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Practices of coating collection surfaces of cascade impactors: A survey of members of the european pharmaceutical aerosol group (EPAG)
... Because the amount of aerosol in the largest size fraction was small and because of possible losses due to settling of the large aerosol particles, data for the largest size fraction was not included in the analysis. The impactor collection plates were coated with a solution of glycerol and Brij 35 to prevent particles from bouncing off the plates during collection (Mitchell 2003). After aerosol collection was completed, the impactor plates were rinsed with 0.1 M Tris solution and the fluorescence of the solution was measured using a fluorometer (SpectraMax M4, Molecular Devices). ...
Face masks are recommended to reduce community transmission of SARS-CoV-2. One of the primary benefits of face masks and other coverings is as source control devices to reduce the expulsion of respiratory aerosols during coughing, breathing, and speaking. Face shields and neck gaiters have been proposed as an alternative to face masks, but information about face shields and neck gaiters as source control devices is limited. We used a cough aerosol simulator with a pliable skin headform to propel small aerosol particles (0 to 7 µm) into different face coverings. An N95 respirator blocked 99% (standard deviation (SD) 0.3%) of the cough aerosol, a medical grade procedure mask blocked 59% (SD 6.9%), a 3-ply cotton cloth face mask blocked 51% (SD 7.7%), and a polyester neck gaiter blocked 47% (SD 7.5%) as a single layer and 60% (SD 7.2%) when folded into a double layer. In contrast, the face shield blocked 2% (SD 15.3%) of the cough aerosol. Our results suggest that face masks and neck gaiters are preferable to face shields as source control devices for cough aerosols.
... Because the amount of aerosol in the largest size fraction was small and because of possible losses due to settling of the large aerosol particles, data for the largest size fraction was not included in the analysis. The impactor collection plates were coated with a solution of glycerol and Brij 35 to prevent particles from bouncing off the plates during collection (Mitchell 2003). After aerosol collection was completed, the impactor plates were rinsed with 0.1 M Tris solution and the fluorescence of the solution was measured using a fluorometer (SpectraMax M4, Molecular Devices). ...
Face masks are recommended to reduce community transmission of SARS-CoV-2. One of the primary benefits of face masks and other coverings is as source control devices to reduce the expulsion of respiratory aerosols during coughing, breathing, and speaking. Face shields and neck gaiters have been proposed as an alternative to face masks, but information about face shields and neck gaiters as source control devices is limited. We used a cough aerosol simulator with a pliable skin headform to propel small aerosol particles (0 to 7 µm) into different face coverings. An N95 respirator blocked 99% of the cough aerosol, a medical grade procedure mask blocked 59%, a 3-ply cotton cloth face mask blocked 51%, and a polyester neck gaiter blocked 47% as a single layer and 60% when folded into a double layer. In contrast, the face shield blocked 2% of the cough aerosol. Our results suggest that face masks and neck gaiters are preferable to face shields as source control devices for cough aerosols.
... Because the amount of aerosol in the largest size fraction was small and because of possible losses due to settling of the large aerosol particles, data for the largest size fraction was not included in the analysis. The impactor collection plates were coated with a solution of glycerol and Brij 35 to prevent particles from bouncing off the plates during collection (Mitchell 2003). After aerosol collection was completed, the impactor plates were rinsed with 0.1 M Tris solution and the fluorescence of the solution was measured using a fluorometer (SpectraMax M4, Molecular Devices). ...
Face masks are recommended to reduce community transmission of SARS-CoV-2. One of the primary benefits of face masks and other coverings is as source control devices to reduce the expulsion of respiratory aerosols during coughing, breathing, and speaking. Face shields have been proposed as an alternative to face masks, but information about face shields as source control devices is limited. We used a cough aerosol simulator with a headform to propel small aerosol particles (0 to 7 µm) into different face coverings. An N95 respirator blocked 99% of the cough aerosol, a procedure mask blocked 59%, a 3-ply cloth face mask blocked 51%, and a polyester neck gaiter blocked 47% as a single layer and 60% when folded into a double layer. In contrast, the face shield blocked 2% of the cough aerosol. Our results suggest that face masks and neck gaiters are preferable to face shields as source control devices for cough aerosols.
... The outcome of this survey was published at Drug Delivery to the Lungs 14 [2], and highlighted the variety of acceptable coating practices currently in use. Standardisation of coating procedure, though possibly attractive in terms of providing a common approach, was therefore considered unnecessary, given that each technique in use is fully validated by each company and is based upon the requirements of their own formulations and impactor design that they employ. ...
The Impactor Sub-Team was formed in Oct 2003 after EPAG had sponsored a pharmaceutical industry-wide collaborative study to assess the performance of the commercial Next Generation Impactor (NGI). The primary aim of the group has been to provide a forum for the investigation of practical issues relating to impactor testing within the pharmaceutical industry, to identify key issues for further investigation and to establish best practice, reporting its findings to the plenary EPAG committee. The activities of the Impactor sub-team are described. These have included surveys of impactor use and studies such as stage mensuration, air leakage and flow rate control. Topics of interest identified by the sub-team for further study are also indicated.
... The decision whether or not to coat, and with whatever substrate, is normally made during the development of the method for a particular inhaler/drug product 42 KONA No.22 (2004) [21]. A wide variety of such methods exist, and the European Pharmaceutical Aerosol Group (EPAG) has therefore recently published a summary of current procedures that are in use by member organizations [85]. Although pMDIs have customarily been tested using uncoated collection surfaces, recent data with the MMI [86], Andersen 8-stage CI [87] and NGI [88,89] indicate that a surface coating may also be necessary when evaluating this class of inhaler with these impactors, especially if the formulation contains no surfactant and only 1 or 2 actuations of the inhaler are performed per measurement to simulate delivery of the clinically prescribed dose. ...
Methods currently in use for the in-vitro measurement of the particle size distribution of aerosols from medical inhalers are reviewed with emphasis on their applicability both for product development and quality control testing and for simulation of likely performance in clinical use. Key attributes and limitations of the various techniques are identified, and consideration is also given both to likely developments to improve the capabilities of these analyzers as well as to the procedures for their use.
... Next Generation Impactors (NGIs) were used according to the procedures given in the USP 30 [27] after mensuration by the supplier (Copley Scientific, Nottingham, UK). Impactor cups were coated using a mixture of Brij 35-p in ethanol with glycerol as described previously [28]. The pre-separator was filled with 15 mL of a suitable solvent for the HPLC analysis. ...
There is increasing interest in the use of so-called 'extrafine' aerosols to target the small airways in the management of asthma and COPD. Using previously presented deposition data, we assessed whether submicron (< 1 μm) particles can improve central and deep lung deposition. Our data show instead that particles in the range 1-3 μm are much more relevant in this respect. Based on this finding the Symbicort Turbuhaler, Seretide Diskus, Rolenium Elpenhaler and Foster (Fostair) NEXThaler ICS/LABA combination DPIs were tested in vitro as a function of the pressure drop (2, 4 and 6 kPa) across the inhaler. Obtained fine particle fractions (FPFs) < 5 μm (as percent of label claim) were divided into subfractions <1. 1-3 and 3-5 μm. Differences of up to a factor of 4 were found between the best (Turbuhaler) and worst performing DPI (Elpenhaler), particularly for the FPF in the size range 1-3 μm. The NEXThaler, described as delivering 'extrafine' particles, did not appear to be superior in this size range. The marked differences in amount and size distribution of the aerosols between the devices in this study must cause significant differences in the total lung dose and drug distribution over the airways.
Copyright © 2015. Published by Elsevier B.V.
Co-administration of an inhaled corticosteroid and long acting beta agonist forchronic obstructive pulmonary disease has reduced mortality compared to either drug alone. This combination reduces exacerbations, hospitalization, emergency department visits and health care costs. A novel fixed-dose combination of the long acting beta-2 agonist salmeterol xinafoate (SX) and the corticosteroid mometasone furoate (MF) were prepared in a composite particle formulation as brittle matrix powder (BMP) and investigated for suitability as an inhaled combination product. In this study, BMP fixed dose combinations of SX and MF with or without stabilizing excipients (lactose, mannitol, glycine and trehalose) were prepared and characterized with respect to their thermal properties, morphology, aerodynamic performance and physical stability. BMP combination formulations of SX and MF exhibited improved aerodynamic properties when delivered by dry powder inhalation as compared to the micronized blends of the same substances. Aerodynamic evaluation was carried out by next generation pharmaceutical impactor (NGI) with a marketed DPI device. Results demonstrated that co-deposition occurred when SX and MF were formulated together as composite particles in a BMP, while physical blends resulted in inconsistent deposition and dose uniformity. As a result of the bottom-up particle engineering approach, combination BMP formulations allow for dual API composite formulations to be dispersed as aerosolized particles. Aerosolized BMP combination formulations resulted in delivered dose uniformity and co-deposition of each API. Further, an excipient-free formulation, BMP SXMF, delivered approximately 50% of the loaded dose in the respirable range and demonstrated stability at ambient conditions for 6 months. Single dose 24-hpharmacokinetic studies in rats demonstrated that lung tissue deposition and blood circulation (AUC0-24) of two APIs were higher for the BMP combination group exhibiting a significantly higher lung concentration of drugs than for the crystalline physical blend. While high system drug levels are generally undesirable in lung targeted therapies, high blood levels in this rodent study could be indicative of increased pulmonary tissue exposure using BMP formulations.
Copyright © 2015. Published by Elsevier B.V.
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