The Effect of Lung Function and Mode of Inhalation on Penetration of Aerosol into the Human Lung

Abstract

. Effect of lung function and mode of inhalation on penetration of aerosol into the human lung. The method using radioactive tracer particles has been applied to study the effect of the mode of inhalation of aerosols on the depth of deposition in the lungs of 50 patients with airways obstruction. The findings show that the penetration of particles is directly related to: (1) volume inspired per breath (VI); (2) forced expiratory volume in one second (FEVY); and inversely related to (3) flow rate during inhalation (V). In mathematical terms, alveolar deposition (%)= 40 3 (VI)+ 10-98 (FEV1)-0 75 (V)+40 4; for this regression F=4-41 and P<001.Topical administration of drugs into the bronchial tree by inhalation of aerosol often has advantages over the oral and parenteral routes, particularly in patients with reversible airways obstruction. The dose is relatively small (Lal et al., 1972) and response may be more rapid (Plit et al., 1972). The main benefit of this route, however, is that high levels of the drug are concentrated at the site of action in the lung, giving the desired therapeutic action while minimising undesired systemic side effects.The efficacy of topical therapy depends on the proportion of the inhaled drug which is deposited in the lung (Blackwell et al., 1974) and, for certain drugs, that proportion that is retained in the more peripheral parts (Godfrey et al., 1974). Some of the factors which determine penetrance of aerosol have long been known to particle physicists (Hatch and Gross, 1964 MethodThe tracer technique used here to assess depth of deposition and clearance of inhaled particles in humans has been fully reported by . Polystyrene particles (5±0 7 um) were generated by a spinning disc (May, 1949) and inhaled via the mouth of the patients seated upright. The particles were tagged unleachably (Few et al., 1970) with the gamma-emitting radionuclide teehnetium-99m (99mTc). The volume inspired in a single breath (Vi), 0 1 1, 0 30, 0 50, 0'75 or 0-88 litre, was randomly allocated to each patient and determined by an automatic valve. After inspiration there was an obligatory 3-second breath-holding pause before exhalation. The average flow rate during inhalation was measured by a pneumotachograph. The mean, range, and standard deviation (SD) of the flow rate during inhalation (V) for the 44 patients for whom measurements were available were 25'4 (13 3-50 4; SD±7 9) 1/min. Immediately after inhalation the patients washed out their mouths and then swallowed some water to remove radioaerosol from the oropharynx and oesophagus.Immediately afterwards and six hours later gamma radiation from the patients' lungs was counted by 194

Deposition and clearance of inhaled 18FDG powder in patients with chronic obstructive pulmonary disease

“…RYAN et al [15] reported that aerosols deposit more peripherally during tidal breathing than with a single deep breath. There have been reports that once the aerosol has entered the lungs, deposition by impaction in large bronchi is more likely in patients with COPD, whose airways may be narrowed by a combination of bronchospasm, oedema and mucous hypersecretion [3,4,7], and that the penetration of particles is inversely related to flow rate during inspiration [3]. In the present study, inspiratory flow rate during inhalation tended to be lower in COPD patients than in normals.…”

“…It has been reported that the aerosol deposition within the lung in patients with COPD observed in a rectilinear scan is decreased compared with normal subjects [3,4]. In these studies, subjects inhaled aerosol with tidal breathing [4] or a limited inspiratory volume of <1 L [3].…”

“…In these studies, subjects inhaled aerosol with tidal breathing [4] or a limited inspiratory volume of <1 L [3]. In the present study, subjects inhaled powder from residual volume to total lung capacity.…”

“…Aerosols have been used therapeutically to treat diseased lungs and the deposition of inhaled radioparticles in the lung has been studied by gamma camera in normal subjects with or without bronchoconstriction [2], and in patients with chronic obstructive pulmonary disease (COPD) [3,4] or bronchial asthma [5,6]. The distribution in the central and peripheral lung zones between control and narrowed airways is not consistent.…”

Inhaled chemotherapy in lung cancer: future concept of nanomedicine

“…The inhaled volume is increased and the aerosol penetrates deeply into the lung parenchyma. 103,104 To overcome the problem of actuationinhalation, coordination breath-actuated pressurized MDIs were introduced to the market. 105 Nevertheless, improved peripheral deposition was observed if patients did not hold their breath on completion of inhalation in comparison with pressurized MDIs that are not breath-actuated.…”