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Thoma T, Ma-Hock L, Schneider S, Honarvar N, Treumann S, Groeters S, Strauss V, Marxfeld H, Funk-Weyer D, Seiffert S, Wohlleben W, Dammann M, Wiench K, Lombaert N, Spirlet C, Vasquez M, Dewhurst N, Landsiedel R. Toxicological inhalation studies in rats to substantiate grouping of zinc oxide nanoforms. Part Fibre Toxicol 2024; 21:24. [PMID: 38760761 PMCID: PMC11100124 DOI: 10.1186/s12989-024-00572-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2023] [Accepted: 02/24/2024] [Indexed: 05/19/2024] Open
Abstract
BACKGROUND Significant variations exist in the forms of ZnO, making it impossible to test all forms in in vivo inhalation studies. Hence, grouping and read-across is a common approach under REACH to evaluate the toxicological profile of familiar substances. The objective of this paper is to investigate the potential role of dissolution, size, or coating in grouping ZnO (nano)forms for the purpose of hazard assessment. We performed a 90-day inhalation study (OECD test guideline no. (TG) 413) in rats combined with a reproduction/developmental (neuro)toxicity screening test (TG 421/424/426) with coated and uncoated ZnO nanoforms in comparison with microscale ZnO particles and soluble zinc sulfate. In addition, genotoxicity in the nasal cavity, lungs, liver, and bone marrow was examined via comet assay (TG 489) after 14-day inhalation exposure. RESULTS ZnO nanoparticles caused local toxicity in the respiratory tract. Systemic effects that were not related to the local irritation were not observed. There was no indication of impaired fertility, developmental toxicity, or developmental neurotoxicity. No indication for genotoxicity of any of the test substances was observed. Local effects were similar across the different ZnO test substances and were reversible after the end of the exposure. CONCLUSION With exception of local toxicity, this study could not confirm the occasional findings in some of the previous studies regarding the above-mentioned toxicological endpoints. The two representative ZnO nanoforms and the microscale particles showed similar local effects. The ZnO nanoforms most likely exhibit their effects by zinc ions as no particles could be detected after the end of the exposure, and exposure to rapidly soluble zinc sulfate had similar effects. Obviously, material differences between the ZnO particles do not substantially alter their toxicokinetics and toxicodynamics. The grouping of ZnO nanoforms into a set of similar nanoforms is justified by these observations.
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Affiliation(s)
| | - Lan Ma-Hock
- BASF SE, Experimental Toxicology and Ecology, Ludwigshafen am Rhein, Germany
| | - Steffen Schneider
- BASF SE, Experimental Toxicology and Ecology, Ludwigshafen am Rhein, Germany
| | - Naveed Honarvar
- BASF SE, Experimental Toxicology and Ecology, Ludwigshafen am Rhein, Germany
| | - Silke Treumann
- BASF SE, Experimental Toxicology and Ecology, Ludwigshafen am Rhein, Germany
| | - Sibylle Groeters
- BASF SE, Experimental Toxicology and Ecology, Ludwigshafen am Rhein, Germany
| | - Volker Strauss
- BASF SE, Experimental Toxicology and Ecology, Ludwigshafen am Rhein, Germany
| | - Heike Marxfeld
- BASF SE, Experimental Toxicology and Ecology, Ludwigshafen am Rhein, Germany
| | - Dorothee Funk-Weyer
- BASF SE, Experimental Toxicology and Ecology, Ludwigshafen am Rhein, Germany
| | - Svenja Seiffert
- BASF SE, Analytical and Material Science, Ludwigshafen am Rhein, Germany
| | - Wendel Wohlleben
- BASF SE, Analytical and Material Science, Ludwigshafen am Rhein, Germany
| | - Martina Dammann
- BASF SE, Experimental Toxicology and Ecology, Ludwigshafen am Rhein, Germany
| | - Karin Wiench
- BASF SE, Product Stewardship, Regulatory Toxicology Chemicals, Ludwigshafen am Rhein, Germany
| | | | | | | | | | - Robert Landsiedel
- BASF SE, Experimental Toxicology and Ecology, Ludwigshafen am Rhein, Germany.
- Pharmacy, Pharmacology and Toxicology, Free University of Berlin, Berlin, Germany.
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Dahmash EZ, Achkar NR, Ali DK, Jarrar Q, Iyire A, Assaf SM, Alyami H. Preclinical evaluation of novel synthesised nanoparticles based on tyrosine poly(ester amide) for improved targeted pulmonary delivery. Sci Rep 2024; 14:9845. [PMID: 38684750 PMCID: PMC11058873 DOI: 10.1038/s41598-024-59588-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2024] [Accepted: 04/12/2024] [Indexed: 05/02/2024] Open
Abstract
Fixed dose combinations (FDCs) incorporating two or three medicines in a single inhaler have been created to enhance patient compliance and hence clinical outcomes. However, the development of dry powder inhalers (DPIs), particularly for FDCs, faces challenges pertinent to formulation uniformity and reproducibility. Therefore, this project aimed to employ nanotechnology to develop a FDC of DPIs for market-leading medicines-fluticasone propionate (FP) and salmeterol xinafoate (SAL)-for asthma management. Nanoaggregates were prepared using a novel biocompatible and biodegradable poly(ester amide) based on the amino acid tyrosine, utilising a one-step interfacial polymerisation process. The produced tyrosine poly (ester amide) drug-loaded nanoparticles were evaluated for content uniformity, PSA, FTIR, TEM, DSC, XRD and aerodynamic performance (in vitro and in vivo). The optimised formulation demonstrated high entrapment efficiency- > 90%. The aerodynamic performance in terms of the emitted dose, fine particle fraction and respirable dose was superior to the carrier-based marketed product. In-vivo studies showed that FP (above the marketed formulation) and SAL reached the lungs of mice in a reproducible manner. These results highlight the superiority of novel FDC FP/SAL nanoparticles prepared via a one-step process, which can be used as a cost-effective and efficient method to alleviate the burden of asthma.
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Affiliation(s)
- Eman Zmaily Dahmash
- Department of Chemistry and Pharmaceutical Sciences, School of Life Sciences, Pharmacy and Chemistry, Kingston University, London, KT1 2EE, UK.
| | - Nour Radwan Achkar
- Department of Applied Pharmaceutical Sciences and Clinical Pharmacy, Faculty Pharmacy, Isra University, Amman, 11622, Jordan
| | - Dalia Khalil Ali
- Department of Physiotherapy, Faculty of Allied Medical Sciences, Isra University, Amman, 11622, Jordan
| | - Qais Jarrar
- Department of Applied Pharmaceutical Sciences and Clinical Pharmacy, Faculty Pharmacy, Isra University, Amman, 11622, Jordan
| | - Affiong Iyire
- Aston Pharmacy School, College of Health & Life Sciences, Aston University, Birmingham, B4 7ET, UK
| | - Shereen M Assaf
- Department of Pharmaceutical Technology, Faculty of Pharmacy, Jordan University of Science and Technology, P. O. Box 3030, Irbid, 22110, Jordan
| | - Hamad Alyami
- Department of Pharmaceutics, College of Pharmacy, Najran University, 55461, Najran, Saudi Arabia
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Xu Y, Li H, Sun N, Yao B, Dai W, Wang J, Si S, Liu S, Jiang L. Dry Powder Formulations for Inhalation Require a Smaller Aerodynamic Diameter for Usage at High Altitude. J Pharm Sci 2023; 112:2655-2666. [PMID: 37595750 DOI: 10.1016/j.xphs.2023.08.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2023] [Revised: 08/14/2023] [Accepted: 08/14/2023] [Indexed: 08/20/2023]
Abstract
BACKGROUND High Altitude Pulmonary Edema (HAPE) seriously threatens the health of people at high altitudes. There are drug treatments for HAPE, and dry powder formulations (DPFs) represent a rapid and accessible delivery vehicle for these drugs. However, there are presently no reports on the inhalability of DPFs in low-pressure environments. Given the reduced atmospheric pressure typical at high altitudes, conventional DPFs might not be suitable for inhalation. Therefore, it is necessary to elucidate the deposition behaviors of dry powder in the respiratory tract at low pressure, as well as to improve their pulmonary deposition efficiency via adjustments to their formulation and design. METHODS The effect of air pressure, inspiratory velocity, and particle properties (such as size, density, and aerodynamic diameter) on pulmonary deposition of DPFs was calculated by a computational fluid dynamics (CFD)-coupled discrete phase model. DPFs of various aerodynamic diameters were prepared by spray drying, and the inhalability of these DPFs in a low-pressure environment was evaluated in mice. Finally, a mouse model of HAPE was established, and the treatment of HAPE by nifedipine-loaded DPFs with small aerodynamic diameter was validated. RESULTS CFD results showed that low pressure decreased the deposition of DPFs in the lungs. At 0.5 standard atmosphere, DPFs with aerodynamic diameter of ∼2.0 μm could not enter the lower respiratory tract; however, a decrease in the physical diameter, density, and, consequently, the aerodynamic diameter of the DPFs was able to enhance pulmonary deposition of these powders. To validate the CFD results, three kinds of dry powder with aerodynamic diameters of 0.66, 0.98, and 2.00 μm were prepared by spray drying. Powders with smaller aerodynamic diameter could be inhaled into the lungs of mice more effectively, and, consequently could ameliorate the progression of HAPE more effectively than conventional powders. These results were consistent with the CFD results. CONCLUSIONS Low atmospheric pressure can prevent the pulmonary deposition of DPFs at high altitudes. Compared with conventional DPFs, powders with smaller aerodynamic diameter can be effectively inhaled at these pressures and thus might be more suitable for the treatment the HAPE.
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Affiliation(s)
- Ya Xu
- School of Pharmacy, Xuzhou Medical University, Xuzhou 221009, China
| | - Huiyang Li
- School of Pharmacy, Xuzhou Medical University, Xuzhou 221009, China
| | - Nan Sun
- School of Pharmacy, Xuzhou Medical University, Xuzhou 221009, China; The Affiliated Lianyungang Oriental Hospital of Xuzhou Medical University, Lianyungang 222042, China
| | - Bingmei Yao
- School of Pharmacy, Xuzhou Medical University, Xuzhou 221009, China
| | - Wenjin Dai
- School of Pharmacy, Xuzhou Medical University, Xuzhou 221009, China
| | - Jian Wang
- School of Pharmacy, Xuzhou Medical University, Xuzhou 221009, China
| | - Sujia Si
- School of Pharmacy, Xuzhou Medical University, Xuzhou 221009, China
| | - Shuo Liu
- School of Pharmacy, Xuzhou Medical University, Xuzhou 221009, China
| | - Liqun Jiang
- School of Pharmacy, Xuzhou Medical University, Xuzhou 221009, China.
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Azam S, Kurashov V, Golbeck JH, Bhattacharyya S, Zheng S, Liu S. Comparative 6+studies of environmentally persistent free radicals on nano-sized coal dusts. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 878:163163. [PMID: 37003338 DOI: 10.1016/j.scitotenv.2023.163163] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2023] [Revised: 03/23/2023] [Accepted: 03/26/2023] [Indexed: 05/13/2023]
Abstract
Coal dust is the major hazardous pollutant in the coal mining environment. Recently environmentally persistent free radicals (EPFRs) were identified as one of the key characteristics which could impart toxicity to the particulates released into the environment. The present study used Electron Paramagnetic Resonance (EPR) spectroscopy to analyze the characteristics of EPFRs present in different types of nano-size coal dust. Further, it analyzed the stability of the free radicals in the respirable nano-size coal dust and compared their characteristics in terms of EPR parameters (spin counts and g-values). It was found that free radicals in coal are remarkably stable (can remain intact for several months). Also, Most of the EPFRs in the coal dust particles are either oxygenated carbon centered or a mixture of carbon and oxygen-centered free radicals. EPFRs concentration in the coal dust was found to be proportional to the carbon content of coal. The characteristic g-values were found to be inversely related to the carbon content of coal dust. The spin concentrations in the lignite coal dust were between 3.819 and 7.089 μmol/g, whereas the g-values ranged from 2.00352 to 2.00363. The spin concentrations in the bituminous coal dust were between 11.614 and 25.562 μmol/g, whereas the g-values ranged from 2.00295 to 2.00319. The characteristics of EPFRs present in coal dust identified by this study are similar to the EPFRs, which were found in other environmental pollutants such as combustion-generated particulates, PM2.5, indoor dust, wildfires, biochar, haze etc., in some of the previous studies. Considering the toxicity analysis of environmental particulates containing EPFRs similar to those identified in the present study, it can be confidently hypothesized that the EPFRs in the coal dust might play a major role in modulating the coal dust toxicity. Hence, it is recommended that future studies should analyze the role of EPFR-loaded coal dust in mediating the inhalation toxicity of coal dust.
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Affiliation(s)
- Sikandar Azam
- Department of Energy and Mineral Engineering, G(3) Center and Energy Institute, The Pennsylvania State University, University Park, PA 16802, USA
| | - Vasily Kurashov
- Department of Chemistry, Pennsylvania State University, University Park, PA 16802, USA
| | - John H Golbeck
- Department of Chemistry, Pennsylvania State University, University Park, PA 16802, USA
| | - Sekhar Bhattacharyya
- Department of Energy and Mineral Engineering, G(3) Center and Energy Institute, The Pennsylvania State University, University Park, PA 16802, USA
| | - Siyang Zheng
- Department of Biomedical Engineering, College of Engineering, Carnegie Mellon University, 15213, USA
| | - Shimin Liu
- Department of Energy and Mineral Engineering, G(3) Center and Energy Institute, The Pennsylvania State University, University Park, PA 16802, USA.
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Tanprasert S, Kampeewichean C, Shiratori S, Piemjaiswang R, Chalermsinsuwan B. Non-spherical drug particle deposition in human airway using computational fluid dynamics and discrete element method. Int J Pharm 2023; 639:122979. [PMID: 37100258 DOI: 10.1016/j.ijpharm.2023.122979] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2022] [Revised: 04/05/2023] [Accepted: 04/19/2023] [Indexed: 04/28/2023]
Abstract
Currently, the air pollution and the respiratory disease problems that affect human health are increasing rapidly. Hence, there is attention for trend prediction of the located deposition of inhaled particles. In this study, Weibel's based human airway model (G0-G5) was employed. The computational fluid dynamics and discrete element method (CFD-DEM) simulation was successfully validated by comparison to the previous research studies. The CFD-DEM achieves a better balance between numerical accuracy and computational requirement when comparing with the other methods. Then, the model was used to analyze the non-spherical drug transport with different drug particle sizes, shapes, density, and concentrations. The results found that all the studied factors affected the drug deposition and particle out-mass percentage except the drug concentration. The drug deposition was increased with the increasing of particle size and particle density due to the influence of particle inertia. The Tomahawk-shaped drug deposited easier than the cylindrical drug shape because of the different drag behavior. For the effect of airway geometries, G0 was the maximum deposited zone and G3 was the minimum deposited zone. The boundary layer was found around bifurcation due to the shear force at the wall. Finally, the knowledge can give an essential recommendation for curing patients with pharmaceutical aerosol. The design suggestion of a proper drug delivery device can be summarized.
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Affiliation(s)
- Sorathan Tanprasert
- Fuels Research Center, Department of Chemical Technology, Faculty of Science, Chulalongkorn University, 254 Phayathai Road, Wangmai, Pathumwan, Bangkok 10330, Thailand
| | - Chanida Kampeewichean
- Fuels Research Center, Department of Chemical Technology, Faculty of Science, Chulalongkorn University, 254 Phayathai Road, Wangmai, Pathumwan, Bangkok 10330, Thailand
| | - Shuichi Shiratori
- Division of Nuclear Medicine, Department of Radiology, Faculty of Medicine, Siriraj Hospital, Mahidol University, Bangkok, 10700, Thailand
| | - Ratchanon Piemjaiswang
- Environmental Research Institute, Chulalongkorn University, Institute Building 2, 254 Phayathai Road, Wangmai, Pathumwan, Bangkok, 10330, Thailand
| | - Benjapon Chalermsinsuwan
- Fuels Research Center, Department of Chemical Technology, Faculty of Science, Chulalongkorn University, 254 Phayathai Road, Wangmai, Pathumwan, Bangkok 10330, Thailand; Center of Excellence on Petrochemical and Materials Technology, Chulalongkorn University, 254 Phayathai Road, Wangmai, Pathumwan, Bangkok 10330, Thailand; Advanced Computational Fluid Dynamics Research Unit, Chulalongkorn University, 254 Phayathai Road, Wangmai, Pathumwan, Bangkok 10330, Thailand.
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Ma H, Zhou L, Liu Z, Chen M, Xia X, Zhao Y. A review of recent development for the CFD-DEM investigations of non-spherical particles. POWDER TECHNOL 2022. [DOI: 10.1016/j.powtec.2022.117972] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
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Lu D, Fatehi P. Interaction of rough ellipsoidal particles with random surface asperities in colloidal systems. Chem Eng Sci 2022. [DOI: 10.1016/j.ces.2022.117869] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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Wang Y, Yin Z, Bao F, Shen J. CFD-DEM Coupling Model for Deposition Process Analysis of Ultrafine Particles in a Micro Impinging Flow Field. MICROMACHINES 2022; 13:mi13071110. [PMID: 35888927 PMCID: PMC9323935 DOI: 10.3390/mi13071110] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/17/2022] [Revised: 07/09/2022] [Accepted: 07/11/2022] [Indexed: 02/01/2023]
Abstract
Gas with ultrafine particle impaction on a solid surface is a unique case of curvilinear motion that can be widely used for the devices of surface coatings or instruments for particle size measurement. In this work, the Eulerian–Lagrangian method was applied to calculate the motion of microparticles in a micro impinging flow field with consideration of the interactions between particle to particle, particle to wall, and particle to fluid. The coupling computational fluid dynamics (CFD) with the discrete element method (DEM) was employed to investigate the different deposition patterns of microparticles. The vortex structure and two types of particle deposits (“halo” and “ring”) have been discussed. The particle deposition characteristics are affected both by the flow Reynolds number (Re) and Stokes number (stk). Moreover, two particle deposition patterns have been categorized in terms of Re and stk. Finally, the characteristics and mechanism of particle deposits have been analyzed using the particle inertia, the process of impinging (particle rebound or no rebound), vortical structures, and the kinetic energy conversion in two-phase flow, etc.
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Respirable Coal Mine Dust: A Review of Respiratory Deposition, Regulations, and Characterization. MINERALS 2021. [DOI: 10.3390/min11070696] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
In the late 1990s, despite years of efforts to understand and reduce coal worker’s pneumoconiosis (CWP) prevalence from more than 30% in 1970 to less than 4.2%, the level of occurrence among the US coal miners increased unexpectedly. The recent resurgence of lung diseases has raised concerns in the scientific and regulatory communities. In 2014, the United States Mine Safety and Health Administration (MSHA) issued a new dust rule changing the respirable coal mine dust (RCMD) exposure limits, measurement technology, and sampling protocol. The analysis for probable causes for the substantial increase in the CWP incidence rate is rather complicated. This paper aims to conduct a review of RCMD respiratory deposition, health effects, monitoring, regulations, and particle characteristics. The primary sources of RCMD along with the health risks from potential exposure are highlighted, and the current RCMD exposure regulations of the major coal producer countries are compared. A summary of RCMD characterization studies from 1972 to the present is provided. A review of the literature revealed that numerous factors, including geological and mining parameters, advancements in mining practices, particle characteristics, and monitoring approaches are considered to contribute to the recent resurgence of RCMD lung diseases. However, the root causes of the problem are still unknown. The effectiveness of the new dust rules in the United States will probably take years to be correctly assessed. Therefore, future research is needed to understand the relationship between RCMD particle characteristics and lung deposition, and the efficacy of current monitoring practices to measure the true dose of RCMD exposure.
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Zheng Z, Leung SSY, Gupta R. Flow and Particle Modelling of Dry Powder Inhalers: Methodologies, Recent Development and Emerging Applications. Pharmaceutics 2021; 13:189. [PMID: 33535512 PMCID: PMC7912775 DOI: 10.3390/pharmaceutics13020189] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2020] [Revised: 01/22/2021] [Accepted: 01/27/2021] [Indexed: 11/16/2022] Open
Abstract
Dry powder inhaler (DPI) is a device used to deliver a drug in dry powder form to the lungs. A wide range of DPI products is currently available, with the choice of DPI device largely depending on the dose, dosing frequency and powder properties of formulations. Computational fluid dynamics (CFD), together with various particle motion modelling tools, such as discrete particle methods (DPM) and discrete element methods (DEM), have been increasingly used to optimise DPI design by revealing the details of flow patterns, particle trajectories, de-agglomerations and depositions within the device and the delivery paths. This review article focuses on the development of the modelling methodologies of flow and particle behaviours in DPI devices and their applications to device design in several emerging fields. Various modelling methods, including the most recent multi-scale approaches, are covered and the latest simulation studies of different devices are summarised and critically assessed. The potential and effectiveness of the modelling tools in optimising designs of emerging DPI devices are specifically discussed, such as those with the features of high-dose, pediatric patient compatibility and independency of patients' inhalation manoeuvres. Lastly, we summarise the challenges that remain to be addressed in DPI-related fluid and particle modelling and provide our thoughts on future research direction in this field.
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Affiliation(s)
- Zhanying Zheng
- Center for Turbulence Control, Harbin Institute of Technology, Shenzhen 518055, China
| | - Sharon Shui Yee Leung
- School of Pharmacy, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong;
| | - Raghvendra Gupta
- Department of Chemical Engineering, Indian Institute of Technology Guwahati, Assam 781039, India;
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Mitani R, Ohsaki S, Nakamura H, Watano S. Numerical Study on Particle Adhesion in Dry Powder Inhaler Device. Chem Pharm Bull (Tokyo) 2020; 68:726-736. [PMID: 32741913 DOI: 10.1248/cpb.c20-00106] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
This study investigated the particle adhesion mechanism in a capsule of dry powder inhaler (DPI) based on a combined computational fluid dynamics and discrete element method (CFD-DEM) approach. In this study, the Johnson-Kendall-Roberts (JKR) theory was selected as the adhesion force model. The simulation results corroborated the experimental results-numerous particles remained on the outlet side of the capsule, while a few particles remained on the inlet side. In the computer simulation, the modeled particles were placed in a capsule. They were quickly dispersed to both sides of the capsule, by air fed from one side of the capsule, and delivered from the air inlet side to the outlet side of the capsule. It was confirmed that vortex flows were seen at the outlet side of the capsule, which, however, were not seen at the inlet side. Numerous collisions were observed at the outlet side, while very few collisions were observed at the inlet side. These results suggested that the vortex flows were crucial to reduce the amount of residual particles in the capsule. The original capsule was then modified to enhance the vortex flow in the area, where many particles were found remaining. The modified capsule reduced the number of residual particles compared to the original capsule. This investigation suggests that the CFD-DEM approach can be a great tool for understanding the particle adhesion mechanism and improving the delivery efficiency of DPIs.
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Affiliation(s)
- Ryosuke Mitani
- Department of Chemical Engineering, Osaka Prefecture University
| | - Shuji Ohsaki
- Department of Chemical Engineering, Osaka Prefecture University
| | - Hideya Nakamura
- Department of Chemical Engineering, Osaka Prefecture University
| | - Satoru Watano
- Department of Chemical Engineering, Osaka Prefecture University
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