Spacer Devices
Hans Bisgaard, Chris O’Callaghan, Gerald C. Smaldone in Drug Delivery to the Lung, 2001
The aerosol cloud from a pressurized metered dose inhaler (pMDI) leaves the canister at a very high speed after actuation. As a result, coordination of actuation and inhalation can be very difficult, resulting in a high aerosol deposition in the oropharynx and variation in the lung dose. Spacers and holding chambers have been developed in an attempt to overcome this problem. In principle, spacers are extensions of the pMDI canister, allowing deceleration and maturation of aerosol, while holding chambers are valved spacers allowing breathing from a standing cloud of aerosol. In clinical practice, the term spacer is used to denote either of such inhalation aids, and this term is used in the present review.
Establishing and Controlling Exposures
Robert F. Phalen in Inhalation Studies, 2009
Modern inhalation studies must conform to rigorous criteria with respect to generation and control of the exposure environment. Pure air, having precisely adjusted temperature and relative humidity, is intentionally polluted with substances having known and stable characteristics. In most well-designed studies, a matched control population of subjects is exposed either simultaneously (preferred) or serially to pure air. One requirement of such studies is the ability to clean and condition quantities of ambient air. To meet this challenge, a suitable air purification and conditioning system must be installed, tested, and successfully operated. Additionally, equipment for generating pollutants must be carefully designed or selected, tested, and then operated successfully during exposures. Furthermore, experience has shown that the manner in which pollutants are combined and mixed with clean throughput air, and the ability to suppress unwanted, animal-generated contaminants, are important to achieving a high-quality exposure.
Testing for Toxicity
Robert F. Phalen in Inhalation Studies, 2009
An organism can respond to pollutant exposure in as many ways as its total number of properties and functions. Thus, if one can define and measure a property or function, it can be used as a biological endpoint in an inhalation study. Furthermore, no matter what is selected for measurement, there will be number of airborne materials that, in sufficient concentration and exposure time, will produce a statistically significant change in the endpoint. But until the role of the measured property is understood in terms of its relationship to harm or disease, one does not know how to treat the result. In other words, it may be a health effect or just basic scientific information.
Inhaled salbutamol from aerolizer and diskus at different inhalation flows, inhalation volume and number of inhalations in both healthy subjects and COPD patients
Published in Experimental Lung Research, 2019
Marian S. Boshra, Ahmed G. Almeldien, Randa Salah Eldin, Ahmed A. Elberry, Nada Sayed Abdelwahab, Mohamed Nabil Salem, Hoda Rabea, Mohamed E. A. Abdelrahim
The aim of the present study was to demonstrate the effect of inhalation-flow, inhalation-volume and number of inhalations on aerosol-delivery of inhaled-salbutamol from two different dry powder inhalers (DPIs) in both healthy-subjects and chronic obstructive pulmonary disease (COPD) patients. Relative pulmonary-bioavailability and systemic-bioavailability of inhaled-salbutamol, delivered by Diskus and Aerolizer, was determined in 24-COPD patients and 24-healthy subjects. The healthy-subjects and the COPD-patients participated in the study for 7 days in which they received 4 study doses of 200 μg salbutamol (one slow-inhalation, two slow-inhalations, one fast-inhalation, and two fast-inhalations) in four alternative days with 24 hr washout period after each dose. Two urine-samples were collected from each study subjects. The first was provided 30 min post inhalation (USAL0.5), as an index of relative pulmonary-bioavailability, and the second was pooled to 24 hr post inhalation (USAL24), as an index of systemic-bioavailability. Fast-inhalation resulted in significantly higher USAL0.5 and USAL24 than slow-inhalation (p
Amyl Nitrite Alters Human in Vitro Immune Function
Published in Immunopharmacology and Immunotoxicology, 1991
E. M. Dax, W. H. Adlei, J. E. Nagel, W. R. Lange
Effects on the human immune system of volatile nitrite inhalation were studied in 18 male volunteers. While nitrite inhalation decreased the absolute number of CD3+ T lymphocytes during the period of inhalation, cell numbers returned to pre-treatment levels within one week after cessation of the drug. Nitrite inhalation did not alter the percentage of CD3+, CD4+, CD8+ or CD19+ lymphocytes. Natural killer (NK) cell activity against K562 target cells was depressed by nitrite administration but returned to pre-inhalation or greater levels after nitrite discontinuation. Cell proliferation following cell activation by PHA, ConA and PWM was unaffected by amyl nitrite inhalation. We conclude that in humans inhalation of volatile nitrites causes cycles of modest immunosuppression, particularly in NK activity, followed by gradual recovery when the drug is not inhaled for several days.
Total emitted dose of salbutamol sulphate at different inhalation flows and inhalation volumes through different types of dry powder inhalers
Published in Experimental Lung Research, 2018
Marian S. Boshra, Ahmed G. Almeldien, Randa Salah Eldin, Ahmed A. Elberry, Nada Sayed Abdelwahab, Mohamed Nabil Salem, Hoda Rabea, Mohamed E. A. Abdelrahim
The aim of the present study was to compare the performance of two different dry powder inhalers (DPIs) at different inhalations volumes and inhalation flows. Ventolin Diskus contain blisters of 200µg salbutamol. To test the TED from Aerolizer, salbutamol in Diskus blister was emptied and placed in size 3 capsules suitable for use with Aerolizer. Total emitted dose (TED) delivered by Diskus and Aerolizer was determined using DPI sampling apparatus after one and two inhalations from the same dose. 10-60L/min inhalation flows at 2 and 4L inhalation volume were used in the determination. At inhalation flow ≤30L/min, two inhalations resulted in higher TED than one inhalation (p