Particle size coarsening induced by valve silicone in a metered dose inhaler.

The objective of this study was to evaluate the effect of valve silicone on the delivered particle size distribution of a suspension metered dose inhaler (MDI). Valves were manufactured with distinct levels of silicone, which could be differentiated with Fourier transform infrared spectroscopy (FT-IR). The amount of silicone in the valve was proportional to the amount of silicone that entered the formulation and the subsequent decrease in fine particle fraction (FPF) of the active pharmaceutical ingredient (API) measured by Andersen cascade impaction.

Validity of in vitro tests on aqueous spray pumps as surrogates for nasal deposition.

Purpose: To determine whether deposition pattern is related to in vitro measurements of droplet size, plume geometry, and spray pattern between two different nasal spray pumps believed to have different performance characteristics.

Methods: Ten healthy volunteers inhaled radiolabeled saline from two different spray pumps (pump A and pump B). Deposition pattern was quantified from lateral views of the nose by gamma scintigraphy, expressed as the ratio of anterior to posterior (I:O) and superior to inferior (U:L) deposition.

[Peripheral airway obstruction in the course of occupational exposure to asbestos].

Typically, the functional abnormalities in individuals exposed to asbestos dust take the form of a pulmonary fibrosis. Recently, several authors have stressed the early existence of small airways obstruction. In the present study, by measurement of closing volume, we have confirmed an obstructive factor in a certain number of exposed subjects, even if they were non-smokers, i.

[Determination of the closing volume and its value in the early detection of chronic obstructive lung disease].

The determination of the closing volume appears as a good test for the early detection of obstructive lung diseases and of disorders in the ventilation distribution. Easy to perform, its use should become extensive. To make use of this investigation under the better possible conditions, it is strictly necessary to respect methodologic norms and an excellent technology and to be aware of some morphologic anomalies in the curves.

A study of pulmonary dust deposits using the electron microscope in conjunction with the electron sound analyser.

Castaing's electronic microsound method has been used to locate mineral particles in lung tissue. Silicon and other minerals were found in the interstitial elastic-type fibres in the lungs of patients with pulmonary fibrosis.