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Gaberino C, Rhee JS, Garcia GJM. Estimates of nasal airflow at the nasal cycle mid-point improve the correlation between objective and subjective measures of nasal patency. Respir Physiol Neurobiol 2017; 238:23-32. [PMID: 28089607 PMCID: PMC5316304 DOI: 10.1016/j.resp.2017.01.004] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2016] [Revised: 01/06/2017] [Accepted: 01/06/2017] [Indexed: 02/07/2023]
Abstract
INTRODUCTION The nasal cycle represents a significant challenge when comparing pre- and post-surgery objective measures of nasal airflow. METHODS Computational fluid dynamics (CFD) simulations of nasal airflow were conducted in 12 nasal airway obstruction patients showing significant nasal cycling between pre- and post-surgery computed tomography scans. To correct for the nasal cycle, mid-cycle models were created virtually. Subjective scores of nasal patency were obtained via the Nasal Obstruction Symptom Evaluation (NOSE) and unilateral visual analog scale (VAS). RESULTS The correlation between objective and subjective measures of nasal patency increased after correcting for the nasal cycle. In contrast to biophysical variables in individual patients, cohort averages were not significantly affected by the nasal cycle correction. CONCLUSIONS The ability to correct for the confounding effect of the nasal cycle is a key element that future virtual surgery planning software for nasal airway obstruction will need to account for when using anatomic models based on single instantaneous imaging.
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Affiliation(s)
- Courtney Gaberino
- Department of Otolaryngology and Communication Sciences, Medical College of Wisconsin, United States; Department of Biomedical Engineering, Marquette University & the Medical College of Wisconsin, United States.
| | - John S Rhee
- Department of Otolaryngology and Communication Sciences, Medical College of Wisconsin, United States.
| | - Guilherme J M Garcia
- Department of Otolaryngology and Communication Sciences, Medical College of Wisconsin, United States; Department of Biomedical Engineering, Marquette University & the Medical College of Wisconsin, United States.
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Wen J, Gu X, Wang M, Jian G, Wang S, Zheng G. The effects of injection modes on instantaneous particle deposition in a realistic human nasal cavity. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2017; 33:e02802. [PMID: 27196715 DOI: 10.1002/cnm.2802] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/12/2015] [Revised: 05/04/2016] [Accepted: 05/08/2016] [Indexed: 06/05/2023]
Abstract
To understand the instantaneous particle deposition in nasal cavity, effects of two injection models on particle deposition characteristic were discussed in this paper. Based on a realistic human nasal cavity geometry obtained from CT scans, a comparison of deposition pattern in the nasal cavity between single injection and continuous injection was investigated through the Lagrangian approach. The instantaneous airflow field was simulated with the tidal volume of 159 and 318 mL by two sine wave curves at inlet. For the case of single injection, particles have finished deposition in the first half of inhalation, and a negative correlation between the tidal volumes and deposition can be observed when the particle diameter was larger than 10 µm. Moreover, particles were mainly deposited in the turbinate area that was beneficial for aerosol therapy. The inertial parameter was not suitable to predict the particle deposition in the case of single injection. With respect to continuous injection, a reduction in total deposition caused by the deceleration process of inhalation can be observed after 1.5 s. The deposition was closely associated with the time-varying flow field, and particles were mainly deposited in the anterior region and turbinate area. Besides, the particle deposition increased with the inertial parameter for continuous injection. The results indicated that the injection modes had an influence on both the total deposition and local deposition pattern in the nasal cavity. Copyright © 2016 John Wiley & Sons, Ltd.
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Affiliation(s)
- Jian Wen
- School of Energy and Power Engineering, Xi'an Jiaotong University, 28 Xianning Rd, 710049, Xi'an, China
| | - Xin Gu
- School of Energy and Power Engineering, Xi'an Jiaotong University, 28 Xianning Rd, 710049, Xi'an, China
| | - Mengmeng Wang
- School of Chemical Engineering and Technology, Xi'an Jiaotong University, 28 Xianning Rd, 710049, Xi'an, China
| | - Guanping Jian
- School of Chemical Engineering and Technology, Xi'an Jiaotong University, 28 Xianning Rd, 710049, Xi'an, China
| | - Simin Wang
- School of Chemical Engineering and Technology, Xi'an Jiaotong University, 28 Xianning Rd, 710049, Xi'an, China
| | - Guoxi Zheng
- The Second Affiliated Hospital of Xi'an Jiaotong University (Xibei Hospital), Xi'an Jiaotong University, 28 Xianning Rd, 710049, Xi'an, China
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Rygg A, Longest PW. Absorption and Clearance of Pharmaceutical Aerosols in the Human Nose: Development of a CFD Model. J Aerosol Med Pulm Drug Deliv 2016; 29:416-431. [PMID: 26824178 PMCID: PMC8662553 DOI: 10.1089/jamp.2015.1252] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
PURPOSE The objective of this study was to develop a computational fluid dynamics (CFD) model to predict the deposition, dissolution, clearance, and absorption of pharmaceutical particles in the human nasal cavity. METHODS A three-dimensional nasal cavity geometry was converted to a surface-based model, providing an anatomically-accurate domain for the simulations. Particle deposition data from a commercial nasal spray product was mapped onto the surface model, and a mucus velocity field was calculated and validated with in vivo nasal clearance rates. A submodel for the dissolution of deposited particles was developed and validated based on comparisons to existing in vitro data for multiple pharmaceutical products. A parametric study was then performed to assess sensitivity of epithelial drug uptake to model conditions and assumptions. RESULTS The particle displacement distance (depth) in the mucus layer had a modest effect on overall drug absorption, while the mucociliary clearance rate was found to be primarily responsible for drug uptake over the timescale of nasal clearance for the corticosteroid mometasone furoate (MF). The model revealed that drug deposition in the nasal vestibule (NV) could slowly be transported into the main passage (MP) and then absorbed through connection of the liquid layer in the NV and MP regions. As a result, high intersubject variability in cumulative uptake was predicted, depending on the length of time the NV dose was left undisturbed without blowing or wiping the nose. CONCLUSIONS This study has developed, for the first time, a complete CFD model of nasal aerosol delivery from the point of spray formation through absorption at the respiratory epithelial surface. For the development and assessment of nasal aerosol products, this CFD-based in silico model provides a new option to complement existing in vitro nasal cast studies of deposition and in vivo imaging experiments of clearance.
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Affiliation(s)
- Alex Rygg
- Department of Mechanical and Nuclear Engineering, Virginia Commonwealth University, Richmond, VA
| | - P. Worth Longest
- Department of Mechanical and Nuclear Engineering, Virginia Commonwealth University, Richmond, VA
- Department of Pharmaceutics, Virginia Commonwealth University, Richmond, VA
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Effects of nasal drug delivery device and its orientation on sprayed particle deposition in a realistic human nasal cavity. Comput Biol Med 2016; 77:40-8. [DOI: 10.1016/j.compbiomed.2016.08.002] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2016] [Revised: 08/01/2016] [Accepted: 08/01/2016] [Indexed: 01/13/2023]
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Characterizing human nasal airflow physiologic variables by nasal index. Respir Physiol Neurobiol 2016; 232:66-74. [PMID: 27431449 DOI: 10.1016/j.resp.2016.07.004] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2016] [Revised: 07/13/2016] [Accepted: 07/14/2016] [Indexed: 11/21/2022]
Abstract
Although variations in nasal index (NI) have been reported to represent adaptation to climatic conditions, assessments of NI with airflow variables have not been rigorously investigated. This study uses computational fluid dynamics modeling to investigate the relationship between NI and airflow variables in 16 subjects with normal nasal anatomy. Airflow simulations were conducted under constant inspiratory pressure. Nasal resistance (NR) against NI showed weak association from nostrils to anterior inferior turbinate (R(2)=0.26) and nostril to choanae (R(2)=0.12). NI accounted for 38% and 41% of the respective variation in wall shear stress (WSS) and heat flux (HF) at the nasal vestibule, and 52% and 49% of variability in WSS and HF across the entire nose. HF and WSS had strong correlation with NI<80, and weakly correlated with NI>80; these differences in HF and WSS for NI<80 and NI>80 were not statistically significant. Results suggest strong relationship between NI and both WSS and HF but not NR, particularly in subjects with NI<80.
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Rygg A, Hindle M, Longest PW. Absorption and Clearance of Pharmaceutical Aerosols in the Human Nose: Effects of Nasal Spray Suspension Particle Size and Properties. Pharm Res 2016; 33:909-21. [PMID: 26689412 PMCID: PMC8662548 DOI: 10.1007/s11095-015-1837-5] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2015] [Accepted: 12/01/2015] [Indexed: 12/19/2022]
Abstract
PURPOSE The objective of this study was to use a recently developed nasal dissolution, absorption, and clearance (DAC) model to evaluate the extent to which suspended drug particle size influences nasal epithelial drug absorption for a spray product. METHODS Computational fluid dynamics (CFD) simulations of mucociliary clearance and drug dissolution were used to calculate total and microscale epithelial absorption of drug delivered with a nasal spray pump. Ranges of suspended particle sizes, drug solubilities, and partition coefficients were evaluated. RESULTS Considering mometasone furoate as an example, suspended drug particle sizes in the range of 1-5 μm did not affect the total nasal epithelial uptake. However, the microscale absorption of suspended drug particles with low solubilities was affected by particle size and this controlled the extent to which the drug penetrated into the distal nasal regions. CONCLUSIONS The nasal-DAC model was demonstrated to be a useful tool in determining the nasal exposure of spray formulations with different drug particle sizes and solubilities. Furthermore, the model illustrated a new strategy for topical nasal drug delivery in which drug particle size is selected to increase the region of epithelial surface exposure using mucociliary clearance while minimizing the drug dose exiting the nasopharynx.
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Affiliation(s)
- Alex Rygg
- Department of Mechanical and Nuclear Engineering, Virginia Commonwealth University, Richmond, Virginia, USA
| | - Michael Hindle
- Department of Pharmaceutics, Virginia Commonwealth University, 401 West Main Street, P.O. Box 843015, Richmond, Virginia, 23284-3015, USA
| | - P Worth Longest
- Department of Mechanical and Nuclear Engineering, Virginia Commonwealth University, Richmond, Virginia, USA.
- Department of Pharmaceutics, Virginia Commonwealth University, 401 West Main Street, P.O. Box 843015, Richmond, Virginia, 23284-3015, USA.
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Keeler JA, Patki A, Woodard CR, Frank-Ito DO. A Computational Study of Nasal Spray Deposition Pattern in Four Ethnic Groups. J Aerosol Med Pulm Drug Deliv 2016; 29:153-66. [PMID: 26270330 PMCID: PMC4855781 DOI: 10.1089/jamp.2014.1205] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2014] [Accepted: 06/15/2015] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Very little is known about the role of nasal morphology due to ethnic variation on particle deposition pattern in the sinonasal cavity. This preliminary study utilizes computational fluid dynamics (CFD) modeling to investigate sinonasal airway morphology and deposition patterns of intranasal sprayed particles in the nose and sinuses of individuals from four different ethnic groups: African American (Black); Asian; Caucasian; and Latin American. METHODS Sixteen subjects (four from each ethnic group) with "normal" sinus protocol computed tomography (CT) were selected for CFD analysis. Three-dimensional reconstruction of each subject's sinonasal cavity was created from their personal CT images. CFD simulations were carried out in ANSYS Fluent(™) in two phases: airflow phase was done by numerically solving the Navier-Stokes equations for steady state laminar inhalation; and particle dispersed phase was solved by tracking injected (sprayed) particles through the calculated airflow field. A total of 10,000 particle streams were released from each nostril, 1000 particles per diameter ranging from 5 μm to 50 μm, with size increments of 5 μm. RESULTS As reported in the literature, Caucasians (5.31 ± 0.42 cm(-1)) and Latin Americans (5.16 ± 0.40cm(-1)) had the highest surface area to volume ratio, while African Americans had highest nasal index (95.91 ± 2.22). Nasal resistance (NR) was highest among Caucasians (0.046 ± 0.008 Pa.s/mL) and Asians (0.042 ± 0.016Pa.s/mL). Asians and African Americans had the most regions with particle deposition for small (5 μm-15 μm) and large (20 μm-50 μm) particle sizes, respectively. Asians and Latin Americans individuals had the most consistent regional particle deposition pattern in the main nasal cavities within their respective ethnic groups. CONCLUSIONS Preliminary results from these ethnic groups investigated showed that Caucasians and Latin Americans had the least patent nasal cavity. Furthermore, Caucasians and African Americans had the lowest inter-subject consistency in regional particle deposition pattern; this may be due to greater inter-subject variability in their respective nasal vestibule morphology.
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Affiliation(s)
- Jarrod A Keeler
- Division of Otolaryngology, Head and Neck Surgery, Duke University Medical Center , Durham, North Carolina
| | - Aniruddha Patki
- Division of Otolaryngology, Head and Neck Surgery, Duke University Medical Center , Durham, North Carolina
| | - Charles R Woodard
- Division of Otolaryngology, Head and Neck Surgery, Duke University Medical Center , Durham, North Carolina
| | - Dennis O Frank-Ito
- Division of Otolaryngology, Head and Neck Surgery, Duke University Medical Center , Durham, North Carolina
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Frank-Ito DO, Wofford M, Schroeter JD, Kimbell JS. Influence of Mesh Density on Airflow and Particle Deposition in Sinonasal Airway Modeling. J Aerosol Med Pulm Drug Deliv 2016; 29:46-56. [PMID: 26066089 PMCID: PMC6913122 DOI: 10.1089/jamp.2014.1188] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2014] [Accepted: 03/14/2015] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND There are methodological ambiguities in the literature on mesh refinement analysis for computational fluid dynamics (CFD) modeling of physiologically realistic airflow dynamics and particle transport in the human sinonasal cavity. To investigate grid independence in discretization of the (sino)nasal geometry, researchers have considered CFD variables such as pressure drop, velocity profile, wall shear, airflow, and particle deposition fractions. Standardization in nasal geometry is also lacking: unilateral or bilateral nasal cavities with and without paranasal sinuses have been used. These methodological variants have led to inconsistencies in establishing grid-independent mesh densities. The aim of this study is to provide important insight in the role of mesh refinement analysis on airflow and particle deposition in sinonasal airway modeling. METHODS A three-dimensional reconstruction of the complete sinonasal cavity was created from computed tomography images of a subject who had functional endoscopic sinus surgery. To investigate airflow grid independence, nine different tetrahedral mesh densities were generated. For particle transport mesh refinement analysis, hybrid tetrahedral-prism elements with near-wall prisms ranging from 1 to 6 layers were implemented. Steady-state, laminar inspiratory airflow simulations under physiologic pressure-driven conditions and nebulized particle transport simulations were performed with particle sizes ranging from 1-20 μm. RESULTS Mesh independence for sinonasal airflow was achieved with approximately 4 million unstructured tetrahedral elements. The hybrid mesh containing 4 million tetrahedral cells with three prism layers demonstrated asymptotic behavior for sinonasal particle deposition. Inclusion of boundary prism layers reduced deposition fractions relative to tetrahedral-only meshes. CONCLUSIONS To ensure numerically accurate simulation results, mesh refinement analyses should be performed for both airflow and particle transport simulations. Tetrahedral-only meshes overpredict particle deposition and are less accurate than hybrid tetrahedral-prism meshes.
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Affiliation(s)
- Dennis O. Frank-Ito
- Division of Otolaryngology, Head and Neck Surgery, Duke University Medical Center, Durham, North Carolina
| | - Matthew Wofford
- Department of Otolaryngology, Head and Neck Surgery, University of North Carolina, Chapel Hill, North Carolina
| | | | - Julia S. Kimbell
- Department of Otolaryngology, Head and Neck Surgery, University of North Carolina, Chapel Hill, North Carolina
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Shang Y, Dong J, Inthavong K, Tu J. Comparative numerical modeling of inhaled micron-sized particle deposition in human and rat nasal cavities. Inhal Toxicol 2015; 27:694-705. [PMID: 26406158 DOI: 10.3109/08958378.2015.1088600] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Micron-sized particle deposition in anatomically realistic models of a rat and human nasal cavity was numerically investigated. A steady laminar inhalation flow rate was applied and particles were released from the outside air. Particles showing equivalent total particle deposition fractions were classified into low, medium and high inertial particle. Typical particle sizes are 2.5, 9 and 20 μm for the human model and 1, 2 and 3 μm for the rat model, respectively. Using a surface-mapping technique the 3D nasal cavity surface was "unwrapped" into a 2D domain and the particle deposition locations were plotted for complete visual coverage of the domain surface. The total surface area comparison showed that the surface area of the human nasal model was about ten times the size of the rat model. In contrast, the regional surface area percentage analysis revealed the olfactory region of the rat model was significantly larger than all other regions making up ∼55.6% of the total surface area, while that of the human nasal model only occupying 10.5%. Flow pattern comparisons showed rapid airflow acceleration was found at the nasopharynx region and the nostril region for the human and rat model, respectively. For the human model, the main passage is the major deposition region for micro-particles. While for the rat model, it is the vestibule. Through comparing the regional deposition flux between human and rat models, this study can contribute towards better extrapolation approach of inhalation exposure data between inter-subject species.
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Affiliation(s)
- Yidan Shang
- a School of Aerospace, Mechanical & Manufacturing Engineering, and Platform Technologies Research Institute (PTRI), RMIT University , Bundoora , VIC , Australia
| | - Jingliang Dong
- a School of Aerospace, Mechanical & Manufacturing Engineering, and Platform Technologies Research Institute (PTRI), RMIT University , Bundoora , VIC , Australia
| | - Kiao Inthavong
- a School of Aerospace, Mechanical & Manufacturing Engineering, and Platform Technologies Research Institute (PTRI), RMIT University , Bundoora , VIC , Australia
| | - Jiyuan Tu
- a School of Aerospace, Mechanical & Manufacturing Engineering, and Platform Technologies Research Institute (PTRI), RMIT University , Bundoora , VIC , Australia
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Numerical simulation of airflow and micro-particle deposition in human nasal airway pre- and post-virtual sphenoidotomy surgery. Comput Biol Med 2015; 61:8-18. [PMID: 25862997 DOI: 10.1016/j.compbiomed.2015.03.015] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2014] [Revised: 02/19/2015] [Accepted: 03/14/2015] [Indexed: 11/23/2022]
Abstract
In the present study, the effects of endoscopic sphenoidotomy surgery on the flow patterns and deposition of micro-particles in the human nasal airway and sphenoid sinus were investigated. A realistic model of a human nasal passage including nasal cavity and paranasal sinuses was constructed using a series of CT scan images of a healthy subject. Then, a virtual sphenoidotomy by endoscopic sinus surgery was performed in the left nasal passage and sphenoid sinus. Transient airflow patterns pre- and post-surgery during a full breathing cycle (inhalation and exhalation) were simulated numerically under cyclic flow condition. The Lagrangian approach was used for evaluating the transport and deposition of inhaled micro-particles. An unsteady particle tracking was performed for the inhalation phase of the breathing cycle for the case that particles were continuously entering into the nasal airway. The total deposition pattern and sphenoid deposition fraction of micro-particles were evaluated and compared for pre- and post-surgery cases. The presented results show that sphenoidotomy increased the airflow into the sphenoid sinus, which led to increased deposition of micro-particles in this region. Particles up to 25 μm were able to penetrate into the sphenoid in the post-operation case, and the highest deposition in the sphenoid for the resting breathing rate occurred for 10 μm particles at about 1.5%.
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Frank-Ito DO, Schulz K, Vess G, Witsell DL. Changes in aerodynamics during vocal cord dysfunction. Comput Biol Med 2015; 57:116-22. [DOI: 10.1016/j.compbiomed.2014.12.004] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2014] [Revised: 12/03/2014] [Accepted: 12/05/2014] [Indexed: 12/01/2022]
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Walenga RL, Tian G, Hindle M, Yelverton J, Dodson K, Longest PW. Variability in Nose-to-Lung Aerosol Delivery. JOURNAL OF AEROSOL SCIENCE 2014; 78:11-29. [PMID: 25308992 PMCID: PMC4187112 DOI: 10.1016/j.jaerosci.2014.08.003] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Nasal delivery of lung targeted pharmaceutical aerosols is ideal for drugs that need to be administered during high flow nasal cannula (HFNC) gas delivery, but based on previous studies losses and variability through both the delivery system and nasal cavity are expected to be high. The objective of this study was to assess the variability in aerosol delivery through the nose to the lungs with a nasal cannula interface for conventional and excipient enhanced growth (EEG) delivery techniques. A database of nasal cavity computed tomography (CT) scans was collected and analyzed, from which four models were selected to represent a wide range of adult anatomies, quantified based on the nasal surface area-to-volume ratio (SA/V). Computational fluid dynamics (CFD) methods were validated with existing in vitro data and used to predict aerosol delivery through a streamlined nasal cannula and the four nasal models at a steady state flow rate of 30 L/min. Aerosols considered were solid particles for EEG delivery (initial 0.9 μm and 1.5 μm aerodynamic diameters) and conventional droplets (5 μm) for a control case. Use of the EEG approach was found to reduce depositional losses in the nasal cavity by an order of magnitude and substantially reduce variability. Specifically, for aerosol deposition efficiency in the four geometries, the 95% confidence intervals (CI) for 0.9 and 5 μm aerosols were 2.3-3.1 and 15.5-66.3%, respectively. Simulations showed that the use of EEG as opposed to conventional methods improved delivered dose of aerosols through the nasopharynx, expressed as penetration fraction (PF), by approximately a factor of four. Variability of PF, expressed by the coefficient of variation (CV), was reduced by a factor of four with EEG delivery compared with the control case. Penetration fraction correlated well with SA/V for larger aerosols, but smaller aerosols showed some dependence on nasopharyngeal exit hydraulic diameter. In conclusion, results indicated that the EEG technique not only improved lung aerosol delivery, but largely eliminated variability in both nasal depositional loss and lung PF in a newly developed set of nasal airway models.
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Affiliation(s)
- Ross L Walenga
- Department of Mechanical and Nuclear Engineering, Virginia Commonwealth University, Richmond, VA
| | - Geng Tian
- Department of Mechanical and Nuclear Engineering, Virginia Commonwealth University, Richmond, VA
| | - Michael Hindle
- Department of Pharmaceutics, Virginia Commonwealth University, Richmond, VA
| | - Joshua Yelverton
- Department of Otolaryngology – Head and Neck Surgery, Virginia Commonwealth University, Richmond, VA
| | - Kelley Dodson
- Department of Otolaryngology – Head and Neck Surgery, Virginia Commonwealth University, Richmond, VA
| | - P. Worth Longest
- Department of Mechanical and Nuclear Engineering, Virginia Commonwealth University, Richmond, VA
- Department of Pharmaceutics, Virginia Commonwealth University, Richmond, VA
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Inthavong K, Fung MC, Yang W, Tu J. Measurements of droplet size distribution and analysis of nasal spray atomization from different actuation pressure. J Aerosol Med Pulm Drug Deliv 2014; 28:59-67. [PMID: 24914675 DOI: 10.1089/jamp.2013.1093] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND To evaluate the deposition efficiency of spray droplets in a nasal cavity produced from a spray device, it is important to determine droplet size distribution, velocity, and its dispersion during atomization. Due to the limiting geometric dimensions of the nasal cavity airway, the spray plume cannot develop to its full size inside the nasal vestibule to penetrate the nasal valve region for effective drug deposition. METHODS Particle/droplet image analysis was used to determine local mean droplet sizes at eight regions within the spray plume under different actuation pressures that represent typical hand operation from pediatric to adult patients. RESULTS The results showed that higher actuation pressure produces smaller droplets in the atomization. Stronger actuation pressure typical of adult users produces a longer period of the fully atomized spray stage, despite a shorter overall spray duration. This produces finer droplets when compared with the data obtained by weaker actuation pressure, typical of pediatric users. CONCLUSION The experimental technique presented is able to capture a more complete representation of the droplet size distribution and the atomization process during an actuation. The measured droplet size distribution produced can be related to the empirically defined deposition efficiency curve of the nasal cavity, allowing a prediction of the likely deposition.
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Affiliation(s)
- Kiao Inthavong
- 1 School of Aerospace, Mechanical and Manufacturing Engineering, RMIT University , Bundoora, Victoria, Australia
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Anderson KR, Anthony TR. Computational fluid dynamics investigation of human aspiration in low velocity air: orientation effects on nose-breathing simulations. THE ANNALS OF OCCUPATIONAL HYGIENE 2014; 58:625-45. [PMID: 24665111 PMCID: PMC4305117 DOI: 10.1093/annhyg/meu018] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/21/2013] [Revised: 02/13/2014] [Accepted: 02/14/2014] [Indexed: 11/14/2022]
Abstract
An understanding of how particles are inhaled into the human nose is important for developing samplers that measure biologically relevant estimates of exposure in the workplace. While previous computational mouth-breathing investigations of particle aspiration have been conducted in slow moving air, nose breathing still required exploration. Computational fluid dynamics was used to estimate nasal aspiration efficiency for an inhaling humanoid form in low velocity wind speeds (0.1-0.4 m s(-1)). Breathing was simplified as continuous inhalation through the nose. Fluid flow and particle trajectories were simulated over seven discrete orientations relative to the oncoming wind (0, 15, 30, 60, 90, 135, 180°). Sensitivities of the model simplification and methods were assessed, particularly the placement of the recessed nostril surface and the size of the nose. Simulations identified higher aspiration (13% on average) when compared to published experimental wind tunnel data. Significant differences in aspiration were identified between nose geometry, with the smaller nose aspirating an average of 8.6% more than the larger nose. Differences in fluid flow solution methods accounted for 2% average differences, on the order of methodological uncertainty. Similar trends to mouth-breathing simulations were observed including increasing aspiration efficiency with decreasing freestream velocity and decreasing aspiration with increasing rotation away from the oncoming wind. These models indicate nasal aspiration in slow moving air occurs only for particles <100 µm.
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Affiliation(s)
- Kimberly R Anderson
- Department of Environmental and Radiological Health Sciences, Colorado State University, 1681 Campus Delivery, Fort Collins, CO 80523, USA
| | - T Renée Anthony
- Department of Occupational and Environmental Health, University of Iowa, 145 N. Riverside Drive, Iowa City, IA 52242, USA
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Burgos MA, Sanmiguel-Rojas E, Martín-Alcántara A, Hidalgo-Martínez M. Effects of the ambient temperature on the airflow across a Caucasian nasal cavity. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2014; 30:430-445. [PMID: 24574201 DOI: 10.1002/cnm.2616] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/07/2013] [Revised: 10/24/2013] [Accepted: 10/27/2013] [Indexed: 06/03/2023]
Abstract
We analyse the effects of the air ambient temperature on the airflow across a Caucasian nasal cavity under different ambient temperatures using CFD simulations. A three-dimensional nasal model was constructed from high-resolution computed tomography images for a nasal cavity from a Caucasian male adult. An exhaustive parametric study was performed to analyse the laminar-compressible flow driven by two different pressure drops between the nostrils and the nasopharynx, which induced calm breathing flow rates ࣈ 5.7 L/min and ࣈ 11.3 L/min. The inlet air temperature covered the range - 10(o) C ⩽ To ⩽50(o) C. We observed that, keeping constant the wall temperature of the nasal cavity at 37(o) C, the ambient temperature affects mainly the airflow velocity into the valve region. Surprisingly, we found an excellent linear relationship between the ambient temperature and the air average temperature reached at different cross sections, independently of the pressure drop applied. Finally, we have also observed that the spatial evolution of the mean temperature data along the nasal cavity can be collapsed for all ambient temperatures analysed with the introduction of suitable dimensionless variables, and this evolution can be modelled with the help of hyperbolic functions, which are based on the heat exchanger theory.
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Affiliation(s)
- M A Burgos
- Departamento de Ingeniería Térmica y de Fluidos, Universidad Politécnica de Cartagena, Spain
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Schroeter JD, Tewksbury EW, Wong BA, Kimbell JS. Experimental measurements and computational predictions of regional particle deposition in a sectional nasal model. J Aerosol Med Pulm Drug Deliv 2014; 28:20-9. [PMID: 24580111 DOI: 10.1089/jamp.2013.1084] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Knowledge of the regional deposition of inhaled particles in the nose is important for drug delivery and assessment of the toxicity of inhaled materials. In this study, computational fluid dynamics (CFD) predictions and experimental measurements in a nasal replica cast were used to study regional deposition of inhaled microparticles. METHODS The replica cast was sectioned into six regions of interest based on nasal anatomy: the nasal vestibule, nasal valve, anterior turbinates, olfactory region, turbinates, and nasopharynx. Monodisperse fluorescein particles with aerodynamic diameters of 2.6-14.3 μm were passed through the assembled cast in the presence of steady inspiratory airflow at 15 L/min. After each experiment, the cast was disassembled and the deposited fluorescein in each region was washed out and quantified with fluorescence spectrometry. A nasal CFD model was developed from the same magnetic resonance imaging scans that were used to construct the replica cast. Steady-state inspiratory airflow and particle deposition calculations were conducted in the CFD model using Fluent(™) at flow rates producing Stokes numbers comparable to experimental conditions. RESULTS Total and regional particle deposition predictions from the CFD model were compared with experimental measurements from the replica cast. Overall, good agreement was observed between CFD predictions and experimental measurements with similar deposition trends in each region of interest. CFD predictions in central nasal regions demonstrated well-defined maximum values of 15%, 7%, and 12% in the anterior turbinates, olfactory, and turbinates regions, respectively, at particle sizes of 10-11 μm. CONCLUSIONS These results demonstrate the use of a sectioned nasal CFD model based on anatomical regions of interest for nasal drug delivery to elucidate patterns of regional deposition within a human nasal cavity.
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67
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Garcia GJM, Kimbell JS, Frank-Ito DO. In reference to Regional peak mucosal cooling predicts the perception of nasal patency. Laryngoscope 2014; 124:E210. [PMID: 24443036 DOI: 10.1002/lary.24600] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2013] [Accepted: 12/18/2013] [Indexed: 11/10/2022]
Affiliation(s)
- Guilherme J M Garcia
- Department of Otolaryngology and Communication Sciences, and Biotechnology and Bioengineering Center, Medical College of Wisconsin, Milwaukee, Wisconsin, U.S.A
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68
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High resolution visualization and analysis of nasal spray drug delivery. Pharm Res 2014; 31:1930-7. [PMID: 24549819 DOI: 10.1007/s11095-013-1294-y] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2013] [Accepted: 12/31/2013] [Indexed: 10/25/2022]
Abstract
PURPOSE Effective nasal drug delivery of new-generation systemic drugs requires efficient devices that can achieve targeted drug delivery. It has been established that droplet size, spray plume, and droplet velocity are major contributors to drug deposition. Continual effort is needed to better understand and characterise the physical mechanisms underpinning droplet formation from nasal spray devices. METHODS High speed laser photography combined with an in-house designed automated actuation system, and a highly precise traversing unit, measurements and images magnified in small field-of-view regions within the spray was performed. RESULTS The qualitative results showed a swirling liquid sheet at the near-nozzle region as the liquid is discharged before ligaments of fluid are separated off the liquid sheet. Droplets are formed and continue to deform as they travel downstream at velocities of up to 20 m/s. Increase in actuation pressure produces more rapid atomization and discharge time where finer droplets are produced. CONCLUSIONS The results suggest that device designs should consider reducing droplet inertia to penetrate the nasal valve region, but find a way to deposit in the main nasal passage and not escape through to the lungs.
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69
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Tian G, Hindle M, Longest PW. Targeted Lung Delivery of Nasally Administered Aerosols. AEROSOL SCIENCE AND TECHNOLOGY : THE JOURNAL OF THE AMERICAN ASSOCIATION FOR AEROSOL RESEARCH 2014; 48:434-449. [PMID: 24932058 PMCID: PMC4051279 DOI: 10.1080/02786826.2014.887829] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Using the nasal route to deliver pharmaceutical aerosols to the lungs has a number of advantages including co-administration during non-invasive ventilation. The objective of this study was to evaluate the growth and deposition characteristics of nasally administered aerosol throughout the conducting airways based on delivery with streamlined interfaces implementing two forms of controlled condensational growth technology. Characteristic conducting airways were considered including a nose-mouth-throat (NMT) geometry, complete upper tracheobronchial (TB) model through the third bifurcation (B3), and stochastic individual path (SIP) model to the terminal bronchioles (B15). Previously developed streamlined nasal cannula interfaces were used for the delivery of submicrometer particles using either enhanced condensational growth (ECG) or excipient enhanced growth (EEG) techniques. Computational fluid dynamics (CFD) simulations predicted aerosol transport, growth and deposition for a control (4.7 μm) and three submicrometer condensational aerosols with budesonide as a model insoluble drug. Depositional losses with condensational aerosols in the cannula and NMT were less than 5% of the initial dose, which represents an order-of-magnitude reduction compared to the control. The condensational growth techniques increased the TB dose by a factor of 1.1-2.6x, delivered at least 70% of the dose to the alveolar region, and produced final aerosol sizes ≥2.5 μm. Compared to multiple commercial orally inhaled products, the nose-to-lung delivery approach increased dose to the biologically important lower TB region by factors as large as 35x. In conclusion, nose-to-lung delivery with streamlined nasal cannulas and condensational aerosols was highly efficient and targeted deposition to the lower TB and alveolar regions.
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Affiliation(s)
- Geng Tian
- Department of Mechanical and Nuclear Engineering, Virginia Commonwealth University, Richmond, Virginia, USA
| | - Michael Hindle
- Department of Pharmaceutics, Virginia Commonwealth University, Richmond, Virginia, USA
| | - P. Worth Longest
- Department of Mechanical and Nuclear Engineering, Virginia Commonwealth University, Richmond, Virginia, USA
- Department of Pharmaceutics, Virginia Commonwealth University, Richmond, Virginia, USA
- Address correspondence to: P. Worth Longest, Virginia Commonwealth University, 401 West Main Street, P.O. Box 843015, Richmond, VA 23284-3015, USA.
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Le Guellec S, Le Pennec D, Gatier S, Leclerc L, Cabrera M, Pourchez J, Diot P, Reychler G, Pitance L, Durand M, Jamar F, Vecellio L. Validation of anatomical models to study aerosol deposition in human nasal cavities. Pharm Res 2013; 31:228-37. [PMID: 24065586 PMCID: PMC3889297 DOI: 10.1007/s11095-013-1157-6] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2013] [Accepted: 07/22/2013] [Indexed: 11/20/2022]
Abstract
Purpose Intranasal deposition of aerosols is often studied using in vitro nasal cavity models. However, the relevance of these models to predict in vivo human deposition has not been validated. This study compared in vivo nasal aerosol deposition and in vitro deposition in a human plastinated head model (NC1) and its replica constructed from CT-scan (NC2). Methods Two nebulizers (Atomisor Sonique® and Easynose®) were used to administer a 5.6 μm aerosol of 99mTc-DTPA to seven healthy volunteers and to the nasal models. Aerosol deposition was quantified by γ-scintigraphy in the nasal, upper nasal cavity and maxillary sinus (MS) regions. The distribution of aerosol deposition was determined along three nasal cavity axes (x, y and z). Results There was no significant difference regarding aerosol deposition between the volunteers and NC1. Aerosol deposition was significantly lower in NC2 than in volunteers regarding nasal region (p < 0.05) but was similar for the upper nasal cavity and MS regions. Mean aerosol distribution for NC1 came within the standard deviation (SD) of in vivo distribution, whereas that of NC2 was outside the in vivo SD for x and y axes. Conclusions In conclusion, nasal models can be used to predict aerosol deposition produced by nebulizers, but their performance depends on their design.
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Affiliation(s)
- Sandrine Le Guellec
- DTF-Aerodrug, Faculté de Médecine, Bâtiment M, 10 ter bd Tonnellé, F-37032, Tours, France
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71
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Karakosta P, Alexopoulos AH, Kiparissides C. Computational model of particle deposition in the nasal cavity under steady and dynamic flow. Comput Methods Biomech Biomed Engin 2013; 18:514-26. [PMID: 23971966 DOI: 10.1080/10255842.2013.819856] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
A computational model for flow and particle deposition in a three-dimensional representation of the human nasal cavity is developed. Simulations of steady state and dynamic airflow during inhalation are performed at flow rates of 9-60 l/min. Depositions for particles of size 0.5-20 μm are determined and compared with experimental and simulation results from the literature in terms of deposition efficiencies. The nasal model is validated by comparison with experimental and simulation results from the literature for particle deposition under steady-state flow. The distribution of deposited particles in the nasal cavity is presented in terms of an axial deposition distribution as well as a bivariate axial deposition and particle size distribution. Simulations of dynamic airflow and particle deposition during an inhalation cycle are performed for different nasal cavity outlet pressure variations and different particle injections. The total particle deposition efficiency under dynamic flow is found to depend strongly on the dynamics of airflow as well as the type of particle injection.
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Affiliation(s)
- Paraskevi Karakosta
- a Chemical Process and Energy Resources Institute, Centre for Research and Technology Hellas , 6th km Harilaou-Thermi Road, P.O. 60361, 57001 Thessaloniki , Greece
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The use of condensational growth methods for efficient drug delivery to the lungs during noninvasive ventilation high flow therapy. Pharm Res 2013; 30:2917-30. [PMID: 23801087 DOI: 10.1007/s11095-013-1123-3] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2013] [Accepted: 06/11/2013] [Indexed: 10/26/2022]
Abstract
PURPOSE The objective of this study was to evaluate the delivery of nasally administered aerosols to the lungs during noninvasive ventilation using controlled condensational growth techniques. METHODS An optimized mixer, combined with a mesh nebulizer, was used to generate submicrometer aerosol particles using drug alone (albuterol sulfate) and with mannitol or sodium chloride added as hygroscopic excipients. The deposition and growth of these particles were evaluated in an adult nose-mouth-throat (NMT) model using in vitro experimental methods and computational fluid dynamics simulations. RESULTS Significant improvement in the lung dose (3-4× increase) was observed using excipient enhanced growth (EEG) and enhanced condensational growth (ECG) delivery modes compared to control studies performed with a conventional size aerosol (~5 μm). This was due to reduced device retention and minimal deposition in the NMT airways. Increased condensational growth of the initially submicrometer particles was observed using the ECG mode and in the presence of hygroscopic excipients. CFD predictions for regional drug deposition and aerosol size increase were in good agreement with the observed experimental results. CONCLUSIONS These controlled condensational growth techniques for the delivery of submicrometer aerosols were found to be highly efficient methods for delivering nasally-administered drugs to the lungs.
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Guastella AJ, Hickie IB, McGuinness MM, Otis M, Woods EA, Disinger HM, Chan HK, Chen TF, Banati RB. Recommendations for the standardisation of oxytocin nasal administration and guidelines for its reporting in human research. Psychoneuroendocrinology 2013; 38:612-25. [PMID: 23265311 DOI: 10.1016/j.psyneuen.2012.11.019] [Citation(s) in RCA: 272] [Impact Index Per Article: 24.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/03/2012] [Revised: 11/25/2012] [Accepted: 11/26/2012] [Indexed: 12/20/2022]
Abstract
A series of studies have reported on the salubrious effects of oxytocin nasal spray on social cognition and behavior in humans, across physiology (e.g., eye gaze, heart rate variability), social cognition (e.g., attention, memory, and appraisal), and behavior (e.g., trust, generosity). Findings suggest the potential of oxytocin nasal spray as a treatment for various psychopathologies, including autism and schizophrenia. There are, however, increasing reports of variability of response to oxytocin nasal spray between experiments and individuals. In this review, we provide a summary of factors that influence transmucosal nasal drug delivery, deposition, and their impact on bioavailability. These include variations in anatomy and resultant airflow dynamic, vascularisation, status of blood vessels, mode of spray application, gallenic formulation (including presence of uptake enhancers, control release formulation), and amount and method of administration. These key variables are generally poorly described and controlled in scientific reports, in spite of their potential to alter the course of treatment outcome studies. Based on this review, it should be of no surprise that differences emerge across individuals and experiments when nasal drug delivery methods are employed. We present recommendations for researchers to use when developing and administering the spray, and guidelines for reporting on peptide nasal spray studies in humans. We hope that these recommendations assist in establishing a scientific standard that can improve the rigor and subsequent reliability of reported effects of oxytocin nasal spray in humans.
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Affiliation(s)
- Adam J Guastella
- Brain & Mind Research Institute, University of Sydney, Sydney 2006, Australia.
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74
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Frank DO, Kimbell JS, Cannon D, Pawar SS, Rhee JS. Deviated nasal septum hinders intranasal sprays: a computer simulation study. Rhinology 2013; 50:311-8. [PMID: 22888490 DOI: 10.4193/rhino12.053] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
BACKGROUND This study investigates how deviated nasal septum affects the quantity and distribution of spray particles, and examines the effects of inspiratory airflow and head position on particle transport. METHODS Deposition of spray particles was analysed using a three-dimensional computational fluid dynamics model created from a computed tomography scan of a human nose with leftward septal deviation and a right inferior turbinate hypertrophy. Five simulations were conducted using FluentTM software, with particle sizes ranging from 20-110 μm, a spray speed of 3 m/s, plume angle of 68(deg), and with steady state inspiratory airflow either present (15.7 L/min) or absent at varying head positions. RESULTS With inspiratory airflow present, posterior deposition on the obstructed side was approximately four times less than the contralateral side, regardless of head position, and was statistically significant. When airflow was absent, predicted deposition beyond the nasal valve on the left and right sides were between 16% and 69% lower and positively influenced by a dependent head position. CONCLUSION Simulations predicted that septal deviation significantly diminished drug delivery on the obstructed side. Furthermore, increased particle penetration was associated with presence of nasal airflow. Head position is an important factor in particle deposition patterns when inspiratory airflow is absent.
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Affiliation(s)
- D O Frank
- Department of Otorhinolaryngology, University of North Carolina, Chapel Hill, NC, USA.
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75
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Ge QJ, Inthavong K, Tu JY. Local deposition fractions of ultrafine particles in a human nasal-sinus cavity CFD model. Inhal Toxicol 2012; 24:492-505. [PMID: 22746399 DOI: 10.3109/08958378.2012.694494] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Ultrafine particle deposition studies in the human nasal cavity regions often omit the paranasal sinus regions. Because of the highly diffusive nature of nanoparticles, it is conjectured that deposition by diffusion may occur in the paranasal sinuses, which may affect the residual deposition fraction that leaves the nasal cavity. Two identical CFD models of a human nasal cavity, one with sinuses and one without, were reconstructed from CT-scans to determine the uptake of ultrafine particles. In general, there was little flow passing through the paranasal sinuses. However, flow patterns revealed that some streamlines reached the upper nasal cavity near the olfactory regions. These flow paths promote particle deposition in the sphenoid and ethmoid sinuses. It was found that there were some differences in the deposition fractions and patterns for 5 and 10 nm particles between the nasal-sinus and the nasal cavity models. This difference is amplified when the flow rate is decreased and at a flow rate of 4 L/min the maximum difference was 17%. It is suggested that evaluations of nanoparticle deposition should consider some deposition occurring in the paranasal sinuses especially if flow rates are of concern.
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Affiliation(s)
- Qin Jiang Ge
- School of Aerospace, Mechanical and Manufacturing Engineering, RMIT University, Vic, Australia
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Breathing Resistance and Ultrafine Particle Deposition in Nasal–Laryngeal Airways of a Newborn, an Infant, a Child, and an Adult. Ann Biomed Eng 2012; 40:2579-95. [DOI: 10.1007/s10439-012-0603-7] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2012] [Accepted: 05/22/2012] [Indexed: 12/31/2022]
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Longest PW, Holbrook LT. In silico models of aerosol delivery to the respiratory tract - development and applications. Adv Drug Deliv Rev 2012; 64:296-311. [PMID: 21640772 PMCID: PMC3258464 DOI: 10.1016/j.addr.2011.05.009] [Citation(s) in RCA: 115] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2011] [Revised: 05/12/2011] [Accepted: 05/19/2011] [Indexed: 10/18/2022]
Abstract
This review discusses the application of computational models to simulate the transport and deposition of inhaled pharmaceutical aerosols from the site of particle or droplet formation to deposition within the respiratory tract. Traditional one-dimensional (1-D) whole-lung models are discussed briefly followed by a more in-depth review of three-dimensional (3-D) computational fluid dynamics (CFD) simulations. The review of CFD models is organized into sections covering transport and deposition within the inhaler device, the extrathoracic (oral and nasal) region, conducting airways, and alveolar space. For each section, a general review of significant contributions and advancements in the area of simulating pharmaceutical aerosols is provided followed by a more in-depth application or case study that highlights the challenges, utility, and benefits of in silico models. Specific applications presented include the optimization of an existing spray inhaler, development of charge-targeted delivery, specification of conditions for optimal nasal delivery, analysis of a new condensational delivery approach, and an evaluation of targeted delivery using magnetic aerosols. The review concludes with recommendations on the need for more refined model validations, use of a concurrent experimental and CFD approach for developing aerosol delivery systems, and development of a stochastic individual path (SIP) model of aerosol transport and deposition throughout the respiratory tract.
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Affiliation(s)
- P Worth Longest
- Department of Mechanical Engineering, Virginia Commonwealth University, Richmond, United States.
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Farhadi Ghalati P, Keshavarzian E, Abouali O, Faramarzi A, Tu J, Shakibafard A. Numerical analysis of micro- and nano-particle deposition in a realistic human upper airway. Comput Biol Med 2012; 42:39-49. [DOI: 10.1016/j.compbiomed.2011.10.005] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2011] [Revised: 09/21/2011] [Accepted: 10/19/2011] [Indexed: 11/16/2022]
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