Oropharyngeal Deposition and Delivery Aspects of Metered-Dose Inhaler Aerosols: Reply

Kim, Chong S.; Eldridge, M. A.; Sackner, Marvin A.

doi:10.1164/ajrccm/137.4.986

Cited by 13 publications

(18 citation statements)

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“…However, the use of pMDIs is associated with a number of problems, which have limited their effectiveness. The most important problems are co-ordination difficulties, and high oropharyngeal deposition resulting from pMDI actuation directly into the mouth [1]. These problems have been greatly reduced by the development of spacer devices [2,3].…”

Section: Technical Notementioning

confidence: 99%

Electrostatic charge on a plastic spacer device influences the delivery of salbutamol

Wildhaber

Devadason²,

Hayden³

et al. 1996

Eur Respir J

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E El le ec ct tr ro os st ta at ti ic c c ch ha ar rg ge e o on n a a p pl la as st ti ic c s sp pa ac ce er r d de ev vi ic ceABSTRACT: The aim of this study was to determine whether electrostatic charge on a plastic spacer decreases the delivery of salbutamol from a pressurized metereddose inhaler (pMDI) and, if so, to find an optimal and practical treatment to remove the charge. Ten single actuations from a salbutamol pMDI were drawn through different Volumatic® spacers at a constant flow of 60 L·min -1 . The efficacies of different methods of removing charge were tested, including detergent coating of the spacers. A multistage liquid impinger was used to determine the particle size distribution of the output of the pMDI through the Volumatic® spacers. The electrostatic charge on the inner surface of the spacers was measured both quantitatively with an electrometer, and qualitatively by the attraction of a thin strip of cellulose membrane to the wall of the spacer. Each experiment was repeated four times.Ionic detergent coating of the spacers removed the charge for at least 24 h. This resulted in an increase of 55-70% in small particle (<6.8 µm) delivery compared to delivery from new spacers with high charge.We have demonstrated that electrostatic charge plays a major role in the delivery of salbutamol through plastic spacers. Adequate treatment with ionic detergent removes the charge and improves drug delivery.

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Section: Technical Notementioning

confidence: 99%

Electrostatic charge on a plastic spacer device influences the delivery of salbutamol

Wildhaber

Devadason²,

Hayden³

et al. 1996

Eur Respir J

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“…The oropharyngeal model used in the present study has shape and dimensions similar to an adult oropharyngeal cavity, and has been used to test metered-dose inhalers [7]. The model may not represent all true clinical situations but may be considered to be a fair representation of a typical situation.…”

Section: Discussionmentioning

confidence: 99%

“…The oropharyngeal model was made with glass according to the anatomical dimensions of a human adult, and was previously used to estimate oropharyngeal deposition of aerosols from metered-dose inhalers [7]. The oropharyngeal model had a uvula at the entrance to the pharynx; the distance from the opening of the mouth to the back of the pharynx was 10 cm and the volume of the mouth cavity was about 90 mL.…”

Section: Methodsmentioning

confidence: 99%

Actual pentamidine dose delivered by Respigard II nebulizer

1995

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and a substantial amount of solution was left unused in the nebulizer. This differs from the FDA guideline that recommends a complete nebulization until the chamber is empty. In recent studies [6], delivery of pentamidine from the RPG II was measured as a function of time until dryness. Operation of the nebulizer, however, was interrupted every 5 min to collect samples, which could alter the delivery characteristics of the nebulizer.The purpose of the present study was to determine the delivered dose of pentamidine aerosol with continuous operation of the nebulizer until dryness. Delivered dose was measured with and without an oropharyngeal model to investigate the influence of the upper airways. The results of the present study may supplement the previous results and may be used as the basis of comparing different delivery systems and of interpreting the therapeutic effect of pentamidine aerosol. Materials and methods Respigard II nebulizer system (RPG II)The system consists of an air jet nebulizer, a Y-piece with two one-way valves installed at the inspiratory and expiratory limbs, an expiratory filter, and a mouthpiece ( fig. 1). The nebulizer is connected to the side of the inspiratory limb of the Y-piece via a T-connector. A short corrugated hose and a one-way valve are attached to the inlet port of the T-connector. During operation, aerosols are generated continuously with compressed air at 7.25 kPa, at which a jet airflow rate of 6 L·min -1 is ABSTRACT: The Respigard II nebulizer system is the approved method to deliver pentamidine aerosols in the USA. Although continuous operation of the nebulizer until dryness is a designated regimen, the actual pentamidine dose delivered under the operating condition has not been thoroughly studied. Pentamidine solutions (300 mg in 6 mL water) were nebulized continuously with the Respigard II nebulizer system until dryness (40 min operation). Aerosols were delivered to the lower airways via an oropharyngeal model and sampled on a filter with a standard breathing mode of 20 breaths·min -1 frequency and 750 mL tidal volume. Intermediate samples were also obtained for the initial 20 min delivery.The pentamidine dose delivered to the mouth was 1.6% of the dose placed in the nebulizer. Of the dose delivered to the mouth, 92% was delivered during the initial 20 min period. Aerosol loss in the oropharyngeal model was 15% of the dose delivered to the mouth or 0.24% of the dose initially placed in the nebulizer.Pentamidine dose delivered to the lower airways was a very small fraction of the initial dose in the nebulizer. A partial delivery for the initial 20 min was nearly comparable to complete delivery.

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“…A number of measurements have been made of drug available from different spacers used with a variety of MDI drugs. While, for a particular MDI drug, the particle size characteristics of the available aerosol are similar from different spacers, the dose of the drug available is different (Kim et al 1987;Dolovich et al 1993;Ahrens, personal communication). The fraction of the label claim available at the spacer exit also varies with the drug, as illustrated in Fig.…”

Section: Spacersmentioning

confidence: 99%

Characterization of Medical Aerosols: Physical and Clinical Requirements for New Inhalers

Dolovich

1995

Aerosol Science and Technology

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Oropharyngeal Deposition and Delivery Aspects of Metered-Dose Inhaler Aerosols: Reply

Cited by 13 publications

References 0 publications

Electrostatic charge on a plastic spacer device influences the delivery of salbutamol

Electrostatic charge on a plastic spacer device influences the delivery of salbutamol

Actual pentamidine dose delivered by Respigard II nebulizer

Characterization of Medical Aerosols: Physical and Clinical Requirements for New Inhalers

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