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.