Thin-film freeze-drying of an influenza virus hemagglutinin mRNA vaccine in unilamellar lipid nanoparticles with blebs.

Messenger RNA (mRNA) vaccines have revolutionized the fight against infectious diseases and are poised to transform other therapeutic areas. Lipid nanoparticles (LNP) represent the most successful delivery system for mRNA. While the mRNA-LNP products currently in clinics are stored as frozen suspensions, there is evidence that freeze-drying mRNA-LNP into dry powders can potentially enable their storage and handling at non-freezing temperatures. Previously, we successfully applied thin-film freeze-drying (TFFD) to transform a polyadenylic acid [poly(A)]-LNP formulation from a liquid suspension to dry powders. The poly(A)-LNP were structurally multilamellar spheres without blebs, but the mRNA vaccines in clinics are comprised of mRNA-LNP that are structurally spheres surrounded by a unilamellar lipid bilayer, with some containing blebs, and it was reported that the presence of blebs increases the sensitivity of mRNA-LNP to freeze-drying-induced stress. In the present study, using an influenza A virus hemagglutinin (HA) mRNA in LNP that were structurally similar to that in the COVID-19 mRNA vaccines currently in clinic, we studied the effect of TFFD on the physical properties, internal structure, as well as immunogenicity of the HA mRNA-LNP vaccine. We concluded that TFFD can be utilized to prepare dry powders of the HA mRNA-LNP, but a sufficient amount of excipients were needed to minimize changes in the physical properties, structure, and immunogenicity of the HA mRNA-LNP vaccine.

Inhalable dry powders of a monoclonal antibody against SARS-CoV-2 virus made by thin-film freeze-drying.

Monoclonal antibodies (mAbs) represent a promising modality for the prevention and treatment of viral infections. For infections that initiate from the respiratory tract, direct administration of specific neutralizing mAbs into lungs has advantages over systemic injection of the same mAbs. Herein, using AUG-3387, a human-derived mAb with high affinity to the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and its various variants, as a model mAb, we formulated the mAb into dry powders by thin-film freeze-drying, confirmed that the AUG-3387 mAb reconstituted from the dry powders retained their integrity, high affinity to the SARS-CoV-2 spike protein receptor binding domain (RBD), as well as ability to neutralize RBD-expressing pseudoviruses. Finally, we showed that one of the AUG-3387 mAb dry powders had desirable aerosol properties for pulmonary delivery into the lung. We concluded that thin-film freeze-drying represents a viable method to prepare inhalable powders of virus-neutralizing mAbs for pulmonary delivery into the lung.

Inhaled JAK Inhibitor GDC-0214 Nanoaggregate Powder Exhibits Improved Pharmacokinetic Profile in Rats Compared to the Micronized Form: Benefits of Thin Film Freezing.

Asthma is a common chronic disease affecting the airways in the lungs. The receptors of allergic cytokines, including interleukin (IL)-4, IL-5, and IL-13, trigger the Janus kinase (JAK)/signal transducer and activator of transcription (STAT) pathway, which involves the pathogenesis of asthma. GDC-0214 is a JAK inhibitor that was developed as a potent and selective target for the treatment of asthma, specifically targeting the lungs. While inhaled GDC-0214 is a promising novel treatment option against asthma, improvement is still needed to achieve increased potency of the powder formulation and a reduced number of capsules containing powder to be inhaled. In this study, high-potency amorphous powder formulations containing GDC-0214 nanoaggregates for dry powder inhalation were developed using particle engineering technology, thin film freezing (TFF). A high dose per capsule was successfully achieved by enhancing the solubility of GDC-0214 and powder conditioning. Lactose and/or leucine as excipients exhibited optimum stability and aerosolization of GDC-0214 nanoaggregates, and aerosolization of the dose was independent of air flow through the device between 2 and 6 kPa pressure drops. In the rat PK study, formulation F20, which contains 80% GDC-0214 and 20% lactose, resulted in the highest AUC0-24h in the lungs with the lowest AUC0-24h in the plasma that corresponds to a 4.8-fold higher ratio of the lung-to-plasma exposures compared to micronized crystalline GDC-0214 powder administered by dry powder inhalation. Therefore, GDC-0214 nanoaggregates produced by TFF provided an improved dry powder for inhalation that can lead to enhanced therapeutic efficacy with a lower risk of systemic toxicity.

Effect of lipid composition on RNA-Lipid nanoparticle properties and their sensitivity to thin-film freezing and drying.

A library of 16 lipid nanoparticle (LNP) formulations with orthogonally varying lipid molar ratios was designed and synthesized, using polyadenylic acid [poly(A)] as a model for mRNA, to explore the effect of lipid composition in LNPs on (i) the initial size of the resultant LNPs and encapsulation efficiency of RNA and (ii) the sensitivity of the LNPs to various conditions including cold storage, freezing (slow vs. rapid) and thawing, and drying. Least Absolute Shrinkage and Selection Operator (LASSO) regression was employed to identify the optimal lipid molar ratios and interactions that favorably affect the physical properties of the LNPs and enhance their stability in various stress conditions. LNPs exhibited distinct responses under each stress condition, highlighting the effect of lipid molar ratios and lipid interactions on the LNP physical properties and stability. It was then demonstrated that it is feasible to use thin-film freeze-drying to convert poly(A)-LNPs from liquid dispersions to dry powders while maintaining the integrity of the LNPs. Importantly, the residual moisture content in LNP dry powders significantly affected the LNP integrity.Residual moisture content of ≤ 0.5% or > 3-3.5% w/w negatively affected the LNP size and/or RNA encapsulation efficiency, depending on the LNP composition. Finally, it was shown that the thin-film freeze-dried LNP powders have desirable aerosol properties for potential pulmonary delivery. It was concluded that Design of Experiments can be applied to identify mRNA-LNP formulations with the desired physical properties and stability profiles. Additionally, optimizing the residual moisture content in mRNA-LNP dry powders during (thin-film) freeze-drying is crucial to maintain the physical properties of the LNPs.

Aerosolizable Plasmid DNA Dry Powders Engineered by Thin-film Freezing.

PURPOSE: This study was designed to test the feasibility of using thin-film freezing (TFF) to prepare aerosolizable dry powders of plasmid DNA (pDNA) for pulmonary delivery. METHODS: Dry powders of pDNA formulated with mannitol/leucine (70/30, w/w) with various drug loadings, solid contents, and solvents were prepared using TFF, their aerosol properties (i.e., mass median aerodynamic diameter (MMAD) and fine particle fraction (FPF)) were determined, and selected powders were used for further characterization. RESULTS: Of the nine dry powders prepared, their MMAD values were about 1-2 µm, with FPF values (delivered) of 40-80%. The aerosol properties of the powders were inversely correlated with the pDNA loading and the solid content in the pDNA solution before TFF. Powders prepared with Tris-EDTA buffer or cosolvents (i.e., 1,4-dioxane or tert-butanol in water), instead of water, showed slightly reduced aerosol properties. Ultimately, powders prepared with pDNA loading at 5% (w/w), 0.25% of solid content, with or without Tris-EDTA were selected for further characterization due to their overall good aerosol performance. The pDNA powders exhibited a porous matrix structure, with a moisture content of < 2% (w/w). Agarose gel electrophoresis confirmed the chemical integrity of the pDNA after it was subjected to TFF and after the TFF powder was actuated. A cell transfection study confirmed that the activity of the pDNA did not change after it was subjected to TFF. CONCLUSION: It is feasible to use TFF to produce aerosolizable pDNA dry powder for pulmonary delivery, while preserving the integrity and activity of the pDNA.

Entrapment of air microbubbles by ice crystals during freezing exacerbates freeze-induced denaturation of proteins.

Freezing techniques are an essential part of biologics manufacturing processes, yet the formation of ice/water interfaces can impart detrimental effects on proteins. However, the absence of chemical and structural differences between ice and liquid water poses the question as to why ice can destabilize proteins. We hypothesize that the destabilizing stress of the ice-liquid water interface does not originate from the ice-water system itself but rather from the air microbubbles present during the freezing process. As the temperature decreases, the dissolved air is expelled from the ice crystal lattices in the form of microbubbles and is subsequently trapped by the advancing ice front. This newly formed air-water interface represents an additional interfacial area for the proteins to be adsorbed onto and denatured. The result showed that freezing at âˆ¼ 1 K/s led to the formation of small circular microbubbles with diameters ranging from 100 µm to 500 µm. In contrast, slower freezing resulted in the formation of larger, elongated millimeter-size bubbles. The reduction of the number of microbubbles was carried out by the deaeration process using agitation under reduced pressure at 20 kPa. The resulting deaerated (i.e., low dissolved air) protein samples were frozen and monitored for the formation of subvisible aggregates using micro-flow imaging (MFI). The results demonstrated that deaerating the samples prior to intermediate freezing (i.e., TFF) reduced the number of aggregates for both highly surface-active and low surface-active proteins (lactoferrin and bovine IgG, respectively). This reduction was more pronounced in spray freeze drying (SFD) than thin-film freezing (TFF), and less apparent in conventional lyophilization.

The applications of Machine learning (ML) in designing dry powder for inhalation by using thin-film-freezing technology.

Dry powder inhalers (DPIs) are one of the most widely used devices for treating respiratory diseases. Thin--film--freezing (TFF) is a particle engineering technology that has been demonstrated to prepare dry powder for inhalation with enhanced physicochemical properties. Aerosol performance, which is indicated by fine particle fraction (FPF) and mass median aerodynamic diameter (MMAD), is an important consideration during the product development process. However, the conventional approach for formulation development requires many trial-and-error experiments, which is both laborious and time consuming. As a state-of-the art technique, machine learning has gained more attention in pharmaceutical science and has been widely applied in different settings. In this study, we have successfully built a prediction model for aerosol performance by using both tabular data and scanning electron microscopy (SEM) images. TFF technology was used to prepare 134 dry powder formulations which were collected as a tabular dataset. After testing many machine learning models, we determined that the Random Forest (RF) model was best for FPF prediction with a mean absolute error of ± 7.251%, and artificial neural networks (ANNs) performed the best in estimating MMAD with a mean absolute error of ± 0.393 µm. In addition, a convolutional neural network was employed for SEM image classification and has demonstrated high accuracy (>83.86%) and adaptability in predicting 316 SEM images of three different drug formulations. In conclusion, the machine learning models using both tabular data and image classification were successfully established to evaluate the aerosol performance of dry powder for inhalation. These machine learning models facilitate the product development process of dry powder for inhalation manufactured by TFF technology and have the potential to significantly reduce the product development workload. The machine learning methodology can also be applied to other formulation design and development processes in the future.

Formulation of dry powders of vaccines containing MF59 or AddaVax by Thin-Film Freeze-Drying: Towards a dry powder universal flu vaccine.

MF59® is an oil-in-water (O/W) nanoemulsion-based vaccine adjuvant that is often used in seasonal and pandemic influenza vaccines. We explored the feasibility of developing dry powders of vaccines adjuvanted with MF59 or AddaVax™, a preclinical grade equivalent of MF59 with the same composition and droplet size as MF59, by thin-film freeze-drying (TFFD). Liquid AddaVax alone was successfully converted to a dry powder by TFFD using trehalose as a stabilizing agent while maintaining the droplet size distribution of AddaVax after it was reconstituted. TFFD was then applied to convert liquid AddaVax-adjuvanted vaccines containing either a model antigen (e.g., ovalbumin) or mono-, bi-, and tri-valent recombinant hemagglutinin (rHA) protein-based H1 and/or H3 (universal) influenza vaccine candidates, as well as the MF59-containing Fluad® Quadrivalent influenza vaccine to dry powders. Both antigens and stabilizing agents affected the physical properties of the vaccines (e.g., mean particle size and particle size distribution) after the vaccines were subjected to TFFD. Importantly, the integrity and hemagglutination activity of the rHA antigens did not significantly change and the immunogenicity of reconstituted influenza vaccine candidates was maintained when evaluated in a mouse model. The vaccine dry powder was not sensitive to repeated freezing-and-thawing, in contrast to its liquid counterpart. It is concluded that TFFD can be applied to convert liquid vaccines containing MF59 or AddaVax to dry powders while maintaining the immunogenicity of the vaccines. Ultimately, TFFD technology may be used to prepare dry powders of multivalent universal influenza vaccines.

Development of (Inhalable) Dry Powder Formulations of AS01B-Containing Vaccines Using Thin-Film Freeze-Drying.

AS01B is a liposomal formulation of two immunostimulants namely 3-O-desacyl-4́-monophosphoryl lipid A (MPL) and QS-21. The liposomal formulation of AS01B reduces the endotoxicity of MPL and the lytic activity of QS-21. The AS01B-adjuvanted Shingrix vaccine is marketed in a two-vial presentation, with the liquid AS01B liposomes in one vial and the antigen as a dry powder in another vial. In the present study, we tested the feasibility of applying thin-film freeze-drying (TFFD) to engineer dry powders of the AS01B liposomal adjuvant alone or vaccines containing AS01B as an adjuvant. Initially, we showed that after the AS01B liposomal adjuvant was subjected to TFFD using sucrose as a stabilizer at 4% w/v, the particle size distribution of AS01B liposomes reconstituted from the dry powder was identical to the liquid adjuvant before drying. We then showed using ovalbumin (OVA) as a model antigen adjuvanted with AS01B (AS01B/OVA) that subjecting the AS01B/OVA vaccine to TFFD and subsequent reconstitution did not negatively affect the AS01B liposome particle size, nor the immunogenicity of the vaccine. Importantly, the thin-film freeze-dried AS01B/OVA vaccine, unlike its liquid counterpart, was not sensitive to repeated freezing-and-thawing. The developed AS01B/OVA dry powder also showed the desirable aerosol properties (i.e., fine particle fraction of 66.3 ± 4.9% and mass median aerodynamic diameter of 2.4 ± 0.1 µm) for potential pulmonary administration. Finally, the feasibility of using TFFD to prepare dry powders of AS01B-adjuvanted vaccines was further confirmed using AS01B-adjuvanted Fluzone Quadrivalent and Shingrix, which contains AS01B. It is concluded that the TFFD technology can enable the formulation of AS01B-adjuvanted vaccines as freezing-insensitive, inhalable dry powders in a single-vial presentation.

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 ß-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 ß-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 ß-galactosidase, was determined to range from 2 to 10% depending on the air-flow rate of the spraying process.

Dry powders for inhalation containing monoclonal antibodies made by thin-film freeze-drying.

Thin-film freeze-drying (TFFD) is a rapid freezing and then drying technique used to prepare inhalable dry powders from the liquid form for applications such as drug delivery to the lungs. Herein we report the preparation of aerosolizable dry powders of monoclonal antibodies (mAbs) by TFFD. We first formulated an IgG antibody with lactose/leucine (60:40, w/w) or trehalose/leucine (75:25) and tested their aerosol performance. The IgG 1% (w/w) formulated with lactose/leucine (60:40, w/w) in phosphate buffered saline (PBS) (IgG-1-LL-PBS) and processed by TFFD was found to produce the powder with desirable aerosol properties. We then replaced the IgG with anti-programmed cell death protein (anti-PD-1 mAb), a specific antibody, to prepare a dry powder (anti-PD1-1-LL-PBS), which performed similarly to the IgG-1-LL-PBS powder. The aerosol properties of the anti-PD1-1-LL-PBS dry powder were significantly better when TFFD was used to prepare the powder than when conventional shelf freeze-drying (shelf FD) was used. The TFFD dry powder had a porous structure with nanoaggregates and had a Tg value between 39 and 50 °C. When stored at room temperature, the anti-PD-1 mAb in the TFFD powder was more stable than that of the same formulation stored as a liquid. The addition of polyvinylpyrrolidone K40 in the formulation raised the Tg to 152 °C, which is expected to further increase the storage stability of the mAbs. The PD-1 binding activity of the anti-PD-1 mAbs after TFFD was not different from before TFFD. While protein loss, likely due to protein binding to vials and the thin-film freezing apparatus, was identified, we were able to minimize the loss by increasing the mAb concentration (i.e., from 1% to 13.2%). Micro-flow imaging revealed that the excipients and PBS affected subvisible aggregate formation. More subvisible mAb aggregates were generated when PBS was used, but the mAb content in the dry powders did not significantly affect the total subvisible aggregate count. Powders prepared with mannitol as an excipient showed the least amount of subvisible mAb aggregates. Finally, we showed that anti-TNF-α, another mAb, can also be converted to a dry powder with a similar composition by TFFD. We conclude that TFFD can be applied to produce stable, aerosolizable dry powders of mAbs for pulmonary delivery and that formulations must be optimized to maximize aerosol performance and minimize protein aggregation.

Increasing Drug Loading of Weakly Acidic Telmisartan in Amorphous Solid Dispersions through pH Modification during Hot-Melt Extrusion.

Oral drug therapy requiring large quantities of active pharmaceutical ingredients (APIs) can cause a substantial pill burden, which can increase nonadherence and worsen healthcare outcomes. Maximizing the drug loading of APIs in oral dosage forms is essential to reduce pill burden. This can be challenging for poorly water-soluble APIs without compromising performance. We show a promising strategy for maximizing the drug loading of pH-dependent APIs in amorphous solid dispersions (ASDs) produced by hot-melt extrusion (HME) without compromising their dissolution performance. We examine potential increases in the drug loading (w/w) of telmisartan in ASDs by incorporating bases to modify pH during HME. Telmisartan is a weakly acidic, poorly water-soluble API with pH-dependent solubility. It is practically insoluble at physiological pH, but its solubility increases exponentially at pH values above 10. Telmisartan was extruded with the polymer Soluplus and various bases. With no base, the maximum drug loading achieved by extrusion was only 5% before crystalline telmisartan was detected. Including a strong, water-soluble base (NaOH or KOH) increased the maximum amorphous drug loading to 50%. These results indicate that telmisartan has pH-dependent solubility in a molten polymer, similar to that in an aqueous solution. We also examine the stability of Soluplus when extruded with a strong base, using solid-state nuclear magnetic resonance (ssNMR) to determine that NaOH (but not KOH) causes degradation by hydrolysis. Supersaturation was maintained for at least 20 h during dissolution testing of a 50% telmisartan ASD in biorelevant media.

Niclosamide inhalation powder made by thin-film freezing: Multi-dose tolerability and exposure in rats and pharmacokinetics in hamsters.

In this work, we have developed and tested a dry powder form of niclosamide made by thin-film freezing (TFF) and administered it by inhalation to rats and hamsters to gather data about its toxicology and pharmacokinetics. Niclosamide, a poorly water-soluble drug, is an interesting drug candidate because it was approved over 60 years ago for use as an anthelmintic medication, but recent studies demonstrated its potential as a broad-spectrum antiviral with pharmacological effect against SARS-CoV-2 infection. TFF was used to develop a niclosamide inhalation powder composition that exhibited acceptable aerosol performance with a fine particle fraction (FPF) of 86.0% and a mass median aerodynamic diameter (MMAD) and geometric standard deviation (GSD) of 1.11 µm and 2.84, respectively. This formulation not only proved to be safe after an acute three-day, multi-dose tolerability and exposure study in rats as evidenced by histopathology analysis, and also was able to achieve lung concentrations above the required IC90 levels for at least 24 h after a single administration in a Syrian hamster model. To conclude, we successfully developed a niclosamide dry powder inhalation that overcomes niclosamide's limitation of poor oral bioavailability by targeting the drug directly to the primary site of infection, the lungs.

In vivo pharmacokinetic study of remdesivir dry powder for inhalation in hamsters.

Remdesivir dry powder for inhalation was previously developed using thin film freezing (TFF). A single-dose 24-h pharmacokinetic study in hamsters demonstrated that pulmonary delivery of TFF remdesivir can achieve plasma remdesivir and GS-441524 levels higher than the reported EC50s of both remdesivir and GS-441524 (in human epithelial cells) over 20 h. The half-life of GS-4412524 following dry powder insufflation was about 7 h, suggesting the dosing regimen would be twice-daily administration. Although the remdesivir-Captisol® (80/20 w/w) formulation showed faster and greater absorption of remdesivir and GS-4412524 in the lung, remdesivir-leucine (80/20 w/w) exhibited a greater Cmax with shorter Tmax and lower AUC of GS-441524, indicating lower total drug exposure is required to achieve a high effective concentration against SAR-CoV-2. In conclusion, remdesivir dry powder for inhalation would be a promising alternative dosage form for the treatment of COVID-19 disease.

Thin-Film Freeze-Drying Is a Viable Method to Convert Vaccines Containing Aluminum Salts from Liquid to Dry Powder.

Aluminum salts are used as an adjuvant in many human and veterinary vaccines. However, aluminum salt-adjuvanted vaccines are sensitive to temperature change and must be stored at 2-8 °C. Inadvertently exposing them to slow freezing temperatures can cause irreversible aggregation of aluminum salt microparticles and loss of potency and/or immunogenicity of the vaccines. There have been efforts to overcome this limitation by either adding stabilizing agents to the liquid vaccine or converting the vaccine from a liquid to a dry powder. Thin-film freeze-drying (TFFD) has proven to be an effective process to convert aluminum salt-adjuvanted vaccines from liquid to dry powder without causing particle aggregation or loss of immunogenicity upon reconstitution. This chapter provides a review of the TFFD process and examples for preparing stable aluminum salt-adjuvanted vaccine dry powders using TFFD.

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.

Using thin film freezing to minimize excipients in inhalable tacrolimus dry powder formulations.

We investigated the feasibility of preparing high-potency tacrolimus dry powder for inhalation using thin film freezing (TFF). We found that using ultra-rapid freezing can increase drug loading up to 95% while maintaining good aerosol performance. Drug loading affected the specific surface area and moisture sorption of TFF formulations, but it did not affect the chemical stability, physical stability, and dissolution of tacrolimus. Tacrolimus remained amorphous after storage at 40 °C/75% RH, and 25 °C/60% RH for up to 6 months. Lactose functioned as a bulking agent, and it had little to no effect as a stabilizer for amorphous tacrolimus due to a lack of interaction between the drug and excipient. Additionally, the aerosol performance of TFF tacrolimus/lactose (95/5) did not significantly change after six months of storage at 25 °C/60% RH. For processing parameters, the solids content and the processing temperature did not affect the aerosol performance of tacrolimus. Furthermore, both low- and high-resistance RS01 showed optimal and consistent aerosol performance over the 1-4 kPa pressure drop range. In conclusion, TFF is a suitable technology for producing inhalable powder that contain high drug loading and have less flow rate dependence.

Formulation Composition and Process Affect Counterion for CSP7 Peptide.

Counterions commonly remain with peptides in salt form after peptide purification. In animal and human studies, acetate counterions are a safer and more acceptable choice for peptides than others (e.g., trifluoroacetate counterions). Various salt forms of caveolin-1 scaffolding domain (CSP7) affect counterion volatilization. The development of lyophilized formulations containing volatile compounds is a challenge because these compounds sublimate away during the process. This work aims to investigate the effect of excipients and lyophilization parameters on the preservation of volatile compounds after lyophilization. The peak areas obtained from 1H and 19F NMR spectra were used to calculate the molar ratio of counterions to CSP7. We found that the pH modifier excipient had the greatest impact on the loss of counterions. By optimizing the molar ratio of bulking agent to CSP7, volatile compounds can be preserved after lyophilization. Higher chamber pressure during lyophilization can lower the sublimation rate of volatile compounds. Moreover, the loss of volatile compounds affects the stability of CSP7 due to the pH shift of reconstituted solutions, thereby causing peptide aggregation. The optimization of the formulation and processing helps preserve volatile compounds, thus minimizing the pH change of reconstituted solutions and maintaining the stability of peptide.