Assessment of Dry Powder Inhaler Carrier Targeted Design: A Comparative Case Study of Diverse Anomeric Compositions and Physical Properties of Lactose

Treatment of Idiopathic Pulmonary Fibrosis by Inhaled Silybin Dry Powder Prepared via the Nanosuspension Spray Drying Technology

Idiopathic pulmonary fibrosis (IPF) is a kind of life-threatening interstitial lung disease characterized by progressive dyspnea with accurate pathogenesis unknown. At present, heat shock protein inhibitors are gradually used to treat IPF. Silybin, a heat shock protein C-terminal inhibitor, has high safety and good application prospects. In this work, we have developed a silybin powder able to be used for inhalation administration for the treatment of IPF. Silybin powder was prepared by the spray drying method and identified using cascade impactometry, particle size, scanning electron microscopy (SEM), differential scanning calorimetry (DSC), X-ray diffraction (XRD), and Fourier transform infrared (FT-IR) spectroscopy. A rat model of bleomycin-induced IPF was used to assess the effect of inhaled silybin spray-dried powder. Lung hydroxyproline content, wet weight, histology, inflammatory factor expression, and gene expression were examined. The results showed that inhaled silybin spray-dried powder alleviated inflammation and fibrosis, limited hydroxyproline accumulation in the lungs, modulated gene expression in the development of IPF, and improved postoperative survival. The results of this study suggest that silybin spray-dried powder is an attractive candidate for the treatment of IPF.

Investigation on the Influence of Design Features on the Performance of Dry Powder Inhalers: Spiral Channel, Mouthpiece Dimension, and Gas Inlet

As inhaler design is rarely studied but critically important in pulmonary drug delivery, this study investigated the influence of inhaler designs, including a novel spiral channel, mouthpiece dimensions (diameter and length) as well as gas inlet. Experimental dispersion of a carrier-based formulation in conjugation with computational fluid dynamics (CFD) analysis, was performed to determine how the designs affect inhaler performance. Results reveal that inhalers with a narrow spiral channel could effectively increase drug-carrier detachment by introducing high velocity and strong turbulent flow in the mouthpiece, although the drug retention in the device is significantly high. It is also found that reducing mouthpiece diameter and gas inlet size could greatly improve the fine particle dose delivered to the lungs, whereas the mouthpiece length plays a trivial influence on the aerosolization performance. This study contributes toward a better understanding of inhaler designs as relevant to overall inhaler performance, and sheds light on how the designs affect device performance.

Impact of Different Saccharides on the In-Process Stability of a Protein Drug During Evaporative Drying: From Sessile Droplet Drying to Lab-Scale Spray Drying

OBJECTIVES

Solid biopharmaceutical products can circumvent lower temperature storage and transport and increase remote access with lower carbon emissions and energy consumption. Saccharides are known stabilizers in a solid protein produced via lyophilization and spray drying (SD). Thus, it is essential to understand the interactions between saccharides and proteins and the stabilization mechanism.

METHODS

A miniaturized single droplet drying (MD) method was developed to understand how different saccharides stabilize proteins during drying. We applied our MD to different aqueous saccharide-protein systems and transferred our findings to SD.

RESULTS

The poly- and oligosaccharides tend to destabilize the protein during drying. The oligosaccharide, Hydroxypropyl β-cyclodextrin (HPβCD) shows high aggregation at a high saccharide-to-protein molar ratio (S/P ratio) during MD, and the finding is supported by nanoDSF results. The polysaccharide, Dextran (DEX) leads to larger particles, whereas HPBCD leads to smaller particles. Furthermore, DEX is not able to stabilize the protein at higher S/P ratios either. In contrast, the disaccharide Trehalose Dihydrate (TD) does not increase or induce protein aggregation during the drying of the formulation. It can preserve the protein's secondary structure during drying, already at low concentrations.

CONCLUSION

During the drying of S/P formulations containing the saccharides TD and DEX, the MD approach could anticipate the in-process (in) stability of protein X at laboratory-scale SD. In contrast, for the systems with HPβCD, the results obtained by SD were contradictory to MD. This underlines that depending on the drying operation, careful consideration needs to be applied to the selection of saccharides and their ratios.

Temperature cycling-induced formation of crystalline coatings

The surface of particles is the hotspot of interaction with their environment and is therefore a major target for particle engineering. Particles with tailored coatings are greatly desired for a range of different applications. Amorphous coatings applied via film coating or microencapsulation have frequently been described in the pharmaceutical context and usually result in homogeneous surfaces. In the present study we have been exploring the feasibility of coating core particles with crystalline substances, a matter that has rarely been investigated. The expansion of the range of possible coating materials to include small organic molecules enables completely new product properties to be achieved. We present an approach based on temperature cycles performed in a tubular crystallizer to result in engineered crystalline coatings on excipient core particles. By manipulating the process settings and by the choice of coating substance we are able to tailor surface roughness, topography as well as surface chemistry. Benefits of our approach are demonstrated by using resulting particles as carriers in dry-powder-inhaler formulations. Depending on the resulting surface chemistry and surface roughness, coated carrier particles show varying fitness for delivering the model API salbutamol sulphate to the lung.

Development of a Workflow to Engineer Tailored Microparticles Via Inkjet Printing

PURPOSE

New drug development and delivery approaches result in an ever-increasing demand for tailored microparticles with defined sizes and structures. Inkjet printing technologies could be promising new processes to engineer particles with defined characteristics, as they are created to precisely deliver liquid droplets with high uniformity.

METHODS

D-mannitol was used as a model compound alone or co-processed with the pore former agent ammonium bicarbonate, and the polymer polyethylene glycol 200. Firstly, a drop shape analyzer was used to characterize and understand ink/substrate interactions, evaporation, and solidification kinetics. Consequently, the process was transferred to a laboratory-scale inkjet printer and the resulting particles collected, characterized and compared to others obtained via an industrial standard technique.

RESULTS

The droplet shape analysis allowed to understand how 3D structures are formed and helped define the formulation and process parameters for inkjet printing. By adjusting the drop number and process waveform, spherical particles with a mean size of approximately 100 µm were obtained. The addition of pore former and polymer allowed to tailor the crystallization kinetics, resulting in particles with a different surface (i.e., spike-like surface) and bulk (e.g. porous and non-porous) structure.

CONCLUSION

The workflow described enabled the production of 3D structures via inkjet printing, demonstrating that this technique can be a promising approach to engineer microparticles.

Recent developments in lactose blend formulations for carrier-based dry powder inhalation

Lactose is the most commonly used excipient in carrier-based dry powder inhalation (DPI) formulations. Numerous inhalation therapies have been developed using lactose as a carrier material. Several theories have described the role of carriers in DPI formulations. Although these theories are valuable, each DPI formulation is unique and are not described by any single theory. For each new formulation, a specific development trajectory is required, and the versatility of lactose can be exploited to optimize each formulation. In this review, recent developments in lactose-based DPI formulations are discussed. The effects of varying the material properties of lactose carrier particles, such as particle size, shape, and morphology are reviewed. Owing to the complex interactions between the particles in a formulation, processing adhesive mixtures of lactose with the active ingredient is crucial. Therefore, blending and filling processes for DPI formulations are also reviewed. While the role of ternary agents, such as magnesium stearate, has increased, lactose remains the excipient of choice in carrier-based DPI formulations. Therefore, new developments in lactose-based DPI formulations are crucial in the optimization of inhalable medicine performance.

Probing Critical Physical Properties of Lactose-Polyethylene Glycol Microparticles in Pulmonary Delivery of Chitosan Nanoparticles

Pulmonary delivery of chitosan nanoparticles is met with nanoparticle agglomeration and exhalation. Admixing lactose-based microparticles (surface area-weighted diameter~5 μm) with nanoparticles mutually reduces particle agglomeration through surface adsorption phenomenon. Lactose-polyethylene glycol (PEG) microparticles with different sizes, morphologies and crystallinities were prepared by a spray drying method using varying PEG molecular weights and ethanol contents. The chitosan nanoparticles were similarly prepared. In vitro inhalation performance and peripheral lung deposition of chitosan nanoparticles were enhanced through co-blending with larger lactose-PEG microparticles with reduced specific surface area. These microparticles had reduced inter-microparticle interaction, thereby promoting microparticle–nanoparticle interaction and facilitating nanoparticles flow into peripheral lung.

Pinto J, Paudel A. Understanding Carrier Performance in Low-Dose Dry Powder Inhalation: An In Vitro-In Silico Approach

The use of physiologically based pharmacokinetic (PBPK) models to support drug product development has become increasingly popular. The in vitro characterization of the materials of the formulation provides valuable descriptors for the in silico prediction of the drug’s pharmacokinetic profile. Thus, the application of an in vitro–in silico framework can be decisive towards the prediction of the in vivo performance of a new medicine. By applying such an approach, this work aimed to derive mechanistic based insights into the potential impact of carrier particles and powder bulk properties on the in vivo performance of a lactose-based dry powder inhaler (DPI). For this, a PBPK model was developed using salbutamol sulphate (SS) as a model drug and the in vitro performance of its low-dose blends (2% w/w) with different types of lactose particles was investigated using different DPI types (capsule versus reservoir) at distinct airflows. Likewise, the influence of various carrier’s particle and bulk properties, device type and airflow were investigated in silico. Results showed that for the capsule-based device, low-dose blends of SS had a better performance, when smaller carrier particles (Dv_0.5 ≈ 50 μm) with about 10% of fines were used. This resulted in a better predicted bioavailability of the drug for all the tested airflows. For the reservoir type DPI, the mean particle size (Dv_0.5) was identified as the critical parameter impacting performance. Shear cell and air permeability or compressibility measurements, particle size distribution by pressure titration and the tensile strength of the selected lactose carrier powders were found useful to generate descriptors that could anticipate the potential in vivo performance of the tested DPI blends.

Spherical agglomerates of lactose as potential carriers for inhalation

We report here on spherical lactose agglomerates as potential carriers for inhalation applications. Micromeritic properties of three spherical lactose agglomerates (SA-A, SA-B, SA-C) and a standard lactose inhalation grade carrier (Lactohale 100; LH100) were evaluated and compared. Ordered mixtures with micronized salbutamol sulfate as the model active pharmaceutical ingredient (API) and lactose carriers at two drug loadings (2 wt%, 5 wt%) were prepared, and in-vitro aerosolization performance was assessed. The spherical crystallization process led to particles with tailored micromeritic properties. These had larger specific surface area and greater fine fraction < 10 µm, compared to LH100, due to their coarse morphology. Their properties were reflected in the flowability parameters, where two types of spherical agglomerates of lactose showed more cohesive behavior compared to the other lactose grades. Blend uniformity showed improved homogeneous distribution of the API at higher drug load. In-vitro aerosolization tests showed that the spherical agglomerates of lactose enhanced the dose of API, compared to LH100. SA-B and SA-C showed significantly higher fine particle fractions at low drug load compared to the others, whereas overall, the largest fine particle fraction was for SA-B at high drug load. The carrier material attributes related to particle size, specific surface area, compressibility, flowability (cohesion, flow function), and air permeability were critical for aerosolization performance.

A review on chitosan and its development as pulmonary particulate anti-infective and anti-cancer drug carriers

Chitosan, as a biodegradable and biocompatible polymer, is characterized by anti-microbial and anti-cancer properties. It lately has received a widespread interest for use as the pulmonary particulate backbone materials of drug carrier for the treatment of infectious disease and cancer. The success of chitosan as pulmonary particulate drug carrier is a critical interplay of their mucoadhesive, permeation enhancement and site/cell-specific attributes. In the case of nanocarriers, various microencapsulation and micro-nano blending systems have been devised to equip them with an appropriate aerodynamic character to enable efficient pulmonary aerosolization and inhalation. The late COVID-19 infection is met with acute respiratory distress syndrome and cancer. Chitosan and its derivatives are found useful in combating HCoV and cancer as a function of their molecular weight, substituent type and its degree of substitution. The interest in chitosan is expected to rise in the next decade from the perspectives of drug delivery in combination with its therapeutic performance.

A Systematic Safety Evaluation of Nanoporous Mannitol Material as a Dry-Powder Inhalation Carrier System

For carrier-based dry-powder inhaler (DPI) formulations, the adhesion between carrier particles and active pharmaceutical ingredients (API) particles have a significant influence on the aerosolization performance of the API-carrier complexes and the desired detachment of the API for efficient pulmonary delivery. In our previous study, nanoporous mannitol material was successfully fabricated as carriers by a one-step nonorganic solvent spray drying method with the thermal degradation of ammonium carbonate. These carriers were shown to achieve excellent aerosolization performance. In addition, no residue of ammonium carbonate was detected on the powder surface. However, the safety of nanoporous mannitol carriers (Nano-PMCs) during pulmonary administration/delivery was still unknown because the lung is vulnerable to the inhaled particles. To address this question, the present study was conducted to construct a systematic safety evaluation for DPIs carriers to investigate the safety of Nano-PMCs in the whole inhalation, which would make up for the lack of detailed and standardized method in this field. In vitro safety evaluation was carried out using respiratory and pulmonary cytotoxicity tests, hemolysis assay, and ciliotoxicity test. In vivo safety evaluation was studied by measuring inflammatory indicators in the bronchoalveolar lavage fluid, assessing the pulmonary function and observing pulmonary pathological changes. Nano-PMCs showed satisfactory biocompatibility on respiratory tracts and lungs in vitro and in vivo. It was suggested that Nano-PMCs were safe for intrapulmonary delivery and potential as DPI carriers.

Microstructural characterization of carrier-based dry powder inhalation excipients: Insights and guidance

The growing interest in development of dry powder inhalation (DPI) products raises a need for development of standard testing methods and specifications for DPI excipients. The pharmaceutical industry, meanwhile, yet lacks compendial guidance on this topic. Despite of the complexity of interactions taking place in DPI systems and the large number and variety of interplaying factors, understanding of key determinants of performance (critical quality attributes) of DPI excipients have considerably developed over the past years. In light of the current knowledge in this area, this article provides technical guidance and insights on testing and quality control of carrier-based-DPI excipients. These excipients are, typically, blends of coarse, carrier particles and fine, performance-modulating particles. The article explores techniques used for measurement of key microstructural attributes, namely the particle size distribution, the porosity and the particle surface roughness, the particle shape, rheological properties, and the permeability, of these excipients. The technical relevance of each measurement to the functionality of the excipients is critically discussed. In this regard, caveats concerning use of some measurements and data analysis procedures are raised. The guidance lends itself for compendial adoption.

Targeting oxidative stress using tri-needle electrospray engineered Ganoderma lucidum polysaccharide-loaded porous yolk-shell particles

Chronic lung diseases (e.g. chronic obstructive pulmonary disease and asthma) are associated with oxidative stress and common treatments include various types of inhalation therapies. In this work Ganoderma lucidum polysaccharide (GLP), a naturally occurring antioxidant is loaded into porous Poly (ε-caprolactone) (PCL) particles using a single step tri-needle coaxial electrospray process (Tri-needle CES); with a view to develop therapies to combat oxidative stress. Based on the core-shell structure of porous yolk shell particles (YSPs), GLP-loaded YSPs displayed a bi-phasic release pattern. In vitro cell studies indicate GLP-loaded porous YSPs display good biocompatibility and positive attributes towards H₂O₂-induced oxidative stress in MRC-5 cells and dramatically attenuate intracellular reactive oxygen species (ROS) levels as well as significantly increase cell viability. In vivo inhalation studies indicate that GLP-loaded porous YSPs can be delivered to deep lung tissue and remain deposited for over 48 h and are subsequently removed by natural clearance mechanisms. Based on current findings GLP-loaded porous YSPs are suitable for pulmonary delivery and display good inhalation therapy potential to treat chronic lung diseases.