1: Eur J Pharm Biopharm. 2008 Nov;70(3):839-44. Epub 2008 Jun 24.

Optimization of the aerosolization properties of an inhalation dry powder based
on selection of excipients.

Minne A, Boireau H, Horta MJ, Vanbever R.

Department of Pharmaceutical Technology, Université catholique de Louvain,
Brussels, Belgium.

The aim of this study was to investigate the influence of formulation excipients 
on physical characteristics of inhalation dry powders prepared by spray-drying.
The excipients used were a series of amino acids (glycine, alanine, leucine,
isoleucine), trehalose and dipalmitoylphosphatidylcholine (DPPC). The particle
diameter and the powder density were assessed by laser diffraction and tap
density measurements, respectively. The aerosol behaviour of the powders was
studied in a Multi-Stage Liquid Impinger. The nature and the relative proportion 
of the excipients affected the aerosol performance of the powders, mainly by
altering powder tap density and degree of particle aggregation. The
alanine/trehalose/DPPC (30/10/60 w/w/w) formulation showed optimal aerodynamic
behaviour with a mass median aerodynamic diameter of 4.7 microm, an emitted dose 
of 94% and a fine particle fraction of 54% at an airflow rate of 100 L/min using 
a Spinhaler inhaler device. The powder had a tap density of 0.10 g/cm(3). The
particles were spherical with a granular surface and had a 4 microm volume median
diameter. In conclusion, optimization of the aerosolization properties of
inhalation dry powders could be achieved by appropriately selecting the
composition of the particles.


PMID: 18620052 [PubMed - indexed for MEDLINE]

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