Impact of salbutamol sulphate particle properties on the tribocharging of inhalable mixtures

Joana Pinto

Impact of salbutamol sulphate particle properties on the tribocharging of inhalable mixtures

 J T Pinto1,2, S Zellnitz1, E Roblegg1,2, A Paudel1,3

1Research Center Pharmaceutical Engineering GmbH, Inffeldgasse 13, Graz, 8010, Austria

2 Institute of Pharmaceutical Sciences, Pharmaceutical Technology and Biopharmacy, University of Graz,   8010 Graz, Austria

3 Institute for Process and Particle Engineering, Graz University of Technology, Inffeldgasse 13,

Graz, 8010, Austria


Dry powder inhalers (DPIs) are used to administer powder formulations containing active pharmaceutical ingredients (APIs) to the lung. Most commonly these are formulated by mixing the micronized API with larger excipient particles (carrier) in a practice known as adhesive mixing. The success of the formulation is dependent on many factor, in particular on the inter-particle and particle-surface interactions during manufacturing, storage and delivery. Among particle interactions, triboelectrification, can lead to particle agglomeration and adherence to surfaces, detrimentally impacting DPI quality. Thus, the aim of the present work was to understand how distinct salbutamol sulphate (SS) particle characteristics can affect the charging behavior of adhesive mixtures containing mannitol as a model carrier material.

It was demonstrated that SS particles’ properties inherited from distinct micronization processes (spray-drying and jet-milling) can lead to contrasting charging behaviors. Spray-dried SS charged positively and to a lesser extent than its milled counter-part that charged negatively and to a greater degree. After mixing SS adherence to the carrier particles’ surface significantly impacted the charging behavior of mannitol, decreasing its charge density. However, no difference could be found between either the spray-dried or milled SS blends. 

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