Amino acid-modified spray-dried powders with enhanced aerosolisation properties for pulmonary drug delivery - Spray Drying

Amino acid-modified spray-dried powders with enhanced aerosolisation properties for pulmonary drug delivery
Received 10 November 2006; revised 20 February 2007; accepted 30 March 2007. Available online 9 April 2007
P.C. Sevillea, , , T.P. Learoyda, H.-Y. Lib, I.J. Williamsonc and J.C. Birchallb
Powder Technology
Article in Press
ScienceDirect
Copyright ? 2007 Elsevier B.V. All rights reserved.
aInhalation Technology Research Team, School of Life and Health Sciences, Aston University, Birmingham B4 7ET, UK
bGene Delivery Research Group, Welsh School of Pharmacy, Cardiff University, Cardiff CF10 3XF, UK
cNewport Chest Clinic, Gwent Healthcare NHS Trust, Newport NP20 4GA, UK
Abstract
In this study, the amino acids arginine, aspartic acid, leucine, phenylalanine and threonine were investigated as ?dispersibility enhancers? in spray-dried powders for inhalation. Parameters such as spray-dried yield, tapped density, and Carr's Index were not predictive of aerosolisation performance. In addition, whilst the majority of amino acid-modified powders displayed suitable particle size distribution for pulmonary administration and potentially favourable low moisture content, in vitro particle deposition was only enhanced for the leucine-modified powder. In summary, leucine can be used to enhance the dispersibility and aerosolisation properties of spray-dried powders for pulmonary drug delivery.
Graphical abstract
The potential for amino acids to modify the aerosolisation characteristics of spray-dried powders was investigated. Five amino acids (arginine, aspartic acid, leucine, phenylalanine and threonine) were incorporated into the spray-drying formulation at four different concentrations (0?20% w/w). Leucine-modified powders demonstrated the highest in vitro fine particle fractions (up to 78% of capsule contents), suggesting that leucine is an effective aerosolisation enhancer.
Keywords: Spray-drying; Salbutamol sulphate; Amino acids; Dispersibility; Pulmonary deposition
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