Next Generation Impactor Research Articles

Spray Dried Polymyxin B Liposome for Inhalation Against Gram-Negative Bacteria

This study aimed to provide an alternative and effective delivery system to combat polymyxin B (PMB) toxicity and bacterial resistance through inhalation therapy. PMB was formulated as liposomal dry powder for inhalation using thin-film hydration and spray-dried methods. PMB formulations were characterized physically. The aerodynamic properties were determined using next-generation impactor (NGI). In vitro drug release was done in a phosphate buffer pH 7.4 for 2 h. Cytotoxicity was evaluated by the MTT cell viability assay. Antimicrobiological activities were done using bioassay and flow cytometry. Particle sizes of the spay-dried formulations were between 259.83 ± 9.91 and 518.73 ± 27.08 nm while the zeta potentials ranged between 3.07 ± 0.27 mV and 4.323 ± 0.36 mV. The FT-IR shows no interaction between PMB and other excipients. DSC thermograms revealed amorphousness of the formulated powders and SEM revealed spherical PMB formulations. Similarly, MMAD results were 1.72–2.75 nm, and FPF was 25–26%. The cumulative release of the PMB formulations was 90.3 ± 0.6% within 2 h. The killing kinetics revealed total cell death at 12 and 24 h for Pseudomonas aeruginosa and Escherichia coli respectively. The PMB inhalation liposome showed better activity and was safe for lung-associated cell lines.

Design and development of DSPE-PEG2000/DPPC disk-like micelles for targeted delivery of icariin phytochemical in pulmonary fibrosis

Icariin (ICA)-loaded DSPE-PEG2000/DPPC disk-like micelles were synthesized utilizing the thin film hydration method to enhance the solubility and delivery of ICA to the lungs. The micellar formulation significantly improved the water solubility of ICA. This was attributed to the high encapsulation efficiency (95 %) and drug loading capacity (12 %) of the DSPE-PEG2000/DPPC micelles. Comprehensive characterization using Fourier-transform infrared spectroscopy (FT-IR) and X-ray diffraction (XRD). Particle size analysis through dynamic light scattering (DLS) and transmission electron microscopy (TEM) demonstrated the formation of stable micelles with an average particle size around 10 nm.In vitro aerosolization studies using the next-generation impactor (NGI) revealed that the fine particle fraction was 63.5 ± 4 %, which means that over 60 % of the aerosolized ICA/DSPE-PEG2000/DPPC micelles were capable of reaching and targeting the deep lung alveoli, indicating their potential efficacy for pulmonary delivery. Cytotoxicity assessments via the MTT assay showed IC50 values of ICA-loaded DSPE-PEG2000/DPPC micelles were 117 ± 8 μg/mL, 29 ± 3 μg/mL, and 21 ± 1 μg/mL at 24, 48, and 72 h, respectively, highlighting the time-dependent cytotoxic effects of the ICA-loaded micelles on A549 cells. However, the IC50 values of free ICA were > 500 μg/mL, 252 ± 3 μg/mL, and 109 ± 2 μg/mL, respectively at three different time points. That indicated that ICA-loaded nano micelles enhanced the cytotoxicity of ICA. Furthermore, the cellular uptake of the nano micelles by A549 cells was visualized and confirmed using EVOS fluorescence imaging and flow cytometry techniques. In addition, RAW 264.7 M2 polarization studies indicated ICA loaded DSPE-PEG2000/DPPC micelles have potential for treating pulmonary fibrosis.These findings suggest that DSPE-PEG2000/DPPC micelles significantly enhance the solubility and delivery of ICA, presenting a promising nanocarrier system for targeted pulmonary fibrosis therapy.

Bioaerosol sampling and bioanalysis: Applicability of the next generation impactor for quantifying Legionella pneumophila in droplet aerosols by flow cytometry

Bioaerosol generation, sampling, and cultivation-independent quantification of pathogenic bacteria play a crucial role in studying dose-response effects of Legionella pneumophila. Here, the Next Generation Impactor (NGI), initially created for pharmaceutical inhaling studies, was assessed for its potential to sample airborne bioaerosols and to separate size-dependent wet droplets by incrementally increasing the airflow speed. This stainless-steel sampler was shown in this study to be suitable for sampling prior to cultivation-independent analysis of pathogen-containing bioaerosols using washable cups. The applicability was studied by quantifying the total and intact cell count of L. pneumophila by flow cytometry after being dispersed into a droplet aerosol. Our results demonstrate a high total sampling efficiency of 95.5% ± 11.8% despite a lower biological sampling efficiency of 59.7% ± 16.5% for dry aerosols. However, by elevating the relative humidity (RH) to 100% in a liquid aerosolization unit, the biological sampling efficiency increased to over 90% for L. pneumophila. More than 50% of the cells were found in stage 1 using the liquid aerosolization unit. In comparison, 80% of the cells were sampled in stages 4–6 at 30% RH. Specifically, while at 100% RH, the droplet size mattered, at 30% RH, the size distribution of dry particles, in this case L. pneumophila, was relevant due to evaporation processes, which explains the size differences. These findings indicate the potential of the NGI for further exploration and application in studying other aerosol-borne pathogens, especially concerning the size distribution of wet droplets, viability, or effect-based bioanalysis.

Spray drying of a zinc complexing agent for inhalation therapy of pulmonary fibrosis

Pulmonary fibrosis, a disabling lung disease, results from the fibrotic transformation of lung tissue. This fibrotic transformation leads to a deterioration of lung capacity, resulting in significant respiratory distress and a reduction in overall quality of life. Currently, the frontline treatment of pulmonary fibrosis remains limited, focusing primarily on symptom relief and slowing disease progression. Bacterial infections with Pseudomonas aeruginosa are contributing to a severe progression of idiopathic pulmonary fibrosis.Phytic acid, a natural chelator of zinc, which is essential for the activation of metalloproteinase enzymes involved in pulmonary fibrosis, shows potential inhibition of LasB, a virulence factor in P. aeruginosa, and mammalian metalloproteases (MMPs). In addition, phytic acid has anti-inflammatory properties believed to result from its ability to capture free radicals, inhibit certain inflammatory enzymes and proteins, and reduce the production of inflammatory cytokines, key signaling molecules that promote inflammation. To achieve higher local concentrations in the deep lung, phytic acid was spray dried into an inhalable powder. Challenges due to its hygroscopic and low melting (25 °C) nature were mitigated by converting it to sodium phytate to improve crystallinity and powder characteristics. The addition of leucine improved aerodynamic properties and reduced agglomeration, while mannitol served as carrier matrix. Size variation was achieved by modifying process parameters and were evaluated by tools such as the Next Generation Impactor (NGI), light diffraction methods, and scanning electron microscopy (SEM). An inhibition assay for human MMP-1 (collagenase-1) and MMP-2 (gelatinase A) allowed estimation of the biological effect on tissue remodeling enzymes. The activity was also assessed with respect to inhibition of bacterial LasB. The formulated phytic acid demonstrated an IC50 of 109.7 µg/mL for LasB with viabilities > 80 % up to 188 µg/mL on A549 cells. Therefore, inhalation therapy with phytic acid-based powder shows promise as a treatment for early-stage Pseudomonas-induced pulmonary fibrosis.

Development of SIMPATEC-USP: An abbreviated impactor for rapid testing of inhalation devices

Cascade impactors like the Andersen Cascade Impactor (ACI) and Next Generation Impactor (NGI) are complex and costly due to multiple stages. This study introduces SIMPATEC-USP (Simplified Impactor Developed at the University of São Paulo), a low-cost, single-stage alternative meeting US Pharmacopeia standards for testing dry powder inhalers (DPIs). SIMPATEC-USP simplifies particle retention into a single Petri dish stage, eliminating multi-stage complexity. Its design includes a straightforward closure system for easy assembly/disassembly. A collection chamber holds a glass Petri dish with filter paper for final filtration, ensuring efficient aerosol product collection. SIMPATEC-USP also offers potential use with culture media for applications like antibacterial screening. Operating at 30 L/min, SIMPATEC-USP consists of three parts: a single-stage chamber, an L-shaped tube mimicking the trachea, and a vacuum pump. Aerosol particles are deposited onto the Petri dish via a nozzle, and the collected sample is weighed to determine drug concentration. Tested with inhalation-grade lactose, SIMPATEC-USP effectively collects and analyzes particles, allowing for rapid aerodynamic comparison of formulations, capsule retention assessment, and sample collection for drug release studies. The results demonstrate that it is possible to evaluate the performance of three inhalation devices regarding the mass migrating to the collection plate and that retained within the device itself. In conclusion, SIMPATEC-USP is highly suitable for exploratory studies and educational activities in pharmaceutical technology and pulmonary drug delivery systems.

Mucus, airway and plume temperature effects on pMDI-drug delivery in a mouth-throat airway: Experimental and numerical studies

Effective pulmonary drug delivery through pressurized-metered dose inhalers (pMDIs) depends on accurately targeting pharmaceutical aerosols to specific lung areas. Achieving this necessitates a comprehensive understanding of airflow dynamics in the airway and particle transport mechanisms.In this study, a replica of the realistic geometry of the VCU medium-sized mouth-throat (MT) airway was fabricated by rapid prototyping (3D printing) to connect to a next-generation impactor (NGI) setup. The drug concentration deposited in the replica was measured at a constant flow rate of 30 L/min and room temperature using a high-performance liquid chromatography (HPLC) assay. This measurement validated our computational fluid dynamics (CFD) model for simulating particle transport under the same conditions. Large eddy simulation (LES) and discrete phase model (DPM) were employed to model the MT's airflow and particle transport. Using our CFD modeling, we focused on the effects of the temperature distribution of aerosol injection (plume), the influence of inlet air temperature, and the presence of the mucus layer on particle transport and deposition.Our findings revealed that decreasing the plume temperature from 10 °C to −54 °C reduced deposition by approximately 15%, although increasing the average deposited particle sizes within the MT by about 34.5%. The airflow pattern, affected by different plume temperatures, was the prevalent parameter in particle MT deposition. In contrast, the effect of different air inlet temperatures on deposition was negligible. Additionally, incorporating mucus layer features in CFD modelling could further modify the inhaler's efficiency by up to 11%, depending on the specific conditions like diverse plume temperature (−54 °C–10 °C) and airflow temperature conditions (−15 °C–45 °C).

Novel inhaled andrographolide for treatment of lung cancer: In vitro assessment

Andrographolide is a plant-based compound that showed promising activity against lung cancer. However, the compound's poor water solubility and low bioavailability limit its oral administration. Inhaled drug delivery of andrographolide is highly favourable as it delivers active ingredients directly into the affected lungs. In the current study, we compared in vitro aerosol performance, anti-cancer activity and storages stability of two (2) inhalable andrographolide formulations. Formulation 1 was prepared using precipitation and spray drying techniques, while Formulation 2 was prepared via direct spray drying technique. Drug morphology and physicochemical properties were confirmed using scanning electron microscopy (SEM) and X-ray diffraction (XRD) analysis. In vitro aerosol dispersion profile was evaluated using the next-generation impactor (NGI). Formulation 1 consisted of elongated crystals while Formulation 2 was made up of amorphous spherical particles. Both formulations had an inhalable fraction (<5 μm) of more than 40 %, making them suitable for pulmonary drug delivery. The formulations also showed an IC25 of less than 100 μg/mL against the human lung carcinoma cells (A549). Formulation 1 and 2 was stable in a vacuum condition at 30 °C for up to 6 and 3 months, respectively. Novel inhalable andrographolide dry powders were successfully produced with a good aerosol profile, potent anti-cancer activity and adequate storage stability, which deserve further in vivo investigations.

Aerosol deposition and emission from a United States Pharmacopeia‐induction port when using a pressurized metered‐dose inhaler with and without a valved holding chamber

AbstractThe testing of pharmaceutical aerosols includes measuring the aerodynamic particle size distribution, which is usually performed on cascade impactors. In the next generation impactor (NGI), the aerosol dose is introduced through an induction port (IP), being separated into different aerodynamic diameter ranges by seven stages and a micro‐orifice collector. The IP plays an important role in estimating the oropharyngeal deposition fraction. While the IP retains mainly large particles, it also tends to retain particles in the respirable range. In this work, the deposition of particles in the IP of an NGI is studied, both experimentally and through computational fluid dynamic (CFD) simulations. Experimental tests are conducted both with the pressurized metered‐dose inhaler (pMDI) alone and in conjunction with a cylindrical valved holding chamber (VHC). For each case, the total mass deposition that occurs in the VHC, IP, and NGI stages is measured, as well as the mass median aerodynamic diameter of the aerosol leaving the IP. The CFD simulations show minimal variations in results regardless of the injection method due to the relatively low velocity and spray angle of the pMDI‐generated aerosol. If the flap‐valve is removed from the VHC, significant particle deposition occurs upstream or within the valve region, with downstream air recirculation contributing to small particle deposition. Based on the CFD results, a correlation is proposed to accurately predict the particle escape fraction of the IP and VHC, which allows estimation of the tannin distribution of particles collected in the NGI stages, especially those corresponding to the range of respirable particles.

Compatibility study of formoterol fumarate-lactose dry powder inhalation formulations: Spray drying, physical mixture and commercial DPIs

Formoterol fumarate (FF) is a long-acting beta-adrenergic receptor agonist that is administered as a dry powder inhaler (DPI) for chronic respiratory conditions. In most DPI formulations, the drug substance and the carrier are the two major components. Lactose is the most common carrier, which can undergo a Maillard reaction in the presence of primary and secondary amines. FF contains a secondary amine. Since the potential for Maillard reaction in DPI formulations has not been investigated yet, this study aims to investigate any potential reaction between lactose and FF. The formulations were prepared using a tubular mixer and spray drying techniques. FF and lactose were blended using a tubular mixer (TM FF-Lac). In the spray drying method, FF and lactose were dissolved in distilled water: MeOH and then spray dried (SD FF-Lac). The samples were stored at both ambient conditions and elevated temperature and humidity (40 °C ± 2, 75% ± 5 RH), and subsequently analyzed to identify any signs of incompatibilities. Differential scanning calorimetry (DSC), field emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), thin-layer chromatography (TLC), high-performance liquid chromatography (HPLC), and liquid chromatography-mass spectrometry (LC-MS-MS) were employed for sample analysis. The in vitro aerosolization performance was evaluated using a next-generation impactor (NGI). The results showed that the colour of the DPI formulations changed from white to brown after storage at elevated temperature and humidity. Although the SD FF-Lac had better aerosolization properties, it was more vulnerable to degradation due to its amorphous nature. The FF-lactose adduct was formed in all samples. Interestingly, adduct compounds were also detectable before the storage for stability and stress tests. Incompatibility was confirmed by HPLC-PDA analysis. The mass spectra revealed the m/z of the adduct compound and confirmed the Millard reaction. Browning occurred in the prepared DPI formulations following storage at elevated temperature and humidity. Moreover, adduct compounds were also found in DPI formulations kept at ambient conditions and commercial DPI. Overall, mass spectroscopy was capable of detecting the incompatibility.

Synergistic combination of antimicrobial peptide and isoniazid as inhalable dry powder formulation against multi-drug resistant tuberculosis

Multidrug-resistant tuberculosis (MDR-TB) has posed a serious threat to global public health, and antimicrobial peptides (AMPs) have emerged to be promising candidates to tackle this deadly infectious disease. Previous study has suggested that two AMPs, namely D-LAK120-A and D-LAK120-HP13, can potentiate the effect of isoniazid (INH) against mycobacteria. In this study, the strategy of combining INH and D-LAK peptide as a dry powder formulation for inhalation was explored. The antibacterial effect of INH and D-LAK combination was first evaluated on three MDR clinical isolates of Mycobacteria tuberculosis (Mtb). The minimum inhibitory concentrations (MICs) and fractional inhibitory concentration indexes (FICIs) were determined. The combination was synergistic against Mtb with FICIs ranged from 0.25 to 0.38. The INH and D-LAK peptide at 2:1 mole ratio (equivalent to 1: 10 mass ratio) was identified to be optimal. This ratio was adopted for the preparation of dry powder formulation for pulmonary delivery, with mannitol used as bulking excipient. Spherical particles with mass median aerodynamic diameter (MMAD) of around 5 µm were produced by spray drying. The aerosol performance of the spray dried powder was moderate, as evaluated by the Next Generation Impactor (NGI), with emitted fraction and fine particle fraction of above 70 % and 45 %, respectively. The circular dichroism spectra revealed that both D-LAK peptides retained their secondary structure after spray drying, and the antibacterial effect of the combination against the MDR Mtb clinical isolates was successfully preserved. The combination was found to be effective against MDR Mtb isolates with KatG or InhA mutations. Overall, the synergistic combination of INH with D-LAK peptide formulated as inhaled dry powder offers a new therapeutic approach against MDR-TB.

Aspherical, Nano-Structured Drug Delivery System with Tunable Release and Clearance for Pulmonary Applications.

Addressing the challenge of efficient drug delivery to the lungs, a nano-structured, microparticulate carrier system with defined and customizable dimensions has been developed. Utilizing a template-assisted approach and capillary forces, particles were rapidly loaded and stabilized. The system employs a biocompatible alginate gel as a stabilizing matrix, facilitating the breakdown of the carrier in body fluids with the subsequent release of its nano-load, while also mitigating long-term accumulation in the lung. Different gel strengths and stabilizing steps were applied, allowing us to tune the release kinetics, as evaluated by a quantitative method based on a flow-imaging system. The micro-cylinders demonstrated superior aerodynamic properties in Next Generation Impactor (NGI) experiments, such as a smaller median aerodynamic diameter (MMAD), while yielding a higher fine particle fraction (FPF) than spherical particles similar in critical dimensions. They exhibited negligible toxicity to a differentiated macrophage cell line (dTHP-1) for up to 24 h of incubation. The kinetics of the cellular uptake by dTHP-1 cells was assessed via fluorescence microscopy, revealing an uptake-rate dependence on the aspect ratio (AR = l/d); cylinders with high AR were phagocytosed more slowly than shorter rods and comparable spherical particles. This indicates that this novel drug delivery system can modulate macrophage uptake and clearance by adjusting its geometric parameters while maintaining optimal aerodynamic properties and featuring a biodegradable stabilizing matrix.

Nanocrystal Agglomerates of Curcumin Prepared by Electrospray Drying as an Excipient-Free Dry Powder for Inhalation.

Curcumin has shown beneficial effects on pulmonary diseases with chronic inflammation or abnormal inflammatory responses, including chronic obstructive pulmonary disease, asthma, and pulmonary fibrosis. Clinical applications of curcumin are limited due to its chemical instability in solution, low water solubility, poor oral bioavailability, and intestinal and liver first-pass metabolism. Pulmonary delivery of curcumin can address these challenges and provide a high concentration in lung tissues. The purpose of the current work was to prepare a novel inhalable dry powder of curcumin nanocrystals without added excipients using electrospray drying (ED) with improved dissolution and aerosolization properties. ED of curcumin was performed at 2 and 4% w/v concentrations in acetone. Physicochemical properties of the formulated powders were evaluated by powder X-ray diffraction (PXRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), density and powder flow measurements, and in vitro dissolution. The in vitro deposition studies were conducted using next-generation impactor (NGI) and aerosol performance and aerodynamic particle size parameters were calculated for prepared formulations. ED could produce agglomerates of nanocrystals with a size of about 500 nm at an acceptable yield of about 50%. PXRD and FTIR data revealed that prepared nanocrystals were in a stable crystalline state. The bulk and tapped density of prepared agglomerates were in the range appropriate for pulmonary delivery. Formed nanocrystals could significantly improve the dissolution rate of water-insoluble curcumin. The optimized formulation exhibited acceptable recovered dose percentage, high emitted dose percentage, optimum mean mass median aerodynamic diameter, small geometric standard deviation, and high fine-particle fraction that favors delivery of curcumin to the deep lung regions. The ED proved to be an efficient technique to prepare curcumin nanocrystals for pulmonary delivery in a single step, at a mild condition, and with no surfactant.

An experimental study of the effect of individual upper airway anatomical features on the deposition of dry powder inhaler formulations

This study aims to investigate the effects of different pharynx anatomical features on the delivery of inhaled aerosols. Six in-vitro upper airway models reconstructed using anatomical images acquired by Magnetic Resonance Imaging (MRI) were used for the experiments. A geometrically accurate airway model was produced, and five other different airway models, each missing one or more specific anatomical features: the uvula, epiglottis, and/or soft palate, were derived from the original model. Hence, the geometrical boundaries of the six models were the same except at regions where specific anatomical structures were removed, and this was done to allow meaningful comparisons between the different geometries to be made using specific measurements. Spray-dried mannitol powder (volume median particle size and span were 3.22 μm and 1.90 μm, respectively) was loaded into a capsule-based dry powder inhaler with different resistance, an Osmohaler™ (low resistance), or Handihaler® (high resistance), attached to the inlet of the airway model, which its outlet was connected to a Next-Generation Impactor (NGI). The studies were performed using flow rates of 30 and 60 LPM. High-performance liquid chromatography (HPLC) was used to quantify the mass deposition of particles in different stages of the NGI and airway replicas. Results from this study show that widening the space between the oral cavity and oropharynx, exemplified by one of the six replicas developed, significantly decreases upper airway deposition as well as increases the fine particle fraction. The case with the highest deposition (63.5%) occurred in the pharynx replica with the soft palate present (at 60 LPM with the Hanihaler), while the lowest deposition (26.0%) occurred in the replica without the soft palate and epiglottis (at 30 LPM with the Osmohaler). This study highlights that in addition to the resistance of the inhalers, their interactions with the human airway anatomical features are likely to play important roles in the subsequent lung dose. Results from this study are novel because while the effects of different inhaler resistance in a given airway replica is known, the effects contributed by specific pharynx anatomical features on particle transport behaviour have not been studied experimentally or reported on in the literature. This study shows that space adjacent to the soft palate affects particle deposition dramatically but the effect appears to be more significant when using the Handihaler and for the high flow rate cases.

Development of a Novel Bronchodilator Vaping Drug Delivery System Based on Thermal Degradation Properties.

This work aims to investigate bronchodilator delivery with the use of different vaping drug delivery systems (VDDS) by determining the dose equivalence delivered in relation to different references: a clinical jet nebulizer, a pMDI (pressurized metered dose inhaler) and a DPI (dry powder inhaler). Three different bronchodilators were used (terbutaline, salbutamol hemisulfate, ipratropium bromide). The e-liquids contained the active pharmaceutical ingredient (API) in powder form. Two different VDDS were tested (JUUL and a GS AIR 2 atomizer paired with a variable lithium-ion battery (i-stick TC 40 W), 1.5 ohm resistance, and 15 W power). Samples were collected using a glass twin impinger (GTI). High-performance liquid chromatography (HPLC) was used to quantify the drugs. A next-generation impactor (NGI) was used to measure the particle size distribution. Terbutaline emerged as the optimal API for bronchodilator delivery in both VDDS devices. It achieved the delivery of a respirable dose of 20.05 ± 4.2 µg/puff for GS AIR 2 and 2.98 ± 0.52 µg/puff for JUUL. With these delivered doses, it is possible to achieve a dose equivalence similar to that of a jet nebulizer and DPI, all while maintaining a reasonable duration, particularly with the GS AIR 2. This study is the first to provide evidence that vaping bronchodilators work only with appropriate formulation, vaping technology, and specific drugs, depending on their thermal degradation properties.

A counter-swirl design concept for dry powder inhalers

A swirling airflow is incorporated in several dry powder inhalers (DPIs) for effective powder de-agglomeration. This commonly requires the use of a flow-straightening grid in the DPI to reduce drug deposition loss caused by large lateral spreading of the emerging aerosol. Here, we propose a novel grid-free DPI design concept that improves the aerosol flow characteristics and reduces the aforementioned drug loss. The basis of this design is the implementation of a secondary airflow that swirls in the opposite direction (counter-swirl) to that of a primary swirling airflow. In-vitro deposition, computational fluid dynamics simulations and particle image velocimetry measurements are used to evaluate the counter-swirl DPI aerosol performance and flow characteristics.In comparison with a baseline-DPI that has only a primary swirling airflow, the counter-swirl DPI has 20% less deposition of the emitted drug dose in the induction port and pre-separator of a next generation impactor (NGI). This occurs as a result of the lower flow-swirl generated from the counter-swirl DPI which eliminates the axial reverse flow outside of the mouthpiece and substantially reduces lateral spreading in the exiting aerosol.Modifications to the counter-swirl DPI design were made to prevent drug loss from the secondary airflow tangential inlets, which involved the addition of wall perforations in the tangential inlets and the separation of the primary and secondary swirling airflows by an annular channel. These modified DPI devices were successful in that aspect but had higher flow-swirl than that in the counter-swirl DPI and thus had higher drug mass retained in the device and deposited in the induction port and pre-separator of the NGI. The fine particle fraction in the aerosols generated from all the counter-swirl-based DPIs and the baseline-DPI are found to be statistically similar to each other.

Understanding the impact of mannitol on physical stability and aerosolization of spray-dried protein powders for inhalation

Pulmonary delivery of protein-based therapeutics, including antibodies, is a promising option for treating respiratory diseases. Spray drying is a widely used method for producing dry powder formulations with mannitol being a commonly used excipient for these inhalation formulations. There is limited research available concerning the utilization of mannitol as an excipient in the spray drying of proteins and its impact on aerosol performance. This study highlights the importance to understand mannitol’s potential role and impact in this context. To investigate the impact of mannitol on physical stability and aerosolization of spray-dried protein formulations, bovine serum albumin (BSA) was employed as a model protein and formulated with different concentrations of mannitol via spray drying. The spray-dried solids were characterized for their particle size using Malvern mastersizer and aerodynamic particle size using next generation impactor (NGI). Additionally, the solids were characterized with solid-state Fourier-transform infrared spectroscopy (ssFTIR), powder X-ray diffraction (PXRD), scanning electron microscopy (SEM) and solid-state nuclear magnetic resonance spectroscopy (ssNMR) to analyze the change in their secondary structure, crystallinity, particle morphology, and protein-excipient interaction, respectively. Size exclusion chromatography (SEC) was used to investigate changes in monomer content resulting from storage under stressed condition of 40 °C. Protein formulations containing more than 33 % mannitol by weight showed crystallization tendencies, causing an increase in monomer loss over time. ssNMR data also showed mixing heterogeneity of BSA and mannitol in the formulations with high mannitol contents. Futhermore, fine particle fraction (FPF) was found to decrease over time for the formulations containing BSA: Mannitol in the ratios of 2:1, 1:2, and 1:5, due to particle agglomeration induced by crystallization of mannitol. This study underscores the significant influence of excipients such as mannitol on the aerosol performance and storage stability of spray-dried protein formulations.

Acceptance Testing of Used Cascade Impactor Stages Based on Pressure Drop Measurements in a Flow System Managed with a Critical Flow Venturi: Part II-Quantification of the Test Uncertainty Ratio for Pass/Fail Decision-Making under Pharmacopeial Constraints.

Background: The pressure drop at any cascade impactor stage is related to the open area of nozzles at that stage. Pressure drop measurement therefore can potentially test whether the nozzles of a given stage are within the range specified for continued use for testing of inhalable drug products. Previous such efforts, however, have been hindered by the measurement precision required for making a pass/fail decision about these used impactors. In this study, we articulate the error analysis for a pressure drop measurement system managed with a critical flow venturi (CFV) and show that the resultant uncertainty in the effective diameter of used Next Generation Impactor (NGI) and Andersen-type impactor stages is generally small compared to the specification range. This result enables the user to make a pass/fail decision regarding suitability for continued use. Methods: We develop the equations governing the relationship between stage pressure drop and the effective diameter of each stage of a used impactor. These equations show that pressure drop measurements can indicate only the change (if any) in the effective diameter between a previous measurement and the current measurement. Propagation-of-error principles therefore show that the uncertainty of both measurements affects the resulting uncertainty. Results: The test uncertainty ratio (analytical power) of a CFV-managed pressure drop measurement system exceeds six for all but stage one of the NGI and for stages -1 and -2 of the Andersen-type impactor. The stage-one nozzle of the NGI is readily qualified with a Class X pin. Conclusions: The CFV-managed flow system described in Part I is sufficiently precise to enable a decision to be made about whether used impactor nozzles are suitable for continued use for testing of registered inhalable drug products. Examination of the industrial viability of the technology will require long-term testing in real-world settings with comparison to optical inspection methods.

Preparing dry powder inhalation formulation of salbutamol sulfate using an ultrasonic atomizer device

Inhaled particles must possess certain morphological characteristics to ensure effective drug delivery to the targeted site in the lungs. A modified version of ultrasonic spray pyrolysis was employed to prepare salbutamol sulfate in the form of dry powder. A solution of salbutamol sulfate was atomized using ultrasonic nebulization, and the droplets were transformed into solid drug particles through exposure to high temperature airflow. The engineered salbutamol sulfate samples underwent physical characterization, including particle size, morphology, thermal behavior, and crystallinity analysis. The aerodynamic particle size distribution (APSD) and in vitro deposition of the dry powder inhalation formulation were assessed using the Next Generation Impactor (NGI). The salbutamol sulfate dry powder prepared by the ultrasonic atomizer exhibited an aerodynamic diameter ranging from 1 to 5 μm, as supported by the SEM images. X-ray diffraction (XRD) and differential scanning calorimetry (DSC) results showed a significant drop in the crystallinity of the engineered particles. Aerosolization performance studies demonstrated a fine particle fraction (FPF) value (below 5 μm) of 25% for the engineered salbutamol sulfate produced using the ultrasonic atomizer technique, which is acceptable for inhalation purposes. Based on the observed results, this newly introduced method appears to be suitable for producing dry powder formulations of different drugs, with a minimized need for the use of surfactants or stabilizers in the formulation.

Simultaneously determination of fine particle dose of vilanterol and fluticasone furoate for dry powder inhaler (DPI) by utilizing gradient elution in chromatography system

Vilanterol (VT) and fluticasone furoate (FF) are components recently used in dry powder inhaler (DPI) to be administrated for patients with respiratory diseases, such as asthma or chronic obstructive pulmonary disease (COPD). In the present study, an approach to an analytical procedure development and validation is presented. Next generation impactor (NGI) and high performance liquid chromatography (HPLC) with UV detector were applied to determine two compounds and fine particle dose (FPD) of each active ingredients in DPI. The most satisfying chromatographic separation was obtained on Poroshell SB C18 (100 mm × 4.6 mm, 2.7 µm) column applying gradient elution by phosphonate buffer and acetonitrile. VT and FF were detected on a UV detector at wavelength of 210 nm and 245 nm, respectively. Among various coating agents, 4% polyethylene glycol PEG 200 in acetone (w/v) was selected as the most effective. Although various physicochemical properties of VT and FF, the analytical procedure allows simultaneously determine two compounds at different wavelengths. Limit of quantitative (LOQ) of vilanterol and fluticasone furoate were determined as 0.049 µg/ml and 0.032 µg/ml, respectively, what is desirable to determine of FPD of active ingredients in microdoses in DPI. The analytical procedure was determined as linear and accurate in the range of LOQ – 2.5 µg/ml and LOQ – 10.0 µg/ml of VT and FF, respectively. The coefficient of determination (R2) was found to be 0.9999 and 1.000 for VT and FF, respectively.

Novel Nanoaggregates from Phoenix dactylifera (date palm) for Inhalational Management of Cystic Fibrosis Using Dry Powder Inhalers

PurposePhoenixdactylifera extracts have shown efficacy as antioxidants and antibacterials for the treatment of lung diseases; however, the choice of route of administration remains a problem. The use of natural antibacterial remedies for the management of cystic fibrosis (CF) is promising due to recurring bacterial resistance to current antibiotics. Dry powder inhalers (DPIs) have also been identified as a patient-friendly, noninvasive method for local delivery of drugs to the lungs. Therefore, this work, which is the first of its kind, aimed to formulate nanoparticles of date palm extracts as DPIs and evaluate their aerodynamic and antibacterial biofilm characteristics for the potential treatment of CF.MethodChitosan-based nanoparticles (CDN) comprising aqueous date fruit extract with increasing concentrations of chitosan (0.05, 0.1, and 0.2% w/v) were prepared. The in vitro aerosolization of the formulations was studied using a next-generation impactor (NGI), and good aerosolization profiles were achieved. The produced nanoparticles were characterized using FTIR and XRD to confirm physical properties and TEM and zeta sizer to confirm shape and size. The antimicrobial activity of CDN was evaluated using a Pseudomonas aeruginosa biofilm model cultured in an artificial sputum medium (ASM) mimicking cystic fibrosis conditions in the lungs.ResultsNanoparticles containing 0.05% w/v chitosan demonstrated the highest encapsulation efficiency (55.91%) and delivered the highest emitted dose (98.92%) and fine particle fraction (42.62%). CDN demonstrated the first-time-ever reported significant 3.3 log-cycle inhibition of P. aeruginosa biofilm cultured in ASM. TEM images revealed the formation of spherical particles with an average size of 42.98 ± 19.19 nm. FTIR and XRD studies demonstrated the compatibility of the components with the presence of the characteristic features of chitosan and date powder.ConclusionsThis novel work showcases CDN as a prophylactic adjuvant for the management of cystic fibrosis using DPI.