Physical, morphological and chemical modification of Al-based nanofillers in by-products of incinerated nanocomposites and related biological outcome.

The number of products containing nanomaterials is increasing this last ten years. Information and literature about the end-of-life of nanocomposites often remains partial and does not address the overall fate and transformations of nanoparticles that may affect biological responses. This paper underlines that the physico-chemical features of nanoparticles can be modified by the incineration process and the available toxicological data on pristine nanofillers might not be relevant to assess the modified nanoparticles included in soot. Combustion tests have been performed at lab-scale using a cone calorimeter modified to collect fumes (particulate matter and gas phase) and have been characterized using various techniques. Nanocomposites selected were poly(ethylene vinyl acetate) containing Al-based nanoparticles, i.e. boehmites or alumina. Evaluations of in vitro cytotoxicity responses on pristine nanofillers, soot and residual ash, show that safe boehmite nanoparticles, become toxic due to a chemical modification after incineration process.

[Bench-test evaluation of spacer devices for fluticasone delivery to infants]. / Chambres d'inhalation pour délivrance de fluticasone chez le nourrisson au banc d'essai.

INTRODUCTION: Use of a spacer device to optimize the delivery of fluticasone to infants with asthma is an important issue and clinicians require guidance around the choice of device. This in vitro study characterizes the particle size and the fluticasone delivery via 9 spacers. METHODS: We used an in vitro infant nasal cast with two different inspiratory flow rates (50 and 100mL/s). Fluticasone particle size in the aerosol was evaluated by laser diffractometry and tracheal deposition by spectrophotometric assay. RESULTS: Significant differences in particle size were observed between the 9 spacers (similar D50 but D90 from 5.65±0.65 to 8.80±1.35µm). A 75 % or higher respirable fraction was obtained for only 5 spacers. The 50mL/s flow rate lead to the best drug delivery. At this flow, OptiChamber® (62±3 %) and Vortex® (91±8.5 %) had a tracheal deposition over 50 % of the initial dose of fluticasone, although the 7 other spacers exhibited a fluticasone deposition less than 25 %. DISCUSSION: This study shows a wide variation of drug delivery between the 9 spacers studied. We demonstrate that a low inspiratory flow and a spacer showing antistatic properties facilitate drug delivery.