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Fleming JS. The Use of Single Photon Emission Computed Tomography in Aerosol Medicine. J Aerosol Med Pulm Drug Deliv 2023; 36:44-53. [PMID: 36594940 DOI: 10.1089/jamp.2023.29077.jsf] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Imaging of radiolabeled aerosols provides useful in vivo data on both the initial site of deposition and its subsequent transport by mucociliary clearance and epithelial permeability. Single Photon Emission Computed Tomography (SPECT) uses a gamma camera with multiple rotating heads to produce three-dimensional (3D) images of inhaled radioaerosol labeled with technetium-99m. This enables total lung deposition and its 3D regional distribution to be quantified. Aligned 3D images of lung structure allow deposition data to be related to lung anatomy. Mucociliary clearance or epithelial permeability can be assessed from a time series of SPECT aerosol images. SPECT is slightly superior to planar imaging for measuring total lung deposition. However, it is more complex to use, and for studies where total lung deposition is the endpoint, planar imaging is recommended. However, SPECT has been shown to be clearly superior to planar imaging for assessing regional distribution of aerosol and is the method of choice for this purpose. It therefore has applications in studying the influence of regional deposition on clinical effectiveness and also in validating computer models of deposition. The inability to directly radiolabel drug molecules with 99mTc is a clear disadvantage of SPECT and limits its potential use for pharmacokinetic studies. SPECT provides a wealth of data on aerosol deposition, which has been relatively underused at present. Optimal methods of analyzing and interpreting the data need to be developed. SPECT can also, in principle, provide detailed information of mucociliary clearance and has the potential to significantly improve knowledge of this process and hence clarify the role of clearance as a biomarker.
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Affiliation(s)
- John S Fleming
- Department of Medical Physics, University Hospital Southampton NHS Foundation Trust, National Institute of Health Research Biomedical Research Centre, Southampton, United Kingdom
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Marshall H, Gibson OR, Romer LM, Illidi C, Hull JH, Kippelen P. Systemic but not local rehydration restores dehydration-induced changes in pulmonary function in healthy adults. J Appl Physiol (1985) 2021; 130:517-527. [PMID: 33300853 DOI: 10.1152/japplphysiol.00311.2020] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Water transport and local (airway) hydration are critical for the normal functioning of lungs and airways. Currently, there is uncertainty regarding the effects of systemic dehydration on pulmonary function. Our aims were 1) to clarify the impact of exercise- or fluid restriction-induced dehydration on pulmonary function in healthy adults; and 2) to establish whether systemic or local rehydration can reverse dehydration-induced alterations in pulmonary function. Ten healthy participants performed four experimental trials in a randomized order (2 h exercise in the heat twice and 28 h fluid restriction twice). Pulmonary function was assessed using spirometry and whole body plethysmography in the euhydrated, dehydrated, and rehydrated states. Oral fluid consumption was used for systemic rehydration and nebulized isotonic saline inhalation for local rehydration. Both exercise and fluid restriction induced mild dehydration (2.7 ± 0.7% and 2.5 ± 0.4% body mass loss, respectively; P < 0.001) and elevated plasma osmolality (P < 0.001). Dehydration across all four trials was accompanied by a reduction in forced vital capacity (152 ± 143 mL, P < 0.01) and concomitant increases in residual volume (216 ± 177 mL, P < 0.01) and functional residual capacity (130 ± 144 mL, P < 0.01), with no statistical differences between modes of dehydration. These changes were normalized by fluid consumption but not nebulization. Our results suggest that, in healthy adults: 1) mild systemic dehydration induced by exercise or fluid restriction leads to pulmonary function impairment, primarily localized to small airways; and 2) systemic, but not local, rehydration reverses these potentially deleterious alterations.NEW & NOTEWORTHY This study demonstrates that, in healthy adults, mild systemic dehydration induced by exercise in the heat or a prolonged period of fluid restriction leads to negative alterations in pulmonary function, primarily localized to small airways. Oral rehydration, but not nebulized isotonic saline, is able to restore pulmonary function in dehydrated individuals. Our findings highlight the importance of maintaining an adequate systemic fluid balance to preserve pulmonary function.
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Affiliation(s)
- Hannah Marshall
- Centre for Human Performance, Exercise, and Rehabilitation, Brunel University London, Uxbridge, United Kingdom
| | - Oliver R Gibson
- Centre for Human Performance, Exercise, and Rehabilitation, Brunel University London, Uxbridge, United Kingdom.,Division of Sport, Health, and Exercise Sciences, College of Health, Medicine, and Life Sciences, Brunel University London, Uxbridge, United Kingdom
| | - Lee M Romer
- Centre for Human Performance, Exercise, and Rehabilitation, Brunel University London, Uxbridge, United Kingdom.,Division of Sport, Health, and Exercise Sciences, College of Health, Medicine, and Life Sciences, Brunel University London, Uxbridge, United Kingdom
| | - Camilla Illidi
- Centre for Human Performance, Exercise, and Rehabilitation, Brunel University London, Uxbridge, United Kingdom
| | - James H Hull
- Centre for Human Performance, Exercise, and Rehabilitation, Brunel University London, Uxbridge, United Kingdom.,Department of Respiratory Medicine, Royal Brompton Hospital, London, United Kingdom
| | - Pascale Kippelen
- Centre for Human Performance, Exercise, and Rehabilitation, Brunel University London, Uxbridge, United Kingdom.,Division of Sport, Health, and Exercise Sciences, College of Health, Medicine, and Life Sciences, Brunel University London, Uxbridge, United Kingdom
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das Neves J, Sverdlov Arzi R, Sosnik A. Molecular and cellular cues governing nanomaterial-mucosae interactions: from nanomedicine to nanotoxicology. Chem Soc Rev 2021; 49:5058-5100. [PMID: 32538405 DOI: 10.1039/c8cs00948a] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Mucosal tissues constitute the largest interface between the body and the surrounding environment and they regulate the access of molecules, supramolecular structures, particulate matter, and pathogens into it. All mucosae are characterized by an outer mucus layer that protects the underlying cells from physicochemical, biological and mechanical insults, a mono-layered or stratified epithelium that forms tight junctions and controls the selective transport of solutes across it and associated lymphoid tissues that play a sentinel role. Mucus is a gel-like material comprised mainly of the glycoprotein mucin and water and it displays both hydrophilic and hydrophobic domains, a net negative charge, and high porosity and pore interconnectivity, providing an efficient barrier for the absorption of therapeutic agents. To prolong the residence time, absorption and bioavailability of a broad spectrum of active compounds upon mucosal administration, mucus-penetrating and mucoadhesive particles have been designed by tuning the chemical composition, the size, the density, and the surface properties. The benefits of utilizing nanomaterials that interact intimately with mucosae by different mechanisms in the nanomedicine field have been extensively reported. To ensure the safety of these nanosystems, their compatibility is evaluated in vitro and in vivo in preclinical and clinical trials. Conversely, there is a growing concern about the toxicity of nanomaterials dispersed in air and water effluents that unintentionally come into contact with the airways and the gastrointestinal tract. Thus, deep understanding of the key nanomaterial properties that govern the interplay with mucus and tissues is crucial for the rational design of more efficient drug delivery nanosystems (nanomedicine) and to anticipate the fate and side-effects of nanoparticulate matter upon acute or chronic exposure (nanotoxicology). This review initially overviews the complex structural features of mucosal tissues, including the structure of mucus, the epithelial barrier, the mucosal-associated lymphatic tissues and microbiota. Then, the most relevant investigations attempting to identify and validate the key particle features that govern nanomaterial-mucosa interactions and that are relevant in both nanomedicine and nanotoxicology are discussed in a holistic manner. Finally, the most popular experimental techniques and the incipient use of mathematical and computational models to characterize these interactions are described.
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Affiliation(s)
- José das Neves
- i3S - Instituto de Investigação e Inovação em Saúde & INEB - Instituto de Engenharia Biomédica, Universidade do Porto, Porto, Portugal
| | - Roni Sverdlov Arzi
- Laboratory of Pharmaceutical Nanomaterials Science, Department of Materials Science and Engineering, Technion-Israel Institute of Technology, De-Jur Building, Office 607, Haifa, 3200003, Israel.
| | - Alejandro Sosnik
- Laboratory of Pharmaceutical Nanomaterials Science, Department of Materials Science and Engineering, Technion-Israel Institute of Technology, De-Jur Building, Office 607, Haifa, 3200003, Israel.
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Gulhane A, Chen DL. Imaging in Asthma. Mol Imaging 2021. [DOI: 10.1016/b978-0-12-816386-3.00081-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
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Dentice RL, Elkins MR, Verschuer J, Eberl S, Dwyer G, Bye PTP. Side lying during nebulisation can significantly improve apical deposition in healthy adults and adults with mild cystic fibrosis lung disease: a randomised crossover trial. BMC Pulm Med 2019; 19:128. [PMID: 31311524 PMCID: PMC6636004 DOI: 10.1186/s12890-019-0886-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2019] [Accepted: 06/25/2019] [Indexed: 11/17/2022] Open
Abstract
Background In people with and without Cystic Fibrosis (CF), does side lying during nebulisation change: the proportion of the dose loaded in the nebuliser that is deposited in the lungs; the uniformity of deposition throughout the lungs; or the apical drug density as a percentage of the drug density in the remaining lung? Do these effects differ depending on the degree of lung disease present? Methods A randomised crossover trial with concealed allocation, intention-to-treat analysis and blinded assessors, involving 39 adults: 13 healthy, 13 with mild CF lung disease (FEV1 > 80%pred), and 13 with more advanced CF lung disease (FEV1 < 80%pred). In random order, 4 mL of nebulised radioaerosol was inhaled in upright sitting and in alternate right and left side lying at 2-min intervals, for 20 min. Results Compared to sitting upright, lung deposition and the uniformity of deposition were not significantly altered by side lying in any of the three groups. In sitting, the density of the deposition was significantly less in the apical regions than in the rest of the lung in all participants. Side lying significantly improved apical deposition in healthy adults (MD, 13%; 95% CI, 7 to 19), and in minimal CF lung disease (MD, 4%; 95% CI, 1 to 7) but not in advanced disease (MD, 4%; 95% CI, − 2 to 9). Conclusion Alternating between right and left side lying during nebulisation significantly improves apical deposition in healthy adults and in adults with mild CF lung disease, without substantial detriment to overall deposition. Trial registration ACTRN12611000674932 (Healthy), ACTRN12611000672954 (CF) Retrospectively registered 4/7/2011. Electronic supplementary material The online version of this article (10.1186/s12890-019-0886-7) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Ruth L Dentice
- Physiotherapy Department, Royal Prince Alfred Hospital, Sydney, Australia.
| | - Mark R Elkins
- Centre for Education & Workforce Development, Sydney Local Health District, Sydney, Australia.,Sydney Medical School, University of Sydney, Sydney, Australia
| | - Jordan Verschuer
- Department of Molecular Imaging, Royal Prince Alfred Hospital, Sydney, Australia
| | - Stefan Eberl
- Department of Molecular Imaging, Royal Prince Alfred Hospital, Sydney, Australia
| | - Genevieve Dwyer
- Physiotherapy Program, Western Sydney University, Sydney, Australia.
| | - Peter T P Bye
- Sydney Medical School, University of Sydney, Sydney, Australia.,Department of Respiratory Medicine, Royal Prince Alfred Hospital, Sydney, Australia
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Abstract
Environmental and occupational exposure to particulate aerosols is known to have negative health effects. However little is known about how these aerosols trigger the development of pathophysiological mechanisms in the body or the fate of ultrafine particles in the lungs after inhalation. The development of aerosols of different origin that can be labeled to a large variety with radionuclides compatible with clinical gamma camera systems opens the possibility of using lung scintigraphy imaging to study these causalities in detail. Lung scintigraphy (planar or SPECT) allows regional mapping of the deposition of the aerosol in the lungs and the dynamic assessment of particle clearance and translocation from the healthy and affected human lungs. In this paper, we will review the unique features of lung scintigraphy applied to aerosol clearance studies in humans.
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Affiliation(s)
- Alejandro Sanchez-Crespo
- Department of Medical Radiation Physics and Nuclear Medicine, Karolinska University Hospital, Stockholm, Sweden; Department of Oncology-pathology. Karolinska Institutet, Stockholm, Sweden.
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Preclinical evaluation of aerosol administration systems using Positron Emission Tomography. Eur J Pharm Biopharm 2018; 130:59-65. [DOI: 10.1016/j.ejpb.2018.05.037] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2018] [Revised: 05/28/2018] [Accepted: 05/31/2018] [Indexed: 11/16/2022]
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Lizal F, Jedelsky J, Morgan K, Bauer K, Llop J, Cossio U, Kassinos S, Verbanck S, Ruiz-Cabello J, Santos A, Koch E, Schnabel C. Experimental methods for flow and aerosol measurements in human airways and their replicas. Eur J Pharm Sci 2018; 113:95-131. [DOI: 10.1016/j.ejps.2017.08.021] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2017] [Revised: 08/14/2017] [Accepted: 08/17/2017] [Indexed: 12/29/2022]
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Yang MY, Verschuer J, Shi Y, Song Y, Katsifis A, Eberl S, Wong K, Brannan JD, Cai W, Finlay WH, Chan HK. The effect of device resistance and inhalation flow rate on the lung deposition of orally inhaled mannitol dry powder. Int J Pharm 2016; 513:294-301. [DOI: 10.1016/j.ijpharm.2016.09.047] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2016] [Revised: 09/12/2016] [Accepted: 09/13/2016] [Indexed: 10/21/2022]
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Ilic V, Dunet V, Le Pape A, Buchs M, Kosinski M, Bischof Delaloye A, Gerber S, Prior JO. SPECT/CT study of bronchial deposition of inhaled particles. A human aerosol vaccination model against HPV. Nuklearmedizin 2016; 55:203-8. [PMID: 27440125 DOI: 10.3413/nukmed-0811-16-03] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2016] [Accepted: 06/28/2016] [Indexed: 02/01/2023]
Abstract
AIMS Vaccination by aerosol inhalation can be used to efficiently deliver antigen against HPV to mucosal tissue, which is particularly useful in developing countries (simplicity of administration, costs, no need for cold chain). For optimal immunological response, vaccine particles should preferentially be delivered to proximal bronchial airways. We aimed at quantifying the deposition of inhaled particles in central airways and peripheral lung, and to assess administration biosafety. Participants, methods: 20 healthy volunteers (13W/7M, aged 24±4y) performed a 10-min free-breathing inhalation of (99m)Tc-stannous chloride colloid aerosol (450 MBq) in a buffer solution without vaccinal particles using an ultrasonic nebulizer (mass median aerodynamic diameter 4.2 μm) and a double mask inside a biosafety cabinet dedicated to assess environmental particle release. SPECT/CT and whole-body planar scintigraphy were acquired to determine whole-body and regional C/P distribution ratio (central-to-peripheral pulmonary deposition counts). Using a phantom, SPECT sensitivity was calibrated to obtain absolute pulmonary activity deposited by inhalation. RESULTS All participants successfully performed the inhalation that was well tolerated (no change in pulmonary peak expiratory flow rate, p = 0.9). It was environmentally safe (no activity released in the biosafety filter.) 1.3±0.6% (range 0.4-2.6%) of the total nebulizer activity was deposited in the lungs with a C/P distribution ratio of 0.40±0.20 (range 0.15-1.14). CONCLUSION Quantification and regional distribution of inhaled particles in an aerosolized vaccine model is possible using radioactive particles. This will allow optimizing deposition parameters and determining the particles charge for active-particles vaccination.
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Affiliation(s)
| | | | | | | | | | | | | | - John O Prior
- Prof. John O. Prior, PhD MD, Department of Nuclear Medicine and Molecular Imaging, Lausanne University Hospital, Rue du Bugnon 46, 1011 Lausanne, Switzerland, Tel. +41/21/314 43-48, Fax -49,
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Wang H, Sebrié C, Ruaud J, Guillot G, Bouazizi K, Willoquet G, Maître X, Darrasse L, de Rochefort L. Aerosol deposition in the lungs of spontaneously breathing rats using Gd‐DOTA‐based contrast agents and ultra‐short echo time MRI at 1.5 Tesla. Magn Reson Med 2015; 75:594-605. [DOI: 10.1002/mrm.25617] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2014] [Revised: 11/22/2014] [Accepted: 12/16/2014] [Indexed: 01/05/2023]
Affiliation(s)
- Hongchen Wang
- Imagerie par Résonance Magnétique Médicale et Multi‐Modalités (UMR8081)IR4M, Univ. Paris‐Sud, CNRSOrsay France
| | - Catherine Sebrié
- Imagerie par Résonance Magnétique Médicale et Multi‐Modalités (UMR8081)IR4M, Univ. Paris‐Sud, CNRSOrsay France
| | - Jean‐Pierre Ruaud
- Imagerie par Résonance Magnétique Médicale et Multi‐Modalités (UMR8081)IR4M, Univ. Paris‐Sud, CNRSOrsay France
| | - Geneviève Guillot
- Imagerie par Résonance Magnétique Médicale et Multi‐Modalités (UMR8081)IR4M, Univ. Paris‐Sud, CNRSOrsay France
| | - Khaoula Bouazizi
- Imagerie par Résonance Magnétique Médicale et Multi‐Modalités (UMR8081)IR4M, Univ. Paris‐Sud, CNRSOrsay France
| | - Georges Willoquet
- Imagerie par Résonance Magnétique Médicale et Multi‐Modalités (UMR8081)IR4M, Univ. Paris‐Sud, CNRSOrsay France
| | - Xavier Maître
- Imagerie par Résonance Magnétique Médicale et Multi‐Modalités (UMR8081)IR4M, Univ. Paris‐Sud, CNRSOrsay France
| | - Luc Darrasse
- Imagerie par Résonance Magnétique Médicale et Multi‐Modalités (UMR8081)IR4M, Univ. Paris‐Sud, CNRSOrsay France
| | - Ludovic de Rochefort
- Imagerie par Résonance Magnétique Médicale et Multi‐Modalités (UMR8081)IR4M, Univ. Paris‐Sud, CNRSOrsay France
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Pulmonary drug delivery by powder aerosols. J Control Release 2014; 193:228-40. [DOI: 10.1016/j.jconrel.2014.04.055] [Citation(s) in RCA: 128] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2014] [Revised: 04/27/2014] [Accepted: 04/29/2014] [Indexed: 12/24/2022]
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Leclerc L, Pourchez J, Prevot N, Vecellio L, Le Guellec S, Cottier M, Durand M. Assessing sinus aerosol deposition: benefits of SPECT-CT imaging. Int J Pharm 2013; 462:135-41. [PMID: 24374606 DOI: 10.1016/j.ijpharm.2013.12.032] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2013] [Revised: 12/12/2013] [Accepted: 12/17/2013] [Indexed: 11/30/2022]
Abstract
PURPOSE Aerosol inhalation therapy is one of the methods to treat rhinosinusitis. However the topical drug delivery to the posterior nose and paranasal sinuses shows only limited efficiency. A precise sinusal targeting remains a main challenge for aerosol treatment of sinus disorders. This paper proposes a comparative study of the nasal deposition patterns of micron and submicron particles using planar gamma-scintigraphy imaging vs. a new 3-dimensional (3D) imaging approach based on SPECT-CT measurements. METHODS Radiolabelled nebulizations have been performed on a plastinated model of human nasal cast coupled with a respiratory pump. First, the benefits provided by SPECT-CT imaging were compared with 2D gamma-scintigraphy and radioactive quantification of maxillary sinus lavage as reference for the sonic 2.8 μm aerosol sinusal deposition. Then, the impact on nasal deposition of various airborne particle sizes was assessed. RESULTS The 2D methodology overestimates aerosol deposition in the maxillary sinuses by a factor 9 whereas the 3D methodology is in agreement with the maxillary sinus lavage reference methodology. Then with the SPECT-CT approach we highlighted that the higher particle size was mainly deposited in the central nasal cavity contrary to the submicron aerosol particles (33.8 ± 0.6% of total deposition for the 2.8 μm particles vs. 1 ± 0.3% for the 230 nm particles). CONCLUSION Benefits of SPECT/CT for the assessment of radiolabelled aerosol deposition in rhinology are clearly demonstrated. This 3D methodology should be preferentially used for scintigraphic imaging of sinusal deposition in Human.
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Affiliation(s)
- Lara Leclerc
- Université Jean Monnet, LINA EA 4624, Université de Lyon, F-42023 Saint-Etienne, France; Ecole Nationale Supérieure des Mines, CIS-EMSE, LINA EA 4624, F-42023 Saint-Etienne, France; SFR IFRESIS, F-42023 Saint-Etienne, France.
| | - Jérémie Pourchez
- Ecole Nationale Supérieure des Mines, CIS-EMSE, LINA EA 4624, F-42023 Saint-Etienne, France; SFR IFRESIS, F-42023 Saint-Etienne, France
| | - Nathalie Prevot
- Université Jean Monnet, LINA EA 4624, Université de Lyon, F-42023 Saint-Etienne, France; SFR IFRESIS, F-42023 Saint-Etienne, France; CHU de Saint-Etienne, Nuclear Medicine Department, F-42055 Saint-Etienne, France
| | - Laurent Vecellio
- Centre d'Etudes des Pathologies Respiratoires INSERM U1100/EA 6305, Faculté de Médecine, Université François Rabelais, Tours, France; DTF Aerodrug, Faculté de Médecine, Université François Rabelais, Tours, France
| | - Sandrine Le Guellec
- Centre d'Etudes des Pathologies Respiratoires INSERM U1100/EA 6305, Faculté de Médecine, Université François Rabelais, Tours, France; DTF Aerodrug, Faculté de Médecine, Université François Rabelais, Tours, France
| | - Michèle Cottier
- Université Jean Monnet, LINA EA 4624, Université de Lyon, F-42023 Saint-Etienne, France; SFR IFRESIS, F-42023 Saint-Etienne, France
| | - Marc Durand
- Université Jean Monnet, LINA EA 4624, Université de Lyon, F-42023 Saint-Etienne, France; SFR IFRESIS, F-42023 Saint-Etienne, France; Centre Hospitalier Emile Roux, ENT Department, F-43012 Le Puy en Velay, France
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Abstract
Interest in bioequivalence (BE) of inhaled drugs derives largely from the desire to offer generic substitutes to successful drug products. The complexity of aerosol dosage forms renders them difficult to mimic and raises questions regarding definitions of similarities and those properties that must be controlled to guarantee both the quality and the efficacy of the product. Despite a high level of enthusiasm to identify and control desirable properties there is no clear guidance, regulatory or scientific, for the variety of aerosol dosage forms, on practical measures of BE from which products can be developed. As more data on the pharmaceutical and clinical relevance of various techniques, as described in this review, become available, it is likely that a path to the demonstration of BE will become evident. In the meantime, debate on this topic will continue.
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Fleming J, Bailey DL, Chan HK, Conway J, Kuehl PJ, Laube BL, Newman S. Standardization of Techniques for Using Single-Photon Emission Computed Tomography (SPECT) for Aerosol Deposition Assessment of Orally Inhaled Products. J Aerosol Med Pulm Drug Deliv 2012; 25 Suppl 1:S29-51. [DOI: 10.1089/jamp.2012.1su5] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- John Fleming
- Respiratory Biomedical Research Unit, University Hospital Southampton, NHS Foundation Trust, Southampton, United Kingdom
| | | | - Hak-Kim Chan
- Advanced Drug Delivery Group, The University of Sydney, New South Wales, Australia
| | - Joy Conway
- Respiratory Biomedical Research Unit, University Hospital Southampton, NHS Foundation Trust, Southampton, United Kingdom
- School of Health Sciences, University of Southampton, Southampton, United Kingdom
| | - Philip J. Kuehl
- Lovelace Respiratory Research Institute, Albuquerque, New Mexico
| | - Beth L. Laube
- Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Stephen Newman
- Scientific Consultant, Hunstanton, Norfolk, United Kingdom
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Conway J. Lung imaging - two dimensional gamma scintigraphy, SPECT, CT and PET. Adv Drug Deliv Rev 2012; 64:357-68. [PMID: 22310158 DOI: 10.1016/j.addr.2012.01.013] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2011] [Revised: 01/18/2012] [Accepted: 01/24/2012] [Indexed: 12/17/2022]
Abstract
This review will cover the principles of imaging the deposition of inhaled drugs and some of the state-of-the art imaging techniques being used today. Aerosol deposition can be imaged and quantified by the addition of a radiolabel to the aerosol formulation. The subsequent imaging of the inhaled deposition pattern can be acquired by different imaging techniques. Specifically, this review will focus on the use of two-dimensional planar, gamma scintigraphy, SPECT, CT and PET. This review will look at how these imaging techniques are used to investigate the mechanisms of drug delivery in the lung and how the lung anatomy and physiology have the potential to alter therapeutic outcomes.
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Affiliation(s)
- Joy Conway
- Faculty of Health Sciences, University of Southampton, Southampton General Hospital, UK.
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17
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King GG. Current and emerging imaging in relation to drug discovery in airways disease. Pulm Pharmacol Ther 2011; 24:497-504. [DOI: 10.1016/j.pupt.2011.07.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/22/2011] [Revised: 07/18/2011] [Accepted: 07/20/2011] [Indexed: 11/16/2022]
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Newman S, Fleming J. Challenges in assessing regional distribution of inhaled drug in the human lungs. Expert Opin Drug Deliv 2011; 8:841-55. [PMID: 21554149 DOI: 10.1517/17425247.2011.577063] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
INTRODUCTION Both the total amount of drug deposited in the lungs (whole lung deposition) and the amount deposited in different lung regions (regional lung deposition) are potentially important factors that determine the safety and efficacy of inhaled drugs. Radionuclide imaging is well established for quantifying the whole lung deposition of inhaled drugs, but the assessment of regional lung deposition is less straightforward, because of the complex nature of the lung anatomy. AREAS COVERED This review describes the challenges and problems associated with quantifying regional lung deposition by the two-dimensional (2D) radionuclide imaging method of gamma scintigraphy, and by the three-dimensional (3D) radionuclide imaging methods of single-photon-emission computed tomography (SPECT) and positron-emission tomography (PET). The advantages and disadvantages of each method for assessing regional lung deposition are discussed. EXPERT OPINION Owing to its 2D nature, gamma scintigraphy provides limited information about regional lung deposition. SPECT provides regional lung deposition data in three dimensions, but usually involves a (99m)Tc radiolabel. PET enables the regional lung deposition of radiolabeled drug molecules to be quantified in three dimensions, but poses the greatest logistical and technical difficulties. Despite their more challenging nature, 3D imaging methods should be considered as an alternative to gamma scintigraphy whenever the determination of regional lung deposition of pharmaceutical aerosols is a major study objective.
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Bennett WD, Daviskas E, Hasani A, Mortensen J, Fleming J, Scheuch G. Mucociliary and cough clearance as a biomarker for therapeutic development. J Aerosol Med Pulm Drug Deliv 2011; 23:261-72. [PMID: 20804426 DOI: 10.1089/jamp.2010.0823] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
A workshop/symposium on “Mucociliary and Cough Clearance (MCC/CC) as a Biomarker for Therapeutic Development” was held on October 21–22, 2008, in Research Triangle Park, NC, to discuss the methods for measurement of MCC/CC and how they may be optimized for assessing new therapies designed to improve clearance of airway secretions from the lungs. The utility of MCC/CC as a biomarker for disease progression and therapeutic intervention is gaining increased recognition as a valuable tool in the clinical research community. A number of investigators currently active in using MCC/CC for diagnostic or therapeutic evaluation presented details of their methodologies. Attendees participating in the workshop discussions included those interested in the physiology of MCC/CC, some of who use in vitro or animal methods for its study, pharmaceutical companies developing muco-active therapies, and many who were interested in establishing the methods in their own clinical laboratory. This review article summarizes the presentations for the in vivo human MCC/CC methods and the discussions both at and subsequent to the workshop between the authors to move forward on a number of questions raised at the workshop.
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Affiliation(s)
- William D Bennett
- Center for Environmental Medicine, Asthma and Lung Biology, University of North Carolina–Chapel Hill, Chapel Hill, North Carolina 27599-7310, USA.
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Forbes B, Asgharian B, Dailey LA, Ferguson D, Gerde P, Gumbleton M, Gustavsson L, Hardy C, Hassall D, Jones R, Lock R, Maas J, McGovern T, Pitcairn GR, Somers G, Wolff RK. Challenges in inhaled product development and opportunities for open innovation. Adv Drug Deliv Rev 2011; 63:69-87. [PMID: 21144875 DOI: 10.1016/j.addr.2010.11.004] [Citation(s) in RCA: 90] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2010] [Revised: 11/19/2010] [Accepted: 11/25/2010] [Indexed: 11/26/2022]
Abstract
Dosimetry, safety and the efficacy of drugs in the lungs are critical factors in the development of inhaled medicines. This article considers the challenges in each of these areas with reference to current industry practices for developing inhaled products, and suggests collaborative scientific approaches to address these challenges. The portfolio of molecules requiring delivery by inhalation has expanded rapidly to include novel drugs for lung disease, combination therapies, biopharmaceuticals and candidates for systemic delivery via the lung. For these drugs to be developed as inhaled medicines, a better understanding of their fate in the lungs and how this might be modified is required. Harmonized approaches based on 'best practice' are advocated for dosimetry and safety studies; this would provide coherent data to help product developers and regulatory agencies differentiate new inhaled drug products. To date, there are limited reports describing full temporal relationships between pharmacokinetic (PK) and pharmacodynamic (PD) measurements. A better understanding of pulmonary PK and PK/PD relationships would help mitigate the risk of not engaging successfully or persistently with the drug target as well as identifying the potential for drug accumulation in the lung or excessive systemic exposure. Recommendations are made for (i) better industry-academia-regulatory co-operation, (ii) sharing of pre-competitive data, and (iii) open innovation through collaborative research in key topics such as lung deposition, drug solubility and dissolution in lung fluid, adaptive responses in safety studies, biomarker development and validation, the role of transporters in pulmonary drug disposition, target localisation within the lung and the determinants of local efficacy following inhaled drug administration.
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Iida H, Nakagawara J, Hayashida K, Fukushima K, Watabe H, Koshino K, Zeniya T, Eberl S. Multicenter evaluation of a standardized protocol for rest and acetazolamide cerebral blood flow assessment using a quantitative SPECT reconstruction program and split-dose 123I-iodoamphetamine. J Nucl Med 2010; 51:1624-31. [PMID: 20847163 DOI: 10.2967/jnumed.110.078352] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
UNLABELLED SPECT can provide valuable diagnostic and treatment response information in large-scale multicenter clinical trials. However, SPECT has been limited in providing consistent quantitative functional parametric values across the centers, largely because of a lack of standardized procedures to correct for attenuation and scatter. Recently, a novel software package has been developed to reconstruct quantitative SPECT images and assess cerebral blood flow (CBF) at rest and after acetazolamide challenge from a single SPECT session. This study was aimed at validating this technique at different institutions with a variety of SPECT devices and imaging protocols. METHODS Twelve participating institutions obtained a series of SPECT scans on physical phantoms and clinical patients. The phantom experiments included the assessment of septal penetration for each collimator used and of the accuracy of the reconstructed images. Clinical studies were divided into 3 protocols, including intrainstitutional reproducibility, a comparison with PET, and rest-rest study consistency. The results from 46 successful studies were analyzed. RESULTS Activity concentration estimation (Bq/mL) in the reconstructed SPECT images of a uniform cylindric phantom showed an interinstitution variation of ±5.1%, with a systematic underestimation of concentration by 12.5%. CBF values were reproducible both at rest and after acetazolamide on the basis of repeated studies in the same patient (mean ± SD difference, -0.4 ± 5.2 mL/min/100 g, n = 44). CBF values were also consistent with those determined using PET (-6.1 ± 5.1 mL/min/100 g, n = 6). CONCLUSION This study demonstrates that SPECT can quantitatively provide physiologic functional images of rest and acetazolamide challenge CBF, using a quantitative reconstruction software package.
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Affiliation(s)
- Hidehiro Iida
- Dual-Table Autoradiography SPECT Research Group in Japan, Osaka, Japan.
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Glover W, Chan HK, Eberl S, Daviskas E, Anderson S. Lung Deposition of Mannitol Powder Aerosol in Healthy Subjects. ACTA ACUST UNITED AC 2006; 19:522-32. [PMID: 17196080 DOI: 10.1089/jam.2006.19.522] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Mannitol as a dry powder aerosol is used for bronchoprovocation testing and to enhance mucus clearance in people with excessive airway secretions. The dose and distribution of the deposited aerosol in the lung was investigated using fast single photon emission tomography (SPECT) imaging. Mannitol powder (3 microm particle size) was produced by spray drying and radiolabeled with (99m)Tc-DTPA. Approximately 60 mg of radiolabeled mannitol (containing 52-68 MBq of (99m)Tc-DTPA) was administered to 10 healthy subjects using the Inhalator dry powder inhaler (DPI), and SPECT images (1 min each) were collected. Thirteen percent to 31% of the dose of mannitol loaded in the inhaler deposited in the lungs and the deposited dose correlated positively with the peak inhalation air flow. The regional aerosol lung distribution, as expressed by the penetration index (i.e., ratio of peripheral to central deposition in the lung) varied from 0.31 to 0.88, which however showed no dependency on any flow parameters. The variation in response to the same dose of mannitol within the asthmatic population may in part be explained by these findings.
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Affiliation(s)
- William Glover
- Faculty of Pharmacy, University of Sydney, Sydney, Australia
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Zhang Z, Kleinstreuer C, Kim CS. Isotonic and hypertonic saline droplet deposition in a human upper airway model. ACTA ACUST UNITED AC 2006; 19:184-98. [PMID: 16796543 DOI: 10.1089/jam.2006.19.184] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The evaporative and hygroscopic effects and deposition of isotonic and hypertonic saline droplets have been simulated from the mouth to the first four generations of the tracheobronchial tree under laminar-transitional-turbulent inspiratory flow conditions. Specifically, the local water vapor transport, droplet evaporation rate, and deposition fractions are analyzed. The effects of inhalation flow rates, thermodynamic air properties and NaCl-droplet concentrations of interest are discussed as well. The validated computer simulation results indicate that the increase of NaCl-solute concentration, increase of inlet relative humidity, or decrease of inlet air temperature may reduce water evaporation and increase water condensation at saline droplet surfaces, resulting in higher droplet depositions due to the increasing particle diameter and density. However, solute concentrations below 10% may not have a very pronounced effect on droplet deposition in the human upper airways.
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Affiliation(s)
- Zhe Zhang
- Department of Mechanical and Aerospace Engineering, North Carolina State University, Raleigh, North Carolina 27695-7910, USA
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Eberl S, Chan HK, Daviskas E. SPECT Imaging for Radioaerosol Deposition and Clearance Studies. ACTA ACUST UNITED AC 2006; 19:8-20. [PMID: 16551210 DOI: 10.1089/jam.2006.19.8] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Planar gamma camera scintigraphy is well established for measuring the deposition and clearance of radioaerosols. Single photon emission computed tomography (SPECT) provides threedimensional (3D) reconstructions of the radioactivity distribution, thus avoiding the compression of 3D data into two-dimensional (2D) images and potentially offering superior assessment of aerosol deposition patterns. However, SPECT has traditionally been associated with long imaging times, making it unsuitable for measuring deposition and clearance of radioaerosols with fast clearance. Multi-detector SPECT systems can collect complete SPECT studies in <1 min, allowing both initial deposition and clearance over time to be assessed by dynamic SPECT. Simultaneous transmission measurement with an external source provides attenuation correction for absolute activity quantification as well as aiding in the definition of the lung volume of interest. A dynamic SPECT imaging protocol has been developed to allow fast imaging from the oropharynx to the abdomen using gamma cameras with limited axial field of views. This allows activity quantification not only in the lungs, but also in areas outside the thorax. However, fast dynamic SPECT imaging is technically and computationally more demanding and provides less scope for reducing the radioactivity administered to the subjects. It has been shown that dynamic SPECT, compared to planar imaging, is more sensitive in detecting changes in deposition as measured by the Penetration Index (PI). Thus, SPECT can better differentiate between large and small airways, which is important for lung regional analysis.
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Affiliation(s)
- Stefan Eberl
- Department of PET and Nuclear Medicine, Royal Prince Alfred Hospital, Sydney, NSW, Australia.
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Abstract
Imaging has traditionally been separated into two distinct disciplines: functional imaging and structural imaging. Functional imaging encompasses applications such as nuclear medicine (single photon emission computed tomography [SPECT] and positron emission tomography [PET]), autoradiography, magnetic resonance spectroscopy (MRS) and magneto-encephalography (MEG), while structural, or anatomical, imaging includes planar radiography, x-ray computed tomography (CT), and magnetic resonance imaging (MRI). However, today, the distinctions between these are blurring due to advances in software fusion and the development of multi-modality (SPECT/CT, PET/CT) scanners. New techniques such as MRI using hyperpolarized gases (3H and 129Xe) and xenon K-edge synchrotron x-ray subtraction imaging are also being developed to provide the researcher with a variety of ways to probe the airways, and the distribution of pharmaceuticals and subsequent uptake and bio-distribution. This paper reviews advances in imaging to present a contemporary view of the tools available.
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Affiliation(s)
- Dale L Bailey
- Department of Nuclear Medicine, Royal North Shore Hospital, Sydney, Australia.
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Chan HK, Chiou H, Kwok P. The 15th International Society of Aerosols in Medicine Congress. Perth, Australia, 14-18 March 2005. Expert Opin Drug Deliv 2005; 3:163-7. [PMID: 16370947 DOI: 10.1517/17425247.3.1.163] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
This international meeting brought together approximately 250 delegates from the pharmaceutical industry, academia, hospitals and government agencies, to discuss the latest research and development on areas related to inhalation aerosols. Fundamental science and applied research encompassing both the biological and physicochemical aspects were presented. There was a wide range of topics covered, from immune modulation to pharmaceutical regulatory issues, including aerosol clearance; industry innovations; aerosols and in utero effects; technical advances in imaging; inhalation catastrophes; as well as recent advances and future directions in aerosol delivery systems. This biennial congress has provided an excellent forum for stimulating fruitful discussion of aerosols in medicine.
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Affiliation(s)
- Hak-Kim Chan
- Faculty of Pharmacy, University of Sydney, NSW 2006, Australia.
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Newman SP, Pitcairn GR, Hirst PH, Rankin L. Radionuclide imaging technologies and their use in evaluating asthma drug deposition in the lungs. Adv Drug Deliv Rev 2003; 55:851-67. [PMID: 12842604 DOI: 10.1016/s0169-409x(03)00081-4] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Whole lung and regional lung deposition of inhaled asthma drugs in the lungs can be quantified using either two-dimensional or three-dimensional radionuclide imaging methods. The two-dimensional method of gamma scintigraphy has been the most widely used, and is currently considered the industry standard, but the three-dimensional methods (SPECT, single photon emission computed tomography; and PET, positron emission tomography) give superior regional lung deposition data and will undoubtedly be used more frequently in future. Recent developments in radionuclide imaging are described, including an improved algorithm for assessing regional lung deposition in gamma scintigraphy, and a patent-protected radiolabelling method (TechneCoat), applicable to both gamma scintigraphy and SPECT. Radionuclide imaging data on new inhaled asthma products provide a milestone assessment, and the data form a bridge between in vitro testing and a full clinical trials program, allowing the latter to be entered with increased confidence.
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Affiliation(s)
- Stephen P Newman
- Pharmaceutical Profiles Ltd, Mere Way, Ruddington Fields, Ruddington, Nottingham NG11 6JS, UK.
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Chan HK, Eberl S, Daviskas E, Constable C, Young I. Changes in lung deposition of aerosols due to hygroscopic growth: a fast SPECT study. JOURNAL OF AEROSOL MEDICINE : THE OFFICIAL JOURNAL OF THE INTERNATIONAL SOCIETY FOR AEROSOLS IN MEDICINE 2002; 15:307-11. [PMID: 12396419 DOI: 10.1089/089426802760292654] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Our objective was to use rapid dynamic SPECT to study the effect of hygroscopic growth on aerosol deposition in the lung. Six healthy volunteers inhaled radiolabeled ((99m)Tc-DTPA) saline aerosols of two different droplet sizes (MMAD Small 3.2 +/- 0.2 and Large 6.5 +/- 0.2 microm, span 1.8 and 1.7, respectively) and tonicities (normal saline, NS, 0.9% and hypertonic saline 'HS' 7.0% NaCl) reproducibly on 4 occasions. Simultaneous emission-transmission scanning with a triple detector gamma camera was used to collect the lung images. Regional lung deposition was quantified by the penetration index or PI. The results revealed significant differences of aerosol deposition in the lung, which follows precisely the expectation from particle size and hygroscopicity. The difference in the PI values between the aerosols increases in the order of: Large NS-Large HS < Small NS-Small HS < Small HS-Large NS < Small HS-Large HS < Small NS-Large NS < Small NS-Large HS.
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Affiliation(s)
- Hak-Kim Chan
- Faculty of Pharmacy, University of Sydney, Sydney, Australia.
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