Puffs Of Aerosol Research Articles

Stimulus mediation, specificity and impact of menthol in rats trained to discriminate puffs of nicotine e-cigarette aerosol from nicotine-free aerosol.

It is unclear if e-cigarettes have reduced abuse liability relative to traditional cigarettes, especially when considering advanced devices which deliver nicotine more efficiently. Translatable and predictive animal models are needed to addresses this question. Our goal was to explore the subjective stimulus effects of e-cigarettes by training rats to discriminate puffs of nicotine aerosol from vehicle aerosol using an aerosol delivery system designed to model e-cigarette use patterns in humans. Rats were trained to discriminate between ten, 10s puffs of aerosol generated from 3mg/ml nicotine e-liquid and nicotine-free e-liquid using a food-reinforced operant procedure. Following acquisition, tests were conducted to determine the specificity of the nicotine aerosol stimulus as well as the impact to the stimulus effects of nicotine resulting from the addition of menthol to e-liquid. Rats learned the nicotine aerosol puff vs vehicle puff discrimination in a mean of 25 training sessions. Injected nicotine fully substituted for the stimulus effects of nicotine aerosol. The stimulus effects of nicotine aerosol were blocked by the nicotinic receptor antagonist mecamylamine. The nicotinic receptor partial agonist, varenicline as well as the stimulant d-amphetamine substituted more robustly for nicotine aerosol puffs than did the NMDA antagonist, ketamine. Menthol enhanced the stimulus effects of nicotine aerosol without altering nicotine blood plasma levels. Nicotine aerosol puffs can function as a training stimulus in rats. The stimulus effects were CNS-mediated and receptor specific. Menthol appears to enhance the stimulus effects of nicotine aerosol through a pharmacodynamic rather than pharmacokinetic mechanism.

Technologies for laboratory generation of dust from geological materials

Dusts generated in the laboratory from soils and sediments are used to evaluate the emission intensities, composition, and environmental and health impacts of mineral aerosols. Laboratory dust generation is also utilized in other disciplines including process control and occupational hygiene in manufacturing, inhalation toxicology, environmental health and epidemiology, and pharmaceutics. Many widely available and/or easily obtainable laboratory or commercial appliances can be used to generate mineral aerosols, and several distinct classes of dust generators (fluidization devices, dustfall chambers, rotating drums/tubes) are used for geological particulate studies. Dozens of different devices designed to create dust from soils and sediments under controlled laboratory conditions are documented and described in this paper. When choosing a specific instrument, investigators must consider some important caveats: different classes of dust generators characterize different properties (complete collection of a small puff of aerosol versus sampling of a representative portion of a large aerosol cloud) and physical processes (resuspension of deposited dust versus in situ production of dust). The quantity "dustiness" has been used in industrial and environmental health research; though it has been quantified in different ways by different investigators, it should also be applicable to studies of geological aerosol production. Using standardized dust-production devices and definitions of dustiness will improve comparisons between laboratories and instruments: lessons learned from other disciplines can be used to improve laboratory research on the generation of atmospheric dusts from geological sources.

Evaluation of Inhalation Aids of Metered Dose Inhalers in Asthmatic Children

Many patients have incorrect aerosol inhalation technique with metered dose inhalers (MDI). Several inhalation aids have been developed and marketed for these patients. Even those who have correct inhalation technique may benefit from these devices. We compared bronchodilator efficacy of two puffs of albuterol aerosol administered either directly from a MDI mouthpiece, or from an inhalation aid (InspirEase, Aerochamber, Aerosol Bag) in 20 children who had previously demonstrated proper inhalation technique. The children received two puffs of aerosol from a MDI in each of two modalities tested each day on four different days (double blind). One modality contained albuterol aerosol and the other placebo. Pulmonary function was tested before and at 15, 30, 60, 120, and 180 minutes after treatment. Forced expiratory volume in 1 second (FEV1) increased similarly after all four modes of administration. Six patients who had incorrect inhalation technique benefited from the three inhalation aids. The aerosol bag and InspirEase produced slightly greater bronchodilator response than the Aerochamber. The inhalation aids are useful devices for those who have incorrect inhalation technique, but those who have correct technique do not derive any benefit from these devices.

Direct-writing recorder of the frequency dependence of dynamic compliance analyzed from one cycle of breathing and pulmonary resistance: effect of fenoterol on asthmatic subjects.

We developed a new method of direct-writing recording of the frequency dependence of dynamic compliance analysed from one cycle of breathing and pulmonary resistance. Both pulmonary resistance (RL) and frequency dependence of dynamic compliance (Cdyn.f) are calculated by Fourier-series analysis of flow and transpulmonary pressure in a single cycle of breathing. RL was obtained from fundamental harmonics. Cdyn.f was calculated from 1st and 2nd harmonics and estimated by the ratio of Cdyn at 0.5 Hz to Cdyn at zero frequency, C0.5/C0. We used fenoterol aerosol which contained 0.2 mg of fenoterol with one puff of aerosol. Two puffs of fenoterol aerosol were used in each subject and followed changes of RL, C0 and C0.5 as long as 30 min. After fenoterol inhalation RL decreased considerably and C0.5/C0 cont [C0.5/(control C0)] increased. With time, while RL was kept stable, C0.5/C0 cont increased further. We suggest that fenoterol has a potent effect on the small airways which is enhanced with time.

Exercise-Induced Asthma (EIA): Its Prevention with the Combined Use of Ipratropium Bromide and Fenoterol

Until now very few studies have been performed on the prevention of exercise-induced asthma (EIA) in children with ipratropium bromide + fenoterol. This is why we decided to study 30 children aged between 6 and 15 years, whose EIA was confirmed by a test including a 6-min free race on day 1 of the study. The criterion was a decrease of more than 20% of the basal values of forced expiratory volume in 1 s (FEV1) or FMF. Children whose FEV1 or FMF baseline values were under 60% of those expected according to Polgard tables were excluded. Three tests were performed, the first to determine EIA, the second was performed 72 h later after inhalation of placebo. 72 h after day 2 the patients returned in order to repeat the test, but this time, aerosol therapy with the combination ipratropium + fenoterol was applied prior to the race. The dosage of the combination was 1 puff of aerosol per 10 kg body weight, up to a maximum of 4 puffs. Each puff of the combination contains 0.02 mg of ipratropium bromide and 0.05 mg fenoterol. Functional assessment of children was carried out by means of forced spirometry. There were no significant differences between the placebo group and the group which received no medication, but there was a significant difference between the treated group and the other two, not only in the FEV1 and FMF values but also in forced vital capacity TEST.(ABSTRACT TRUNCATED AT 250 WORDS)

1785 EVALUATION OF INHALATION AIDS OF METERED DOSE INHALERS IN ASTHMATIC CHILDREN

Many patients have incorrect aerosol inhalation technique with metered dose inhalers (MDI) and fail to benefit fully from this form of therapy. Several inhalation aids have been developed and marketed recently for those cases. However such aids may benefit even those with proper technique. We compared bronchodilator efficacy of 2 puffs of albuterol aerosol administered either directly from a MDI or from an Inspirease (Key Pharm, Miami, Fla), an Aerochamber (Monaghan, Plattsburgh, NY), or our own Aerosol Bag (Pediatrics 1984) in 20 patients with stable asthma aged 8-15. All had been instructed in inhalation technique in the past and were receiving beta agonists from MDI. They were taught the use of the 3 inhalation aids and were studied with a double blind, randomized cross-over protocol in 4 days. After the baseline pulmonary function was tested the patient inhaled 2 puffs of aerosol from each of two of 4 modalities each day. One contained albuterol and the other placebo. The patient inhaled from a MDI unsupervised but was supervised by the examiner with the 3 inhalation aids. FEV1 increased similarly after all 4 modes of administration at 15, 30, 60, 120 and 180 minutes (maximum increases at 60 minutes were 33, 33, 34, 39% over the baseline for MDI, Inspirease, Aerochamber and aerosol bag). Six patients who had suboptimal inhalation technique benefitted from 3 aids equally. Those with proper technique did not benefit from any of the inhalation aids. The 3 new inhalation aids are helpful to those with difficulties in using MDI.

Improvement of pressurised aerosol deposition with Nebuhaler spacer device.

The effect on aerosol deposition from a pressurised metered dose inhaler of a 750 cm3 spacer device with a one way inhalation valve (Nebuhaler, Astra Pharmaceuticals) was assessed by means of an in vivo radiotracer technique. Nine patients with obstructive lung disease took part in the study. The pattern of deposition associated with use of a metered dose inhaler alone was compared with that achieved with the spacer used both for inhalation of single puffs of aerosol and for inhalation of four puffs actuated in rapid succession and then inhaled simultaneously. On each occasion there was a delay of 1 s between aerosol release and inhalation, simulating poor inhaler technique. With the metered dose inhaler alone, a mean (SEM) 8.7 (1.8)% of the dose reached the lungs and 80.9 (1.9)% was deposited in the oropharynx. With single puffs from the spacer 20.9 (1.6)% of the dose (p less than 0.01) reached the lungs, only 16.5 (2.3)% (p less than 0.01) was deposited in the oropharynx, and 55.8 (3.1)% was retained within the spacer itself. With four puffs from the spacer 15.2 (1.5)% reached the lungs (p = 0.02 compared with the metered dose inhaler alone, p less than 0.01 compared with single puffs from the spacer), 11.4 (1.2)% was deposited in the oropharynx, and 67.5 (1.8)% in the device itself. It is concluded that the spacer device gives lung deposition of metered dose aerosols comparable to or greater than a correctly used inhaler and oropharyngeal deposition is greatly reduced. The spacer should be used preferably for the inhalation of single puffs of aerosol but may also be used for the inhalation of up to four puffs actuated in rapid succession and then inhaled simultaneously.