Effect of Materials of Construction of Pharmaceutical Processing Equipment and Drug Delivery Devices on the Triboelectrification of Size-fractionated Lactose

Abstract

Triboelectrification of pharmaceutical powder systems during various processing operations may give rise to adhesion and cohesion effects. The aim of this work was to investigate the electrostatic charging of size-fractionated lactose after contact with materials used in pharmaceutical processing and manufacturing operations. Triboelectrfication of fractionated lactose samples was effected through transport at a known gas velocity to make contact with the surface of a cyclone separator constructed from materials typically used for the manufacture of pharmaceutical processing equipment and drug delivery devices. Generally, for all contact surfaces, the magnitude of charge on the lactose samples increased with decreasing particle size, over the range 90–1000 μm, and increasing gas velocity. The charge was electronegative for stainless steel and acetal but electropositive for PVC and polypropylene. The results indicate that a triboelectric series could be proposed by ranking materials in order of increasing work function (i.e. stainless steel, acetal, lactose, polypropylene and PVC). The results show the dependence of electrostatic charge on particle size and type of contact material, which has important implications for pharmaceutical processing and drug delivery.