3D characterisation of dry powder inhaler formulations

P. Gajjar, I.D. Styliari, T.T.H. Nguyen, J. Carr, X. Chen, J.A. Elliott, R.B. Hammond, T.L. Burnett, K. Roberts, P.J. Withers, D.Murnane - Henry Moseley X-ray Imaging Facility, Department of Materials, School of Natural Sciences, The University of Manchester, UK ; School of Life and Medical Sciences, University of Hertfordshire, UK ; Centre for the Digital Design of Drug Products, School of Chemical and Process Engineering, University of Leeds, UK ; Department of Materials Science & Metallurgy, Cambridge, UK ; Henry Royce Institute for Advanced Materials, Manchester, UK

Carrier-based dry powder inhaler (DPI) formulations need to be accurately characterised for their particle size distributions, surface roughnesses, fines contents and flow properties. Understanding the micro-structure of the powder formulation is crucial, yet current characterisation methods give incomplete information. Commonly used techniques like laser diffraction (LD) and optical microscopy (OM) are limited due to the assumption of sphericity and can give variable results depending on particle orientation and dispersion. The aim of this work was to develop new three dimensional (3D) powder analytical techniques using X-ray computed tomography (XCT) that could be employed for non-destructive metrology of inhaled formulations.