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At least 19 recordsLinked to original sources
PubMed1976

Fluorocarbon aerosol propellants X: pharmacokinetics of dichlorotetrafluoroethane in dogs.

An intravenous dosage form of dichlorotetrafluoroethane, a common fluorocarbon aerosol propellant, was formulated in polyethylene glycol 400 for single dosing to unanesthetized dogs. A three-compartment open model was proposed for the disposition of this compound in dogs, with average half-lives of 1.3, 9.6, and 50.8 min for the three disposition phases. An analysis of tissue compartment distribution following a single dose showed that it took about 2 hr to achieve pseudo-distribution equilibration, following which more than 90% of the propellant remaining in the body was retained in the tissue compartments. Pulmonary clearance and volumes of distribution were calculated considering the first-pass effect through the lungs. The volume of distribution was approximately 10 times the body weight in terms of blood concentration, and about 84% of the propellant was cleared from the blood passing through the lungs in each cycle.

Aerosol Propellants↗
PubMed1975

Fluorocarbon aerosol propellants IV: pharmacokinetics of trichloromonofluoromethane following single and multiple dosing in dogs.

An intravenous dosage form of trichloromonofluoromethane, a common aerosol propellant, was formulated in polyethylene glycol 400 for single and multiple dosing to unanesthetized dogs. A three-compartment open model was proposed for disposition of this compound in dogs with average half-lives of 3.2, 16, and 93 min for three disposition phases. This finding is contrary to several reports where blood levels were monitored for shorter periods. A computer analysis of tissue compartment distribution following a single dose showed that about 2 hr was required to achieve pseudodistribution equilibration, following which more than 90% of the dose remaining in the body was retained in tissue compartments. Pulmonary clearance and volumes of distribution were calculated considering first-pass effect through the lung. The volume of distribution was approximately six times the body weight in terms of blood concentrations, and about 30% of the propellant was cleared from blood passing through the lung in each cycle. Disposition of propellant followed dose-independent kinetics after multiple dosing, and accumulation in tissues continued for a much longer period, resulting in high tissue compartment levels.

Aerosol Propellants↗
PubMed1975

Fluorocarbon aerosol propellants. VI: Interspecies differences in solubilities in blood and plasma and their possible implications in toxicity studies.

Solubilities of the three most commonly used fluorocarbon aerosol propellants were determined in the blood and plasma of humans, monkeys, dogs, rats, and mice. Differences as large as approximately fourfold in blood and more than 33-fold in plasma were found in different species. The partitioning of fluorocarbons between blood cells and plasma showed even greater differences between species. An indirect method was suggested for the calculation of plasma concentrations from total blood concentrations. A comparative evaluation was reported for the nonprotein bound fractions of fluorocarbons in the blood samples of various species. A correlation was drawn for the pharmacokinetic properties of the fluorocarbons within and between species, and a rationale was provided for the extrapolation of toxicity data from animals to humans.

Adult↗
PubMed1971

Ventricular arrhythmias induced in monkeys by the inhalation of aerosol propellants.

After inhaling fluoroalkane gases, which are used as aerosol propellants, some people have died suddently and unexpectedly. Seeking an explanation, we had 14 monkeys inhale these gases. All developed ventricular premature beats, bigeminy, or tachycardia, which began at an average of 39 (SE +/-4.2) sec. Fluoroalkanes were present in blood, but arterial hypoxemia or hypercapnia was absent, and arterial pressure was reduced only slightly. In contrast, without fluoroalkanes, 3 min of asphyxia or anoxia caused arrhythmias in only one monkey whose arterial oxygen tension had fallen to 16 mm Hg. The ventricular arrhythmias caused in well oxygenated monkeys by fluoroalkane gases may either be mediated through beta adrenergic receptors, since propranolol abolished these arrhythmias, or result from a nonadrenergic, direct, toxic effect of these gases on the heart. These results suggest that some deaths after propellant inhalation may be caused by ventricular tachycardia or fibrillation.

Aerosols↗
PubMed2005

Alternative propellant aerosol delivery systems.

The year 2006 represents the 50th anniversary of the pressurized metered dose inhaler. With most technologies, 50 years represents a significant time span for technology evolution and modification, but with propellant-driven metered dose inhalers, the pace of change has been relatively slow. We are now in the era of alternative propellant aerosol delivery systems, but at this 50-year juncture, what are the characteristics of these systems and what are the prospects for future advances? This review will consider alternative propellant aerosol delivery systems broadly from their inception through future opportunities and challenges.

Aerosols↗
PubMed1975

Cardias arrhythmias in hypoxic rabbits during aerosol propellant inhalation.

Rabbits were exposed for four minutes to combinations of oxygen (21%, 11%, or 7%) and fluorocarbon-11 (0%, 5%, or 15%). Exposure to 7% oxygen-15% fluorocarbon-11 caused cardiac arrhythmias in all rabbits exposed. These bradyarrhythmias developed at levels of arterial hypoxemia that did not cause arrhythmias in rabbits exposed to 7% oxygen alone. In contrast with recent reports, hypoxia and this aerosol propellant do appear to have an interactive effect on cardiac rhythm.

Aerosol Propellants↗
PubMed1975

Hemodynamic effects of aerosol propellants. I. Cardiac depression in the dog.

The inhalation of fluorocarbons caused a depression of myocardial contractility, aortic hypotension, a decrease in cardiac output and an increase in pulmonary vascular resistance. The minimal concentrations that elicited these changes are as follows: 1% trichlorofluoromethane (FC11); 2.5% dichlorotetrafluoroethane (FC114); and 10% dichlorodifluoromethane (FC12). Inhalation of 20% octafluorocyclobutane (FC318) and difluoroethane (FC152a) did not influence these hemodynamic parameters. As in previous comparisons, the most widely used aerosol propellants are potentially cardiotoxic in the anesthetized dog.

Aerosol Propellants↗
PubMed1991

The effects of bronchodilator-inhaler aerosol propellants on respiratory gas monitors.

Spurious readings from a mass spectrometer have been reported following the administration of aerosol bronchodilators. We quantified the response of various respiratory gas analyzers to the aerosol propellant of albuterol inhalant (Proventil). The mass spectrometer systems tested, two Advantage systems, a SARA system, and a Model 6000 Ohmeda system, all displayed artifactual readings in response to the albuterol propellant. Each metered dose of the Proventil brand of albuterol contains 4 ml of Freon 11 (trichloromonofluoromethane) and 11 ml of Freon 12 (dichlorodifluoromethane). The concentration of propellant was expressed in doses/L, where each liter of gas contains 0.4 vol % of Freon 11 and 1.1 vol % of Freon 12 per dose. In proportion to the concentration of albuterol propellant, the two Advantage systems showed substantial readings of isoflurane (%) when no isoflurane was present (13% and 16% per dose/L) and reduced readings of enflurane (-8% and -10% per dose/L) and carbon dioxide (CO2) (-3 and +5 mm Hg per dose/L). The SARA system showed substantial CO2 readings when no CO2 was present (5 mm Hg per dose/L) and displayed small enflurane readings (0.1% per dose/L) when no enflurane was present. The Model 6000 unit showed CO2 readings when no CO2 was present (5 mm Hg per dose/L). Neither the Raman spectrometer, the infrared spectrometers, nor the piezoadsorptive analyzer we tested showed an artifactual effect of albuterol propellant on any of its readings. Simulation and clinical tests demonstrated that a single dose of albuterol propellant into a breathing circuit at the onset of inspiration resulted in concentrations of 0.8 and 0.3 dose/L, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Aerosol Propellants↗
PubMed1979

[Do aerosol propellants produce a bronchoconstrictor effect? (author's transl)].

25 asthma patients regularly showed an increase in respiratory resistance, as measured by the oscillation method, after propellant from a dosage aerosol had been sprayed into their buccal or nasal cavity. This effect, which was also seen in three laryngectomised patients, could be blocked by ipratropium bromide, an anticholinergic agent. Evidently it is due to a bronchoconstrictor reflex elicited by the local low-temperature stimulus produced by the propellant.

Adult↗
PubMed2004

Medical aerosol propellant interference with infrared anaesthetic gas monitors.

BACKGROUND: 1,1,1,2 Tetrafluoroethane is a hydrofluoroalkane (HFA) that is replacing chlorofluorocarbons (CFC) as a medical aerosol propellant in an attempt to reduce damage to the ozone layer. This study compared the effects of HFA- and CFC-based inhalers on four anaesthetic gas monitoring systems. METHODS: The HFA- and CFC-based inhalers were activated in close proximity to the sample line of two Datex Ohmeda, an Agilent and a Siemens infrared anaesthetic agent monitoring systems. The effects were recorded on each system for five common anaesthetic agents. RESULTS: The HFA inhaler caused either maximal false positive readings (with the exception of desflurane) or transient measurement failure on all systems. The Datex Ohmeda AS/3 system misidentified the HFA inhaler as carbon dioxide at low concentration (2 +/- 0 mm Hg). The CFC-based inhaler caused a minor false-positive reading (0.4 +/- 0%) for halothane only on the Datex Ohmeda AS/3 system only and was misidentified as carbon dioxide at 33.3 (sd 2.1) mm x Hg and 22.4 (8.9) mm x Hg by the Agilent and Siemens systems. CONCLUSIONS: The HFA inhaler adversely affected all equipment tested. The infrared spectra of HFA and the common anaesthetic gases have considerable overlap at the 8-12 microm range that is not shared by the CFCs. The differences in spectral overlap explain the different effects of the HFA and CFC propellants. Anaesthetic gas concentration data may be erroneous using the HFA-based inhalers.

Aerosol Propellants↗