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

Abstract

Triboelectri®cation 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.Triboelectri®cation 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 mm, 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.

Does electrostatic charge affect powder aerosolisation?

“…14 Therefore, interactions between particles and different material surfaces may result in different charge levels and polarity in the powder. Eilbeck et al 15 investigated the charging of lactose by blowing the particles through a cyclone apparatus with interchangeable internal surface materials. Polyvinylchloride (PVC) generated positively charged particles whereas acetal and stainless steel produced negative charges.…”

“…Polypropylene imparted minimal charge on the particles and was thus suggested to be a suitable material for avoiding charges during processing. 15 Likewise, Elajnaf et al 16 studied the electrostatic characteristics of salbutamol sulphate and iprotropium bromide, including both drug powders and lactose blends, in three different containers (stainless steel, acetal and polypropylene) and found that the charge was dependent on both the powder and the container surface. On the other hand, Staniforth and Rees 13 purposely employed triboelectrification to facilitate particle adhesion in achieving stable ordered powder mixes.…”

Tribo-electric charging and adhesion of cellulose ethers and their mixtures with flurbiprofen

“…The chemical structure, functional groups, surface chemistry (Kamiyama et al, 1994;Mazumder et al, 2006;Shinohara et al, 1976), particle size, shape, surface roughness (Carter et al, 1998;Eilbeck et al, 1999;Traini et al, 2012) and electrical properties of powders and contacting surfaces (Bailey and Smedley, 1991;Rowley, 2001) can all affect the tribo-electrification process and subsequent particle surface adhesion. Moreover, the charge transfer process is further complicated due to external factors that may influence the charging process including relative humidity, temperature, nature of contacting material and the velocity of particles (Matsusaka et al, 2010).…”

A methodological evaluation and predictive in silico investigation into the multi-functionality of arginine in directly compressed tablets

“…These findings were also discussed by [25]. Although surface roughness is believed to have an effect on the surface charge of the particles, it is envisaged that this effect is minimal in pharmaceutical powders as they have low surface roughness [26] (Eilbeck et al, 1999)…”