulfiram (RDSD) showed a higher emitted dose (ED) of >88% than single dry powder of remdesivir (RSD) (∼72%) and disulfiram (DSD) (∼84%), with a fine particle fraction (FPF) of ∼55%. Addition of L-leucine to RDSD showed >60% FPF with a similar ED. The in vitro aerosolization was not significantly affected after the stability study conducted at different humidity conditions. Interestingly, the single (RSD and DSD) and combined (RDSD) spray-dried powders showed limited cellular toxicity (CC50 values from 39.4 to >100 µM), while maintaining their anti-SARS-CoV-2 in vitro (EC50 values from 4.43 to 6.63 µM). In a summary, a combinational dry powder formulation containing remdesivir and disulfiram suitable for inhalation was developed by spray-drying technique which showed high cell viability in the respiratory cell line (Calu-3 cells) retaining their anti-SARS-CoV-2 property. In the future, in vivo studies will test the ability of these formulations to inhibit SARS-CoV-2 which is essential for clinical translation.

Spray-Dried Inhalable Microparticles Combining Remdesivir and Ebselen against SARS-CoV-2 Infection

There is a continuous effort to develop efficient treatments for coronavirus disease 2019 (COVID-19) and other viral respiratory diseases. Among the different strategies, inhaled treatment is considered one of the most logical and efficient approaches to treating COVID-19, as the causative "SARS-CoV-2 virus RNA" predominantly infects the respiratory tract. COVID-19 treatments initially relied on repurposed drugs, with a few additional strategies developed during the last two years, and all of them are based on monotherapy. However, drug combinations have been found to be more effective than monotherapy in other viral diseases such as HIV, influenza, and hepatitis C virus. In the case of SARS-CoV-2 infection, in vitro studies have shown synergistic antiviral activity combining remdesivir with ebselen, an organoselenium compound. Therefore, these drug combinations could ensure better therapeutic outcomes than the individual agents. In this study, we developed a dry powder formulation containing remdesivir and ebselen using a spray-drying technique and used L-leucine as an aerosolization enhancer. The prepared dry powders were spherical and crystalline, with a mean particle size between 1 and 3 µm, indicating their suitability for inhalation. The emitted dose (ED) and fine particle fraction (FPF) of remdesivir- and ebselen-containing dry powders were ~80% and ~57% when prepared without L-leucine. The ED as well as the FPF significantly increased with values of >86% and >67%, respectively, when L-leucine was incorporated. More importantly, the single and combinational dry powder of remdesivir and ebselen showed minimal cytotoxicity (CC50 > 100 μM) in Calu-3 cells, retaining their anti-SARS-CoV-2 properties (EC50 2.77 to 18.64 μM). In summary, we developed an inhalable dry powder combination of remdesivir and ebselen using a spray-drying technique. The spray-dried inhalable microparticles retained their limited cytotoxicity and specific antiviral properties. Future in vivo studies are needed to verify the potential use of these remdesivir/ebselen combinational spray-dried inhalable microparticles to block the SARS-CoV-2 replication in the respiratory tract.

Development of Large Hollow Particles for Pulmonary Delivery of Cyclosporine A

The purpose of this study was to prepare large hollow particles (LHPs) by spray drying for pulmonary delivery of cyclosporine A (CsA), using L-Leucine (LEU) and hydroxypropyl methylcellulose (HPMC) as excipients and ammonium bicarbonate (AB) as a porogen. The prepared LHPs were spherical particles composed of both CsA and LEU on the surface and HPMC on the inner layer. The formulation of CsA-LEU-0.8HPMC-AB as typical LHPs showed excellent in vitro aerodynamic performance with a minimum mass median aerodynamic diameter (MMAD) of 1.15 μm. The solubility of CsA-LEU-0.8HPMC-AB was about 5.5-fold higher than that of raw CsA, and the dissolution of CsA-LEU-0.8HPMC-AB suggested that the drug was released within 1 h. The cell viability of the A549 cell line showed that CsA-LEU-0.8HPMC-AB was safe for delivering CsA to the lungs. In addition, inhalation administration of CsA-LEU-0.8HPMC-AB with the Cmax and AUC0-∞ increasing by about 2-fold and 2.8-fold compared with the oral administration of Neoral® could achieve therapeutic drug concentrations with lower systemic exposure and significantly improve the in vivo bioavailability of CsA. From these findings, the LHPs, with the advantage of avoiding alveolar macrophage clearance, could be a viable choice for delivering CsA by inhalation administration relative to oral administration.

Dissolution and Absorption of Inhaled Drug Particles in the Lungs

Dry powder inhalation therapy has been effective in treating localized lung diseases such asthma, chronic obstructive pulmonary diseases (COPD), cystic fibrosis and lung infections. In vitro characterization of dry powder formulations includes the determination of physicochemical nature and aerosol performance of powder particles. The relationship between particle properties (size, shape, surface morphology, porosity, solid state nature, and surface hydrophobicity) and aerosol performance of an inhalable dry powder formulation has been well established. However, unlike oral formulations, there is no standard dissolution method for evaluating the dissolution behavior of the inhalable dry powder particles in the lungs. This review focuses on various dissolution systems and absorption models, which have been developed to evaluate dry powder formulations. It covers a summary of airway epithelium, hurdles to developing an in vitro dissolution method for the inhaled dry powder particles, fine particle dose collection methods, various in vitro dissolution testing methods developed for dry powder particles, and models commonly used to study absorption of inhaled drug.

Amorphicity and Aerosolization of Soluplus-Based Inhalable Spray Dried Powders

Soluplus is a polymer that has been explored to prepare nanocomposites for pulmonary drug delivery and is non-toxic. However, its aerosolization attributes when spray-dried have not been investigated. Hence, this work aimed to investigate the aerosol performance of soluplus-based spray-dried powders. In addition, the potential use of leucine to improve the aerosolization of such particles was also investigated by including leucine at 10 or 20% w/w. 4% w/w salbutamol was used as a model drug in all the formulations primarily to aid quantification during aerosolization evaluation and for assessing the interaction between the drug and soluplus using infrared spectroscopy with the multivariate analysis approach of principal component analysis (PCA). Three formulations (4% salbutamol/96% soluplus, 4% salbutamol/86% soluplus/10% leucine, 4% salbutamol/76% soluplus/20% leucine) were prepared. The formulations were characterized in terms of solid-state, water content, particle size/morphology, and aerosolization. Similarly, two additional formulations (14% salbutamol/86% soluplus and 24% salbutamol/76% soluplus) were prepared to assess potential non-covalent interactions between salbutamol and soluplus. The formulations with only salbutamol and soluplus were amorphous, as evident from X-ray diffraction. Leucine was crystalline in the formulations. All the spray-dried formulations were irregular spheres with surface corrugation. The 96% soluplus powder showed an emitted fraction (EF) and fine particles fraction (FPF) of 91.9 and 49.8%, respectively. The inclusion of leucine at 10% did not increase the EF; however, an increase in FPF (69.7%) was achieved with 20% leucine. PCA of the infrared spectra suggested potential non-covalent interactions between salbutamol and soluplus. It hinted at the potential involvement of ketone groups of the excipient. This study concludes that soluplus-based spray-dried powder with or without leucine can potentially be utilized for pulmonary drug delivery. In addition, PCA can effectively be utilized in assessing interactions and overcoming limitations associated with visual assessment of the spectra of such formulations.