Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “AEROSOLS”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 847 records · Page 47Linked to original sources
PubMed2001

Bacterial aerosols in the dental clinic: a review.

A number of sources of bacterial aerosols exist within and outside the dental clinic. The concentration of bacterial aerosols and splatters appears to be highest during dental procedures, especially those generated by some procedures such as ultrasonic scaling, or using a high speed drill. Several infectious diseases could be transmitted to staff and patients by airborne bacterial and other contaminants in the dental clinic. Air-conditioning and ventilation systems should be regularly maintained to reduce environmental contaminants and to prevent recirculation of bacterial aerosols. Pre-procedural rinsing by patients with mouthwashes as well as vacuum and electrostatic extraction of aerosols during dental procedures could also be employed. Dental staff should also consider appropriate immunizations and continue to use personal protective measures, which reduce contact with bacterial aerosols and splatters in the dental clinic.

Aerosols↗
PubMedDate not supplied

Safety aspects and pharmacokinetics of inhaled aerosolized gadolinium.

This study evaluated the pharmacokinetics and potential toxicity of inhaled aerosolized gadopentetate dimeglumine. The pharmacokinetics were evaluated with in vitro relaxometry of the lungs, blood, urine, and liver before and for up to 36 hours after a 5-minute inhalation of aerosolized gadopentetate dimeglumine (0.25 mol/L). For assessment of potential toxicity, hemodynamic variables were monitored during and for 10 minutes after inhalation. Extravascular lung water was measured before and after exposure. Finally, the potential for tissue damage was evaluated histologically. Pulmonary clearance of aerosolized gadopentetate dimeglumine was monoexponential with a half-time of 2.16 hours. Aerosolized gadopentetate dimeglumine was excreted through the kidneys, as shown by the decrease in urinary T1. Renal elimination was completed by 30 hours. No acute hemodynamic effect, histologic change, or induction of edema was demonstrated. This study shows that inhalation of aerosolized gadopentetate dimeglumine is well tolerated in rats and favors the further evaluation of this administration route, including clinical trials.

Aerosols↗
PubMed2005

Artificial neural network prediction of the patterns of deposition of polydisperse aerosols within human lungs.

For optimum therapeutic response from drug administered to the lungs, it is paramount that the aerosolised drug is able to deposit in the lower airways. The filtering characteristics of the respiratory tract, however, make this a particularly challenging task. Computational tools afford a cost-effective means of studying the problem, and here we report on the development of a rapid and reliable method for predicting the pattern of deposition of polydisperse aerosols within human lungs using artificial neural networks (ANNs). Literature (experimental) data on lung deposition of monodisperse aerosols were used to train a single ANN to allow for simultaneous predictions of regional and total aerosol particle deposition patterns in human lungs. When used in modelling the fate of polydisperse aerosols in human lungs, the trained ANN was found to give highly accurate predictions for all lung regions, and all (pharmaceutically relevant) particle sizes and breathing conditions (with errors typically <0.025%). Further testing of the ANN, using 'unseen' in vitro and in vivo data, gave good agreement of lung dosages. It is thus concluded that the ANN produced can be used to provide highly reliable estimates of particle deposition from polydisperse pharmaceutical aerosols generated from breath-actuated dry powder inhalers, nebulizers and metered dose inhalers with spacers.

Aerosols↗
PubMed1976

Development of an aerosol dosage form containing insulin.

An aerosol dosage form containing insulin was developed by suspending insulin zinc crystals in fluorocarbon propellant and using oleyl alcohol to improve the insulin suspension and to prevent valve clogging. A metered valve was used to control the amount of insulin delivered per actuation. The dose dispensed, sedimentation rate, and particle-size distribution of the aerosol formulation were evaluated. The potency of the insulin delivered from the aerosol containers stored at various temperatures and time intervals was determined using a radioimmunoassay. Based upon preliminary stability data, which were treated kinetically, it was noted that insulin aerosols stored in a refrigerator at 7 degrees would have a predicted shelflife of approximately 19 years, whereas samples stored at 25 and 37 degrees would have shelflives of 11 and 2 months, respectively. Long-term stability studies are indicated to establish this conclusion. On the basis of this study, it was concluded that an insulin-containing aerosol dosage form can be formulated and that a suitable dose of insulin can be dispensed using commercially available metered dose valves. The actual dose of insulin dispensed would have to be related to the degree of absorption of insulin one would normally expect when insulin is administered by the inhalation route.

Aerosols↗
PubMed1983

Characterization of spray patterns of inhalation aerosols using thin-layer chromatography.

The spray pattern of an inhalation aerosol was characterized using photography and by observing the impaction pattern on a TLC plate. The aerosol plume was conical in shape, and its cross section increased with increasing distance from the actuator. Three puffs of the aerosol, at a distance of 3 cm between actuator and the TLC plate, produced a spot that had approximately the same diameter as the cross section of the aerosol plume at that distance from the actuator. The TLC technique with these parameters was selected to develop an assay characterizing the spray pattern of an inhalation aerosol because of its specificity, simplicity, and speed.

Aerosols↗
PubMed1984

Labeling suspended aerosol particles with short-lived radionuclides for determination of particle deposition.

Radiotracer techniques were developed to examine parameters that characterize pressurized aerosols designed to deliver insoluble particles suspended in the aerosol formulation. Microaggregated bovine serum albumin microspheres that were to be suspended were labeled with iodine-131 (t1/2 = 8 d). This iodination procedure (greater than 80% effective) is also applicable to iodine-123, which possesses superior characteristics for external imaging and further in vivo studies. This report shows that for pressurized aerosols containing suspended particles, each metered dose is approximately equal (not including the priming doses and the emptying doses). Increase in the delivery of the albumin particles out of the canister was best achieved by pretreating the valve assembly with a solution of 2% (w/v) bovine serum albumin in phosphate buffer. Use of a cascade impactor delineated the particle size distribution of the micropheres, with the majority of particles ranging in size from 2 to 8 microns. The data disclosed here indicate that the techniques developed with short-lived radionuclides can be used to quantitate each metered dose, characterize the particle size distribution profile of the aerosol contents, and determine the extent of deposition of the particles in the aerosol canister and all of its components.

Aerosols↗
PubMed1986

An isolated perfused rat lung preparation for the study of aerosolized drug deposition and absorption.

The isolated, perfused rat lung preparation was modified to allow characterized solid aerosol delivery. Deposition and airway-to-perfusate transfer of disodium fluorescein from 3-4 micron dae solid aerosols were studied under different ventilatory regimes. The lungs inhaled from an aerosol stream of constant concentration via a tracheal cannula. Air displacement from a sealed artificial thorax housing the lungs provided the driving force for inhalation. The lungs were suspended in a physiologically normal position and both left and right sides of the heart were cannulated for constant rate perfusate flow. Fractional deposition was inversely proportional to respiratory frequency implying that sedimentation was the primary deposition mechanism. Increasing tidal volumes similarly enhanced the ratio of amount deposited/amount administered. Fluorescein transfer to the perfusate occurred from the lung regions containing intact vasculature, was apparent first-order, and independent of perfusate flow. The average rate constant for transfer was 0.057 +/- 0.02 min-1 (t1/2 = 12.2 +/- 4.2 min-1). The ratio of transferable amount/amount deposited appeared to indicate the depth of aerosol penetration. This increased at high respiratory frequency and tidal volume, while decreasing with increasing aerosol particle size. Potential applications of the model are discussed in the light of these results.

Absorption↗
PubMed2001

Comparison of aerosolized gadoteridol and gadopentetate dimeglumine for magnetic resonance ventilation imaging of the lung.

The purpose of this study was to compare aerosolized gadoteridol and gadopentetate dimeglumine in regard to homogeneity of aerosol distribution and relative pulmonary signal intensity (SI) changes after a 10-min mechanical ventilation period. Twenty experimental procedures were performed in 10 intubated domestic pigs that were mechanically aerosolized with the nebulized contrast medium. Images were obtained by using a respiratory-gated T(1)-weighted TSE sequence. Pulmonary SI increase for the right and left lung was 26% +/- 25% and 25% +/- 12%, respectively, for gadopentetate dimeglumine, and 45% +/- 12% and 43% +/- 10%, respectively, for gadoteridol. Aerosol distribution was rated homogeneous in all cases by two readers. It is concluded that both contrast agents in aerosolized form are capable of depicting pulmonary ventilation in healthy animals with lung capacities comparable to those of humans. SI differences between gadoteridol and gadopentetate dimeglumine are explained by their considerable difference in viscosity.

Aerosols↗
PubMedDate not supplied

Aerosol delivery to the rabbit lung with an infant ventilator.

Little is known about delivery of aerosolized medications to infants undergoing assisted positive pressure ventilation. To assess delivery of medications to the lung with an infant ventilator (Bournes LS104), 27 experiments were performed on anesthetized adult rabbits. Lung deposition was determined by using aerosol radiolabeled with 99m technetium sulfur colloid. Initially a traditional nebulizer was studied and very inefficient delivery to the lung was observed (0.19 +/- 0.10 SD% of the initial nebulizer dose). Subsequent experiments using a nebulizer that generates submicronic aerosol particles, at equivalent aerosol output, achieved a highly significant increase in delivery (1.96 +/- 1.19 SD%, P less than 0.001). Our experiments demonstrated that modifications to to traditional nebulizer systems can enhance delivery of aerosolized medication to the lungs of rabbits.

Aerosols↗
PubMed1989

In vitro performance of the small particle aerosol generator (SPAG-2).

The anti-viral drug ribavirin primarily used for the treatment of respiratory syncytial virus (RSV) infection in infants is delivered by continuous nebulization with the Small Particle Aerosol Generator (SPAG). Clinical data suggest that the SPAG is an efficient nebulizer for ribavirin; it is also being used for the delivery of other pulmonary agents. The efficiency of a nebulizer can be defined in large part by delivering a major proportion of its output with a particle size of 1 to 5 microns which is small enough to penetrate the tracheobronchial tree. We assessed both the quality and quantity of the SPAG aerosol cloud with the aid of a multistage liquid impinger, utilizing 2% ribavirin and 1% cromolyn sodium solutions. The aerosol of either solution had a mass median aerodynamic diamter (MMAD) of approximately 1.2 microns, and this seemed insensitive to solution strength and nebulization period. Of the solutions of ribavirin and cromolyn sodium 92.3% and 95.0%, respectively, by weight of delivered particles, had aerodynamic diameters less than 5 microns and about 70-75% of the aerosol particles had an aerodynamic diameter in the 1-5 microns range. This implies that the aerosol cloud is adequate for delivery through a ventilator circuit. Performance was maintained over long (16 hours), continuous periods of delivery. The SPAG could be useful for delivery of other respiratory drugs by continuous nebulization.

Aerosols↗
PubMed1989

Safety of aerosol tobramycin administration for 3 months to patients with cystic fibrosis.

To determine the potential toxicity of prolonged aerosol tobramycin administration, 22 patients with cystic fibrosis were monitored while receiving inhaled tobramycin three times a day for 12 weeks. Prior to, four times during administration and approximately 6 weeks after discontinuation of treatment, we assessed pulmonary function, weight, height, body temperature, eighth cranial nerve function, serum creatinine, blood urea nitrogen, urinary creatinine clearance, plasma iothalamate clearance, urinary beta-2 microglobulin concentration, and Pseudomonas aeruginosa density in sputum. There was no detectable laboratory evidence of nephrotoxicity. Neither a decrease in auditory acuity (range 250-20,000 Hz) nor vestibular dysfunction was detected. Pulmonary function tests significantly improved during the first month in all subjects (P less than 0.05) but returned to enrollment values by the end of the 12th week of administration of tobramycin aerosol. Sputum P. aeruginosa density initially decreased from a mean of 10(7) cfu/gm to a mean of 10(4) cfu/gm after 2 weeks of aerosol tobramycin administration and remained significantly below the enrollment value throughout. Coincident with the reduced bacterial density, a reduction in cough frequency and sputum production, as well as a weight gain was observed. Seventy-three percent of the patients with sputum P. aeruginosa isolates susceptible to tobramycin on enrollment yielded resistant organisms during aerosol administration. However, 1 year later all sputum P. aeruginosa isolates obtained from patients were susceptible to tobramycin. We conclude that thrice daily aerosol tobramycin administration for 3 months is not associated with detectable eighth cranial nerve or renal toxicity. Transient emergence of tobramycin resistant P. aeruginosa may occur.

Administration, Inhalation↗
PubMed1995

AC corona-discharge aerosol-neutralization device adapted to liquid chromatography/particle beam/mass spectrometry.

An AC corona-discharge device was inserted upstream of a thermospray vaporizer tip in a liquid chromatography/particle beam mass spectrometer to neutralize static aerosol charging. Response of a test analyte was measured with or without discharge initiation. If the solvent contained no ammonium acetate buffer, increased analyte signal was associated with the discharge. However, in the presence of ammonium acetate the benefit of AC discharge neutralization was either not observed or was more subtle. This led to the conclusion that the previously observed ammonium acetate "carrier" effect is attributable, at least in part, to neutralization of static electric charges produced spontaneously during the solvent nebulization process. In a second experiment, the pattern of particles issuing from the system momentum separator was examined by aiming the particle beam at a cold target located within a mass spectrometer ion source. Variations in particle density were observed depending on (i) whether or not the aerosol had been neutralized and (ii) the proximity of electron-beam-collimating magnets to the particle beam trajectory. These results are consistent with a hypothesis that electrostatic charging occurs spontaneously during the nebulization process in which an aerosol is formed from the high performance liquid chromatography effluent. Such electrostatic charging introduces a factor likely to degrade system performance by at least two modes: through interactions of the charged aerosol particles (i) with the walls of the aerosol transmission pathway, and, after they are accelerated into a particle beam and introduced into the mass spectrometer, (ii) with the magnets used for electron beam collimation in many mass spectrometer ion sources.

Acetates↗
PubMed1993

Aerosols for therapy and diagnosis.

Aerosols are defined as any mixture of solid or liquid particles/droplets that are stable as a suspension in air. Aerosols influence the lives of a large majority of the population. A proportion of particulates exacerbate or induce lung disease. Other aerosols are used in the prevention or control of lung disease or in the investigation of disease. This review covers the mechanisms of deposition of aerosols, the production and sizing of aerosols, factors affecting the variability in output from nebulisers and the use of radionuclides in defining drug deposition from therapeutic nebulisers.

Adult↗
PubMed1984

Pharmacologic properties of FPL 55712 administered by aerosol.

FPL 55712 was investigated by the aerosol route of administration for efficacy at protecting against leukotriene-induced bronchoconstrictions in guinea pigs and for mediator release inhibitory activity in passively sensitized rats. In the studies to investigate leukotriene antagonism; anesthetized, spontaneously breathing guinea pigs were pretreated with propranolol and were exposed via tracheal cannula to aerosols generated by a Monaghan nebulizer. Subsequently, the animals were artificially ventilated and challenged with LTD4 or LTE4 (25 micrograms/kg, i.v.). FPL 55712 produced a concentration-dependent inhibition of LTD4 and LTE4-induced bronchoconstriction (IC50's 0.5% and 0.8%, respectively). Although the biologic half-life of FPL 55712, administered intravenously, was very short (1.7 minutes against LTD4 and 1.2 minutes against LTE4) after aerosol administration the biological half-life was surprisingly long (120 minutes against LTD4 and 90 minutes against LTE4). Aerosolized FPL 55712 also possessed weak antiallergic activity in comparison to disodium cromoglycate when measured as an inhibitor of IgE-mediated anaphylactic bronchoconstriction in rats (IC50's of 2.0% and 0.01%, respectively). Thus, these studies demonstrate that, when administered by aerosol, FPL 55712 is effective at protecting against leukotriene-induced bronchoconstrictions, exhibits a long duration of action and also possesses weak antiallergic activity.

Aerosols↗
PubMed1987

Pulmonary aerosol actions of LY188695 (KB2413), a new potent H1-receptor antagonist.

The new potent H1 receptor antagonist, LY188695 (KB2413), was delivered to guinea pigs as a pulmonary aerosol and its ability to inhibit histamine-induced airway obstruction examined. Aerosol LY188695 was more effective than inhaled chlorpheniramine or clemastine in reducing the pulmonary gas trapping produced by histamine challenge. Lung antihistamine effects occurred within minutes of a brief, low concentration aerosol exposure and persisted for at least 1 hour. LY188695 aerosol treatment did not produce significant inhibition of methacholine-induced gas trapping. Although systemic antihistamine effects occurred 50 minutes after LY188695 inhalation, aerosol administration produced an enhanced local (i.e., lung) action compared to intravenous delivery.

Aerosols↗
PubMed1988

Antiviral therapy with small particle aerosols.

The generation and use of small particle aqueous aerosols (1.23 microns aerodynamic mass median diameter, GSD = 2.0 microns) containing ribavirin is described. Administered via aerosol, ribavirin will be deposited rather uniformly on the surface of the nasopharynx, the tracheobronchial tree and in the pulmonary area. Examples of aerosol-delivered dosages found to be effective in the treatment of respiratory syncytial virus infection and influenza A and B virus infections are as follows: 12.8 mg of ribavirin/hour for a 6-month-old infant weighing 7.5 kg, and 56.2 kg of ribavirin/hour for a 25-year-old adult weighing 62.5 kg. Drugs which are relatively insoluble in aqueous solutions can also be administered in small particle aerosol by using liposomes as a vehicle. The preparation of enviroxime, a potent anti-rhinovirus drug, in liposomes for aerosol use is reported here. Its antiviral activity in liposomes was found to be undiminished, but its cellular toxicity was greatly reduced. It was well-tolerated by normal volunteers and studies are planned to determine its clinical efficacy.

Aerosols↗
PubMed1996

Aerosolized prostacyclin and inhaled nitric oxide in septic shock--different effects on splanchnic oxygenation?

OBJECTIVES: To compare the effects of inhaled nitric oxide and aerosolized prostacyclin (PGI2) on hemodynamics and gas exchange as well as on the indocyanine-green plasma disappearance rate and gastric intramucosal pH in patients with septic shock. DESIGN: Prospective, randomized, interventional clinical study. SETTING: Intensive care unit in a university hospital. PATIENTS: Sixteen patients with pulmonary hypertension and septic shock according to the criteria of the ACCP/SCCM consensus conference all requiring norepinephrine and/or epinephrine to maintain mean arterial blood pressure above 65 mmHg. METHODS AND INTERVENTIONS: Patients were randomly assigned to receive either nitric oxide or aerosolized prostacyclin. Nitric oxide was inhaled using a commercially available delivery system, prostacyclin was administered with a modified ultrasound nebulizer. Both nitric oxide and prostacyclin were incrementally adjusted to obtain a 15% decrease of mean pulmonary artery pressure. Hemodynamics and gas exchange as well as indocyanine-green plasma disappearance rate and gastric intramucosal pH were determined at baseline after 90 min in steady state, after 90 min of nitric oxide inhalation or prostacyclin aerosol administration had elapsed in stable conditions, and after 90 min in stable conditions after nitric oxide or prostacyclin withdrawal. RESULTS: Both inhaled nitric oxide and aerosolized prostacyclin selectively reduced the mean pulmonary artery pressure from 35 +/- 4, 30 +/- 4 mmHg (p < 0.05) and 34 +/- 4 to 30 +/- 3 mmHg (p < 0.05) respectively; after removal of nitric oxide and prostacyclin, the mean pulmonary artery pressure returned to the baseline values. Systemic hemodynamics remained unaltered during the vasodilator treatment. While the mean PaO2 was not significantly influenced, it increased in 4/8 of the NO- and 3/8 of the PGI2-treated patients. Neither of the drugs influenced indocyanine-green plasma disappearance rate, but prostacyclin--unlike nitric oxide--significantly increased gastric intramucosal pH (from 7.26 +/- 0.07 to 7.30 +/- 0.05, p < 0.05) which remained elevated in four of these patients after prostacyclin removal, and decreased the arterial-gastric mucosal pressure of carbon dioxide gap from 19 +/- 6 to 15 +/- 4 mmHg (p < 0.05). CONCLUSIONS: Our data suggest that aerosolized prostacyclin--unlike nitric oxide--has similar beneficial effects on splanchnic perfusion and oxygenation as intravenous prostacyclin without detrimental effects on systemic hemodynamics. The different effects of prostacyclin and nitric oxide might be explained by the longer half-life of prostacyclin associated with a certain spillover into the systemic circulation.

Administration, Inhalation↗
PubMed1993

99mTc-DTPA aerosol for same-day post-perfusion ventilation imaging: results of a multicentre study.

A multicentre study was performed in an attempt to evaluate a submicronic technetium-99m diethylene triamine penta-acetic acid aerosol generated by a newly developed delivery system, the aerosol production equipment (APE nebulizer), for same-day post-perfusion ventilation imaging in patients with clinically suspected pulmonary embolism. Quantitative comparison between the DTPA aerosol and krypton gas demonstrated a close correlation with respect to regional pulmonary distribution of activity and peripheral lung penetration (n = 14, r = 0.94, P < 0.001 and r = 0.75, P < 0.0025, respectively). In 169 consecutive patients, DTPA aerosol images performed immediately following perfusion (inhalation scan I) were compared to those carried out on the next day (inhalation scan II) with respect to image quality and assessment of perfusion-ventilation matches or mismatches. Agreement between inhalation scans I and II with respect to perfusion defects matched or mismatched to ventilation was found in 166/169 (98%) studies. The image quality of inhalation scan I was equal to that of scan II in 72%; inhalation scan I was superior in 11% of cases, while scan II was superior in 17%. This submicronic 99mTc-labelled DTPA aerosol is well suited for fast same-day post-perfusion ventilation imaging in patients with clinical suspicion of pulmonary embolism.

Aerosols↗