Spray freeze drying of small nucleic acids as inhaled powder for pulmonary delivery

Inhalable Dry Powders for Lung mRNA Delivery

Despite great promise, application of mRNA therapeutics in the lung has proven challenging. Many groups have reported success instilling liquid mRNA formulations in animal models, but direct intratracheal administration of large liquid quantities to the human lung presents significant safety and distribution concerns. To accomplish safe and effective mRNA delivery to the lung, formulations must be prepared for dosing via inhalation. An inhaled mRNA delivery system for the lung must be both robust enough to survive inhalation conditions and potent enough to deliver mRNA upon reaching the lung. In this work dry powder lipid nanoparticle formulations are developed, using spray-freeze-drying, to produce stable, biologically active, inhalable dry powders for mRNA delivery. The final powders have suitable aerosolization properties, with mean mass aerodynamic diameter (MMAD) of 3-4 microns, and fine particle fraction (FPF) ≈40%, allowing for efficient mRNA delivery to the deep lung following inhalation. Importantly, the formulations developed here are suitable for use with different ionizable lipids. Four different ionizable lipid-based formulations are evaluated as powders, and all exhibit in vivo pulmonary mRNA delivery equal to that of instilled liquid formulations. These results lay promising groundwork for the eventual development of an inhalable mRNA dry powder therapeutic.

Particulate atomisation design methods for the development and engineering of advanced drug delivery systems: A review

The role and opportunities presented by particulate technologies (due to novel processing methods and advanced materials) have multiplied over the last few decades, leading to promising and ideal properties for drug delivery. For example, the dissolution and bioavailability of poorly soluble drug substances and achieving site- specific drug delivery with a desired release profile are crucial aspects of forming (to some extent) state-of-the-art platforms. Atomisation techniques are intended to achieve efficient control over particle size, improved processing time, improved drug loading efficiency, and the opportunity to encapsulate a broad range of viable yet sensitive therapeutic moieties. Particulate engineering through atomization is accomplished by employing various mechanisms such as air, no air, centrifugal, electrohydrodynamic, acoustic, and supercritical fluid driven processes. These driving forces overcome capillary stresses (e.g., liquid viscosity, surface tension) and transform formulation media (liquid) into fine droplets. More frequently, solvent removal, multiple methods are included to reduce the final size distribution. Nevertheless, a thorough understanding of fluid mechanics, thermodynamics, heat, and mass transfer is imperative to appreciate and predict outputs in real time. More so, in recent years, several advancements have been introduced to improve such processes through complex particle design coupled with quality by-design (QbD) yielding optimal particulate geometry in a predictable manner. Despite these valuable and numerous advancements, atomisation techniques face difficulty scaling up from laboratory scales to manufacturing industry scales. This review details the various atomisation techniques (from design to mechanism) along with examples of drug delivery systems developed. In addition, future perspectives and bottlenecks are provided while highlighting current and selected seminal developments in the field.

Spray freeze dried cannabidiol with dipalmitoylphosphatidylcholine (DPPC) for inhalation and solubility enhancement

Pulmonary delivery is an efficient route of administration to deliver cannabidiol (CBD) due to the high bioavailability and fast onset of action. The major formulation challenge is the poor aqueous solubility of CBD. This study aimed to produce inhalable CBD powders with enhanced solubility and characterise their solid-state properties. CBD was spray freeze dried with mannitol or trehalose dihydrate with and without dipalmitoylphosphatidylcholine (DPPC). All four powders had acceptable yields at > 70 % with porous and spherical particles. The two crystalline mannitol powders contained less residual solvent than both amorphous trehalose ones. The addition of DPPC did not affect the crystallinity and residual solvent level of the powders. Instead, DPPC made the particles more porous, decreased the particle size from 19-23 µm to 11-13 µm, and increased CBD solubility from 0.36 µg/mL to over 2 µg/mL. The two DPPC powders were dispersed from a low resistance RS01 inhaler, showing acceptable aerosol performance with emitted fractions at 91-93 % and fine particle fractions < 5 µm at 34-43 %. These formulations can be used as a platform to deliver CBD and other cannabinoids by inhalation.

Modern trends in the formulation of microparticles for lung delivery using porogens: methods, principles and examples

Inhalation drug administration is increasingly used for local pharmacotherapy of lung disorders and as an alternative route for systemic drug delivery. Modern inhalation powder systems aim to target drug deposition in the required site of action. Large porous particles (LPP), characterized by an aerodynamic diameter over 5 μm, density below 0.4 g/cm3, and the ability to avoid protective lung mechanisms, come to the forefront of the research. They are mostly prepared by spray techniques such as spray drying or lyophilization using pore-forming substances (porogens). These substances could be gaseous, solid, or liquid, and their selection depends on their polarity, solubility, and mutual compatibility with the carrier material and the drug. According to the pores-forming mechanism, porogens can be divided into groups, such as osmogens, extractable porogens, and porogens developing gases during decomposition. This review characterizes modern trends in the formulation of solid microparticles for lung delivery; describes the mechanisms of action of the most often used porogens, discusses their applicability in various formulation methods, emphasizes spray techniques; and documents discussed topics by examples from experimental studies.

Recent Progress in Nucleic Acid Pulmonary Delivery toward Overcoming Physiological Barriers and Improving Transfection Efficiency

Pulmonary delivery of therapeutic agents has been considered the desirable administration route for local lung disease treatment. As the latest generation of therapeutic agents, nucleic acid has been gradually developed as gene therapy for local diseases such as asthma, chronic obstructive pulmonary diseases, and lung fibrosis. The features of nucleic acid, specific physiological structure, and pathophysiological barriers of the respiratory tract have strongly affected the delivery efficiency and pulmonary bioavailability of nucleic acid, directly related to the treatment outcomes. The development of pharmaceutics and material science provides the potential for highly effective pulmonary medicine delivery. In this review, the key factors and barriers are first introduced that affect the pulmonary delivery and bioavailability of nucleic acids. The advanced inhaled materials for nucleic acid delivery are further summarized. The recent progress of platform designs for improving the pulmonary delivery efficiency of nucleic acids and their therapeutic outcomes have been systematically analyzed, with the application and the perspectives of advanced vectors for pulmonary gene delivery.

Spray-freeze-drying as emerging and substantial quality enhancement technique in food industry

Spray freeze drying is an emerging technology in the food industry with numerous applications. Its ability to preserve food quality, maintain nutritional value, and reduce bulk make it an attractive option to food manufacturers. Spray freeze drying can be used to reduce the water content of foods while preserving the shelf life and nutritional value. Spray freeze-drying of food products is a process that involves atomizing food into small droplets and then flash-freezing them. The frozen droplets are then placed in a vacuum chamber and heated, causing the liquid to evaporate and the solid particles to become a dry powder. Spray freeze drying has become a valuable tool for the food industry through its ability to process a wide range of food products. This review's prime focus is understanding spray freeze-dried approaches and emphasizing their applicability in various products.

Engineering Inhalable Therapeutic Particles: Conventional and Emerging Approaches

Respirable particles are integral to effective inhalable therapeutic ingredient delivery, demanding precise engineering for optimal lung deposition and therapeutic efficacy. This review describes different physicochemical properties and their role in determining the aerodynamic performance and therapeutic efficacy of dry powder formulations. Furthermore, advances in top-down and bottom-up techniques in particle preparation, highlighting their roles in tailoring particle properties and optimizing therapeutic outcomes, are also presented. Practices adopted for particle engineering during the past 100 years indicate a significant transition in research and commercial interest in the strategies used, with several innovative concepts coming into play in the past decade. Accordingly, this article highlights futuristic particle engineering approaches such as electrospraying, inkjet printing, thin film freeze drying, and supercritical processes, including their prospects and associated challenges. With such technologies, it is possible to reshape inhaled therapeutic ingredient delivery, optimizing therapeutic benefits and improving the quality of life for patients with respiratory diseases and beyond.

Practical Considerations for Next-Generation Adjuvant Development and Translation

Over the last several years, there has been increased interest from academia and the pharmaceutical/biotech industry in the development of vaccine adjuvants for new and emerging vaccine modalities. Despite this, vaccine adjuvant development still has some of the longest timelines in the pharmaceutical space, from discovery to clinical approval. The reasons for this are manyfold and range from complexities in translation from animal to human models, concerns about safety or reactogenicity, to challenges in sourcing the necessary raw materials at scale. In this review, we will describe the current state of the art for many adjuvant technologies and how they should be approached or applied in the development of new vaccine products. We postulate that there are many factors to be considered and tools to be applied earlier on in the vaccine development pipeline to improve the likelihood of clinical success. These recommendations may require a modified approach to some of the common practices in new product development but would result in more accessible and practical adjuvant-containing products.

An Overview of the Stability and Delivery Challenges of Commercial Nucleic Acid Therapeutics

Nucleic acid (NA)-based biopharmaceuticals have emerged as promising therapeutic modalities. NA therapeutics are a diverse class of RNA and DNA and include antisense oligonucleotides, siRNA, miRNA, mRNA, small activating RNA, and gene therapies. Meanwhile, NA therapeutics have posed significant stability and delivery challenges and are expensive. This article discusses the challenges and opportunities for achieving stable formulations of NAs with novel drug delivery systems (DDSs). Here we review the current progress in the stability issues and the significance of novel DDSs associated with NA-based biopharmaceuticals, as well as mRNA vaccines. We also highlight the European Medicines Agency (EMA) and US Food and Drug Administration (FDA)-approved NA-based therapeutics with their formulation profiles. NA therapeutics could impact future markets if the remaining challenges and requirements are addressed. Regardless of the limited information available for NA therapeutics, reviewing and collating the relevant facts and figures generates a precious resource for formulation experts familiar with the NA therapeutics' stability profile, their delivery challenges, and regulatory acceptance.

Formulation, Device, and Clinical Factors Influencing the Targeted Delivery of COVID-19 Vaccines to the Lungs

The COVID-19 pandemic has proven to be an unprecedented health crisis in the human history with more than 5 million deaths worldwide caused to the SARS-CoV-2 and its variants ( https://www.who.int/emergencies/diseases/novel-coronavirus-2019 ). The currently authorized lipid nanoparticle (LNP)-encapsulated mRNA vaccines have been shown to have more than 90% vaccine efficacy at preventing COVID-19 illness (Baden et al. New England J Med 384(5):403-416, 2021; Thomas et al., 2021). In addition to vaccines, other small molecules belonging to the class of anti-viral and anti-inflammatory compounds have also been prescribed to reduce the viral proliferation and the associated cytokine storm. These anti-viral and anti-inflammatory compounds have also been shown to be effective in reducing COVID-19 exacerbations especially in reducing the host inflammatory response to SARS-CoV-2. However, all of the currently FDA-authorized vaccines for COVID-19 are meant for intramuscular injection directly into the systemic circulation. Also, most of the small molecules investigated for their anti-COVID-19 efficacy have also been explored using the intravenous route with a few of them explored for the inhalation route (Ramakrishnan et al. Lancet Respir Med 9:763-772, 2021; Horby et al. N Engl J Med 384(8):693-704, 2021). The fact that the SARS-CoV-2 enters the human body mainly via the nasal and airway route resulting in the lungs being the primary organs of infection as characterized by acute respiratory distress syndrome (ARDS)-mediated cytokine storm in the alveolar region has made the inhalation route gain significant attention for the purposes of targeting both vaccines and small molecules to the lungs (Mitchell et al., J Aerosol Med Pulm Drug Deliv 33(4):235-8, 2020). While there have been many studies reporting the safety and efficacy of targeting various therapeutics to the lungs to treat COVID-19, there is still a need to match the choice of inhalation formulation and the delivery device platform itself with the patient-related factors like breathing pattern and respiratory rate as seen in a clinical setting. In that perspective, this review aims to describe the various formulation and patient-related clinical factors that can play an important role in the judicious choice of the inhalation delivery platforms or devices for the development of inhaled COVID-19 vaccines.

Advancements in the Design and Development of Dry Powder Inhalers and Potential Implications for Generic Development

Dry powder inhalers (DPIs) are drug-device combination products where the complexity of the formulation, its interaction with the device, and input from users play important roles in the drug delivery. As the landscape of DPI products advances with new powder formulations and novel device designs, understanding how these advancements impact performance can aid in developing generics that are therapeutically equivalent to the reference listed drug (RLD) products. This review details the current understanding of the formulation and device related principles driving DPI performance, past and present research efforts to characterize these performance factors, and the implications that advances in formulation and device design may present for evaluating bioequivalence (BE) for generic development.

Pulmonary Delivery of Emerging Antibacterials for Bacterial Lung Infections Treatment

Bacterial infections in the respiratory tract are considered as one of the major challenges to the public health worldwide. Pulmonary delivery is an attractive approach in the management of bacterial respiratory infections with a few inhaled antibiotics approved. However, with the rapid emergence of antibiotic-resistant bacteria, it is necessary to develop new/alternative inhaled antibacterial agents in the post-antibiotic era. A pipeline of novel biological antibacterial agents, including antimicrobial peptides, RNAi therapeutics, and bacteriophages, has emerged to combat bacterial infections with excellent performance. In this review, the causal effects of bacterial infections on the related pulmonary infectious diseases will be firstly introduced. This is followed by an overview on the development of emerging antibacterial therapeutics for managing lung bacterial infections through nebulization/inhalation of dried powders. The obstacles and underlying proposals regarding their clinical transformation are also discussed to seek insights for further development. Research on inhaled therapy of these emerging antibacterials are still in the infancy, but the promising progress warrants further attention.

Aggregation of Lactoferrin Caused by Droplet Atomization Process via a Two-Fluid Nozzle: The Detrimental Effect of Air-Water Interfaces

Biological macromolecules, especially therapeutic proteins, are delicate and highly sensitive to denaturation from stresses encountered during the manufacture of dosage forms. Thin-film freeze-drying (TFFD) and spray freeze-drying (SFD) are two processes used to convert liquid forms of protein into dry powders. In the production of inhalable dry powders that contain proteins, these potential stressors fall into three categories based on their occurrence during the primary steps of the process: (1) droplet formation (e.g., the mechanism of droplet formation, including spray atomization), (2) freezing, and (3) frozen water removal (e.g., sublimation). This study compares the droplet formation mechanism used in TFFD and SFD by investigating the effects of spraying on the stability of proteins, using lactoferrin as a model. This study considers various perspectives on the denaturation (e.g., conformation) of lactoferrin after subjecting the protein solution to the atomization process using a pneumatic two-fluid nozzle (employed in SFD) or a low-shear drop application through the nozzle. The surface activity of lactoferrin was examined to explore the interfacial adsorption tendency, diffusion, and denaturation process. Subsequently, this study also investigates the secondary and tertiary structure of lactoferrin and the quantification of monomers, oligomers, and, ultimately, aggregates. The spraying process affected the tertiary structure more negatively than the tightly woven secondary structure, resulting in the peak position corresponding to the tryptophan (Trp) residues red-shifting by 1.5 nm. This conformational change can either (a) be reversed at low concentrations via relaxation or (b) proceed to form irreversible aggregates at higher concentrations. Interestingly, when the sample was allowed to progress into micrometer-sized aggregates, such a dramatic change was not detected using methods such as size-exclusion chromatography, polyacrylamide gel electrophoresis, and dynamic light scattering at 173°. A more complete understanding of the heterogeneous protein sample was achieved only through a combination of 173 and 13° backward and forward scattering, a combination of derived count rate measurements, and microflow imaging (MFI). After studying the impact of droplet formation mechanisms on aggregation tendency of lactoferrin, we further investigated two additional model proteins with different surface activity: bovine IgG (serving as a non surface-active negative reference), and β-galactosidase (another surface-active protein). The results corroborated the lactoferrin findings that spray-atomization-related stress-induced protein aggregation was much more pronounced for proteins that are surface active (lactoferrin and β-galactosidase), but it was minimal for non-surface-active protein (bovine IgG). Finally, compared to the low-shear dripping used in the TFFD process, lactoferrin underwent a relatively fast conformational change upon exposure to the high air-water interface of the two-fluid atomization nozzle used in the SFD process as compared to the low shear dripping used in the TFFD process. The interfacial-induced denaturation that occurred during spraying was governed primarily by the size of the atomized droplets, regardless of the duration of exposure to air. The percentage of denatured protein population and associated activity loss, in the case of β-galactosidase, was determined to range from 2 to 10% depending on the air-flow rate of the spraying process.

Dual targeting powder formulation of antiviral agent for customizable nasal and lung deposition profile through single intranasal administration

Unpredictable outbreaks due to respiratory viral infections emphasize the need for new drug delivery strategies to the entire respiratory tract. As viral attack is not limited to a specific anatomic region, antiviral therapy that targets both the upper and lower respiratory tract would be most effective. This study aimed to formulate tamibarotene, a retinoid derivative previously reported to display broad-spectrum antiviral activity against influenza and severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), as a novel dual particle size powder formulation that targets both the nasal cavity and the lung by a single route of intranasal administration. Spray freeze drying (SFD) and spray drying (SD) techniques were employed to prepare tamibarotene powder formulations, and cyclodextrin was used as the sole excipient to enhance drug solubility. With the employment of appropriate atomizing nozzles, particles of size above 10 μm and below 5 μm could be produced for nasal and lung deposition, respectively. The aerosol performance of the powder was evaluated using Next Generation Impactor (NGI) coupled with a glass expansion chamber and the powder was dispersed with a nasal powder device. By blending powder of two different particle sizes, a single powder formulation with dual aerosol deposition characteristic in both the nasal and pulmonary regions was produced. The aerosol deposition fractions in the nasal cavity and pulmonary region could be modulated by varying the powder mixing ratio. All dry powder formulations exhibited spherical structures, amorphous characteristics and improved dissolution profile as compared to the unformulated tamibarotene. Overall, a novel dual targeting powder formulation of tamibarotene exhibiting customizable aerosol deposition profile was developed. This exceptional formulation strategy can be adopted to deliver other antimicrobial agents to the upper and lower airways for the prevention and treatment of human respiratory infections.

Advancements in Particle Engineering for Inhalation Delivery of Small Molecules and Biotherapeutics

Dry powder inhalation formulations have become increasingly popular for local and systemic delivery of small molecules and biotherapeutics. Powder formulations provide distinct advantages over liquid formulations such as elimination of cold chain due to room temperature stability, improved portability, and the potential for increasing patient adherence. To become a viable product, it is essential to develop formulations that are stable (physically, chemically and/or biologically) and inhalable over the shelf-life. Physical particulate properties such as particle size, morphology and density, as well as chemical properties can significantly impact aerosol performance of the powder. This review will cover these critical attributes that can be engineered to enhance the dispersibility of inhalation powder formulations. Challenges in particle engineering for biotherapeutics will be assessed, followed by formulation strategies for overcoming the hurdles. Finally, the review will discuss recent examples of successful dry powder biotherapeutic formulations for inhalation delivery that have been clinically assessed.

Spray Freeze-Drying for inhalation application: Process and Formulation Variables

High porous particles with specific aerodynamic properties were processed by the spray freeze-drying (SFD) method. Comprehensive knowledge about all aspects of the SFD method is required for particle engineering of various pharmaceutical products with good flow properties. In this review, different types of the SFD method, the most frequently employed excipients, properties of particles prepared by this method, and most recent approaches concerning SFD are summarized. Generally, this technique can prepare spherical-shaped particles with a highly porous interior structure, responsible for the very low density of powders. Increasing the solubility of spray freeze-dried formulations achieves the desired efficacy. Also, due to the high efficiency of SFD, by determining the different features of this method and optimizing the process by model-based studies, desirable results for various inhaled products can be achieved and significant progress can be made in the field of pulmonary drug delivery.

Nanoparticles as an effective drug delivery system in COVID-19

BACKGROUND

The global healthcare sector has been dealing with a situation known as a novel severe acute respiratory syndrome (SARS-CoV-2) since the end of 2019. Covid-19 is an acronym for Covid-19 (Coronavirus Disease- 2019). It causes a respiratory infection that includes cold, sneezing and coughing, and pneumonia. In the case of an animal, it causes diarrhea and upper respiratory diseases. Covid-19 transmitted human to human via airborne droplets. First Covid-19 emerged in Wuhan market China and it spread rapidly throughout the World. As we know nanoparticles are a novel drug delivery system. They have various advantageous effects like increasing the efficacy of the drug, safety, etc. In this review, we study about the nanoparticles and summarize how it is effective during drug delivery system in Covid-19. Chitosan is a much focused biopolymeric nanoparticle. It delivers drugs to the specific target site. In a recent health crisis, chitosan nanoparticles are one of the ways to release drugs of Covid-19, and specifically in the lungs of the affected patients. We studied and extracted our data from various research papers, review papers, and some other articles.

OBJECTIVE

The main goal is to study the nanoparticles and their future aspects which is an effective drug delivery system in Covid-19.

METHODS

The bibliographic search was done through a systematic search. The terms "Nanoparticles", "Covid-19 ", "Drug delivery" etc. were used to search the databases/search engines like "Google Scholar", "NCBI", "PubMed", "Science Direct" etc. These databases and search engines used here perform the limited criteria of search to conduct a systematic literature survey for the study and report writing. All the text from the articles and research papers were studied and analyzed. The various articles and research papers were used in writing this report and all of which are mentioned in the reference section of this report.

CONCLUSION

Our current studies reveal that nanoparticles may prove very helpful in the delivery of drugs for Covid-19 treatment. Many cases showed that patients, where drugs are delivered with the help of nanoparticles, produced very few side effects.

Efficient Inhibition of SARS-CoV-2 Using Chimeric Antisense Oligonucleotides through RNase L Activation*

There is an urgent need to develop antiviral drugs and alleviate the current COVID-19 pandemic. Herein we report the design and construction of chimeric oligonucleotides comprising a 2'-OMe-modified antisense oligonucleotide and a 5'-phosphorylated 2'-5' poly(A)₄ (4A_2-5 ) to degrade envelope and spike RNAs of SARS-CoV-2. The oligonucleotide was used for searching and recognizing target viral RNA sequence, and the conjugated 4A_2-5 was used for guided RNase L activation to sequence-specifically degrade viral RNAs. Since RNase L can potently cleave single-stranded RNA during innate antiviral response, degradation efficiencies with these chimeras were twice as much as those with only antisense oligonucleotides for both SARS-CoV-2 RNA targets. In pseudovirus infection models, chimera-S4 achieved potent and broad-spectrum inhibition of SARS-CoV-2 and its N501Y and/or ΔH69/ΔV70 mutants, indicating a promising antiviral agent based on the nucleic acid-hydrolysis targeting chimera (NATAC) strategy.

Particle engineering principles and technologies for pharmaceutical biologics

The global market of pharmaceutical biologics has expanded significantly during the last few decades. Currently, pharmaceutical biologic products constitute an indispensable part of the modern medicines. Most pharmaceutical biologic products are injections either in the forms of solutions or lyophilized powders because of their low oral bioavailability. There are certain pharmaceutical biologic entities formulated into particulate delivery systems for the administration via non-invasive routes or to achieve prolonged pharmaceutical actions to reduce the frequency of injections. It has been well documented that the design of nano- and microparticles via various particle engineering technologies could render pharmaceutical biologics with certain benefits including improved stability, enhanced intracellular uptake, prolonged pharmacological effect, enhanced bioavailability, reduced side effects, and improved patient compliance. Herein, we review the principles of the particle engineering technologies based on bottom-up approach and present the important formulation and process parameters that influence the critical quality attributes with some mathematical models. Subsequently, various nano- and microparticle engineering technologies used to formulate or process pharmaceutical biologic entities are reviewed. Lastly, an array of commercialized products of pharmaceutical biologics accomplished based on various particle engineering technologies are presented and the challenges in the development of particulate delivery systems for pharmaceutical biologics are discussed.

A Pathway From Porous Particle Technology Toward Tailoring Aerogels for Pulmonary Drug Administration

Pulmonary drug delivery has recognized benefits for both local and systemic treatments. Dry powder inhalers (DPIs) are convenient, portable and environmentally friendly devices, becoming an optimal choice for patients. The tailoring of novel formulations for DPIs, namely in the form of porous particles, is stimulating in the pharmaceutical research area to improve delivery efficiency. Suitable powder technological approaches are being sought to design such formulations. Namely, aerogel powders are nanostructured porous particles with particularly attractive properties (large surface area, excellent aerodynamic properties and high fluid uptake capacity) for these purposes. In this review, the most recent development on powder technologies used for the processing of particulate porous carriers are described via updated examples and critically discussed. A special focus will be devoted to the most recent advances and uses of aerogel technology to obtain porous particles with advanced performance in pulmonary delivery.

The effect of ethanol on the habit and in vitro aerodynamic results of dry powder inhalation formulations containing ciprofloxacin hydrochloride

In the case of dry powder inhalation systems (DPIs), the development of carrier-free formulations has gained increased attention. Thereby, spray-drying is a promising technology and is widely used to produce carrier-free DPIs. Numerous works have been published about the co-spray-drying of active ingredients with various solid excipients and their effect on the physicochemical characteristics and aerodynamic properties of the formulations. However, only a few studies have been reported about the role of the solvents used in the stock solutions of spray-dried formulations. In the present work, DPI microcomposites containing ciprofloxacin hydrochloride were prepared by spray-drying in the presence of different ethanol concentrations. The work expresses the roughness, depth and width of the dimples for particle size as a novel calculation possibility, and as a correlation between the MMAD/D_0.5 ratio and correlating it with cohesion work, these new terms and correlations have not been published – to the best of our knowledge – which has resulted in gap-filling findings. As a result, different proportions of solvent mixtures could be interpreted and placed in a new perspective, in which the influence of different concentrations of ethanol on the habit of the DPI formulations, and thus on in vitro aerodynamic results. Based on these, it became clear why we obtained the best in vitro aerodynamic results for DPI formulation containing 30% ethanol in the stock solution.

Dry powder pharmaceutical biologics for inhalation therapy

Therapeutic biologics such as genes, peptides, proteins, virus and cells provide clinical benefits and are becoming increasingly important tools in respiratory medicine. Pulmonary delivery of therapeutic biologics enables the potential for safe and effective treatment option for respiratory diseases due to high bioavailability while minimizing absorption into the systemic circulation, reducing off-target toxicity to other organs. Development of inhalable powder formulation requires stabilization of complex biological materials, and each type of biologics may present unique challenges and require different formulation strategy combined with manufacture process to ensure biological and physical stabilities during production and over shelf-life. This review examines key formulation strategies for stabilizing proteins, nucleic acids, virus (bacteriophages) and bacterial cells in inhalable powders. It also covers characterization methods used to assess physicochemical properties and aerosol performance of the powders, biological activity and structural integrity of the biologics, and chemical analysis at the nanoscale. Furthermore, the review includes manufacture technologies which are based on lyophilization and spray-drying as they have been applied to manufacture Food and Drug Administration (FDA)-approved protein powders. In perspective, formulation and manufacture of inhalable powders for biologic are highly challenging but attainable. The key requirements are the stability of both the biologics and the powder, along with the powder dispersibility. The formulation to be developed depends on the manufacture process as it will subject the biologics to different stresses (temperature, mechanical and chemical) which could lead to degradation by different pathways. Stabilizing excipients coupled with the suitable choice of process can alleviate the stability issues of inhaled powders of biologics.

Inhalable Protein Powder Prepared by Spray-Freeze-Drying Using Hydroxypropyl-β-Cyclodextrin as Excipient

The prospect of inhaled biologics has garnered particular interest given the benefits of the pulmonary route of administration. Pertinent considerations in producing inhalable dry powders containing biological medicines relate to aerosol performance and protein stability. Spray-freeze-drying (SFD) has emerged as an established method to generate microparticles that can potentially be deposited in the lungs. Here, the SFD conditions and formulation composition were evaluated using bovine serum albumin (BSA) as a model protein and 2-hydroxypropyl-beta-cyclodextrin (HPβCD) as the protein stabilizer. A factorial design analysis was performed to investigate the effects of BSA content, solute concentration of feed solution, and atomization gas flow rate on dispersibility (as an emitted fraction), respirability (as fine particle fraction), particle size, and level of protein aggregation. The atomization gas flow rate was identified as a significant factor in influencing the aerosol performance of the powder formulations and protein aggregation. Nonetheless, high atomization gas flow rate induced aggregation, highlighting the need to further optimize the formulation. Of note, all the formulations exhibited excellent dispersibility, while no fragmentation of BSA occurred, indicating the feasibility of SFD and the promise of HPβCD as an excipient.

Dry Powder for Pulmonary Delivery: A Comprehensive Review

The pulmonary route has long been used for drug administration for both local and systemic treatment. It possesses several advantages, which can be categorized into physiological, i.e., large surface area, thin epithelial membrane, highly vascularized, limited enzymatic activity, and patient convenience, i.e., non-invasive, self-administration over oral and systemic routes of drug administration. However, the formulation of dry powder for pulmonary delivery is often challenging due to restrictions on aerodynamic size and the lung’s lower tolerance capacity in comparison with an oral route of drug administration. Various physicochemical properties of dry powder play a major role in the aerosolization, deposition, and clearance along the respiratory tract. To prepare suitable particles with optimal physicochemical properties for inhalation, various manufacturing methods have been established. The most frequently used industrial methods are milling and spray-drying, while several other alternative methods such as spray-freeze-drying, supercritical fluid, non-wetting templates, inkjet-printing, thin-film freezing, and hot-melt extrusion methods are also utilized. The aim of this review is to provide an overview of the respiratory tract structure, particle deposition patterns, and possible drug-clearance mechanisms from the lungs. This review also includes the physicochemical properties of dry powder, various techniques used for the preparation of dry powders, and factors affecting the clinical efficacy, as well as various challenges that need to be addressed in the future.

The Freeze-Drying of Foods-The Characteristic of the Process Course and the Effect of Its Parameters on the Physical Properties of Food Materials

Freeze-drying, also known as lyophilization, is a process in which water in the form of ice under low pressure is removed from a material by sublimation. This process has found many applications for the production of high quality food and pharmaceuticals. The main steps of the freeze-drying process, such as the freezing of the product and primary and secondary drying, are described in this paper. The problems and mechanisms of each step of the freeze-drying process are also analyzed. The methods necessary for the selection of the primary and secondary end processes are characterized. The review contains a description of the effects of process conditions and the selected physical properties of freeze-dried materials, such as structural properties (shrinkage and density porosity), color, and texture. The study shows that little attention is given to the mechanical properties and texture of freeze-dried materials obtained from different conditions of the lyophilization process.

Spray Freeze-Drying as a Solution to Continuous Manufacturing of Pharmaceutical Products in Bulk

Pharmaceutical manufacturing is evolving from traditional batch processes to continuous ones. The new global competition focused on throughput and quality of drug products is certainly the driving force behind this transition which, thus, represents the new challenge of pharmaceutical manufacturing and hence of lyophilization as a downstream operation. In this direction, the present review deals with the most recent technologies, based on spray freeze-drying, that can achieve this objective. It provides a comprehensive overview of the physics behind this process and of the most recent equipment design.

Physical stability of dry powder inhaler formulations

Introduction: Dry powder inhalers (DPIs) are popular for pulmonary drug delivery. Various techniques have been employed to produce inhalation drug particles and improve the delivery efficiency of DPI formulations. Physical stability of these DPI formulations is critical to ensure the delivery of a reproducible dose to the airways over the shelf-life.Areas covered: This review focuses on the impact of solid-state stability on aerosolization performance of DPI drug particles manufactured by powder production approaches and particle-engineering techniques. It also highlights the different analytical tools that can be used to characterize the physical instability originating from production and storage.Expert opinion: A majority of the DPI literature focuses on the effects of physico-chemical properties such as size, morphology, and density on aerosolization. While little has been reported on the physical stability, particularly the stability of engineered drug particles for use in DPIs. Literature data have shown that different particle-engineering methods and storage conditions may cause physical instability of dry powders for inhalation and can significantly change the aerosol performance. A systematic examination of physical instability mechanisms in DPI formulations is necessary during formulation development in order to select the optimum formulation with satisfactory stability. In addition, the use of appropriate characterization tools is critical to detect and understand physical instability during the development of DPI formulations.

Influence of stabilizer type and concentration on the lung deposition and retention of resveratrol nanosuspension-in-microparticles

The purpose of this study was to explore the influence of stabilizer type and concentration on the properties of spray dried nanosuspension-in-microparticles (NS-in-MPs) for inhalation. Taking resveratrol (RES) as a Biopharmaceutical Classification System II (BCS II) model drug, the RES containing nanosuspensions were fabricated by high pressure homogenization method with different stabilizers including sodium dodecyl sulphate (SDS), sodium alginate (SA), chitosan (CS) and polyvinyl alcohol (PVA). Then, the nanosuspensions were spray dried with mannitol to obtain inhalable NS-in-MPs. The particle size, morphology, drug existing state, in vitro aerodynamic performance, in vitro release behavior, lung retention and pharmacokinetic behaviors were characterized. It was found that the morphology, lung deposition as well as in vitro drug release from the microparticles were significantly influenced by stabilizer type, with 1% PVA as stabilizer presenting the highest fine particle fraction (FPF). Meanwhile, taking PVA as an example, it was found stabilizer concentration could alter morphology and flowability of the microparticles, and the FPF value decreased with the increase of stabilizer concentration. Further drug retention and in vivo pharmacokinetic studies demonstrated that the positively charged stabilizer CS could facilitate drug retention and minimize drug expose to the systemic circulation. In conclusion, the deposition and lung retention behavior of NS-in-MPs could be well tuned by selecting different type or concentration of stabilizers, which could facilitate local lung diseases therapy.

Effect of thermal and shear stresses in the spray drying process on the stability of siRNA dry powders

Pulmonary delivery of small interfering RNAs (siRNAs) has shown promising results for the treatment of lung diseases with gene disorders. The aim of this work was to evaluate the effect of processing-induced thermal and shear stresses during the spray drying process on the solid-state properties, the chemical integrity and the bioactivity of spray-dried siRNA powder intended for inhalation. To this end, inhalable siRNA dry powders composed of EGFP-siRNA and mannitol were prepared by using a lab-scale spray drier. Scanning electron microscopy (SEM), laser diffraction, and X-ray powder diffraction (XRPD) were used to characterize the solid-state properties of the spray-dried siRNA-mannitol powders. High performance liquid chromatography (HPLC) and flow cytometry were exploited to assess the chemical stability and cellular transfection efficiency of siRNA formulations, respectively. The results showed that the spray-dried particles changed from spherical to irregular shape with an increase in the inlet temperature. The high inlet temperature and intensive atomization conditions resulted in more agglomerates in the spray-dried particles. XRPD analysis indicated that the presence of siRNA affected the polymorphic form of mannitol in the spray-dried powder. Compromised chemical stability and cell transfection efficiency of siRNA were observed with an increase in the thermal stress and shear stress during the spray drying process. The chemical stability of siRNA in liquid state was more prone to thermal stress when compared to the stability in the solid-state. In conclusion, stable siRNA based particles for inhalation purposes could be produced using the spray drying technology.

Spray-Dried Particles of Nitric Oxide-Modified Glutathione for the Treatment of Chronic Lung Infection

Antibiotic resistance in pathogenic bacteria has emerged as a big challenge to human and animal health and significant economy loss worldwide. Development of novel strategies to tackle antibiotic resistance is of the utmost priority. In this study, we combined glutathione (GSH), a master antioxidant in all mammalian cells, and nitric oxide, a proven biofilm-dispersing agent, to produce GSNO. The resazurin biofilm viability assay, crystal violet biofilm assay, and confocal microscopy techniques showed that GSNO disrupted biofilms of both P. aeruginosa PAO1 and multidrug resistant A. baumaunii (MRAB 015069) more efficiently than GSH alone. In addition, GSNO showed a higher reduction in biofilm viability and biomass when combined with antibiotics. This combination treatment also inhibited A. baumaunii (MRAB 015069) growth and facilitated human foreskin fibroblast (HFF-1) confluence and growth simultaneously. A potentially inhalable GSNO powder with reasonable aerosol performance and antibiofilm activity was produced by spray drying. This combination shows promise as a novel formulation for treating pulmonary bacterial infections.

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.

Drying technology strategies for colon-targeted oral delivery of biopharmaceuticals

In chronic intestinal diseases like inflammatory bowel disease, parenteral administration of biopharmaceuticals is associated with numerous disadvantages including immune reactions, infections, low patient compliance, and toxicity caused by high systemic bioavailability. One alternative that can potentially overcome these limitations is oral administration of biopharmaceuticals, where the local delivery will reduce the systemic exposure and furthermore the manufacturing costs will be lower. However, the development of oral dosage forms that deliver the biologically active form to the intestines is one of the greatest challenges for pharmaceutical technologists due to the sensitive nature of biopharmaceuticals. The present article discusses the various drug delivery technologies used to produce orally administered solid dosage forms of biopharmaceuticals with an emphasis on colon-targeted delivery. Solid oral dosage compositions containing different types of colon-targeting biopharmaceuticals are compiled followed by a review of currently applied and emerging drying technologies for biopharmaceuticals. The different drying technologies are compared in terms of their advantages, limitations, costs and their effect on product stability.

Using two-fluid nozzle for spray freeze drying to produce porous powder formulation of naked siRNA for inhalation

Spray freeze drying is an attractive technology to produce powder formulation for inhalation. It can be used to generate large porous particles which tend to aerosolize efficiently and do not aggregate readily. It also avoids material to be exposed to elevated temperature. In this study, we reported the use of two-fluid nozzle to produce spray freeze dried powder of small interfering RNA (siRNA). The effect of atomization gas flow rate and liquid feed rate were inspected initially using herring sperm DNA (hsDNA) as nucleic acid model. The atomization gas flow rate was found to have a major impact on the aerosol properties. The higher the atomization gas flow rate, the smaller the particle size, the higher the fine particle fraction (FPF). In contrast, the liquid feed rate had very minor effect. Subsequently, spray freeze dried siRNA powder was produced at various atomization gas flow rates. The particles produced were highly porous as examined with the scanning electron microscopy, and the structural integrity of the siRNA was demonstrated with gel electrophoresis. The gene-silencing effect of the siRNA was also successfully preserved in vitro. The best performing siRNA formulation was prepared at the highest atomization gas flow rate investigated with a moderate FPF of 30%. However, this was significantly lower than that obtained with the corresponding hsDNA counterparts (FPF ∼57%). A direct comparison between the hsDNA and siRNA formulations revealed that the former exhibited a lower density, hence a smaller aerodynamic diameter despite similar geometric size.