(303h) Mitigation of Tribocharging in Pharmaceutical Powders Using Surface Modified V-Blenders

The pharmaceutical industry involves handling of powders on a large scale for manufacturing of solid dosage forms such as tablets and capsules constituting about 85% of the total dosage forms. During this manufacturing process, powders get electrostatically charged due to numerous particle-particle and particle-equipment wall collisions and that could lead to compromised powder flow and powder uniformity. In this study, a surface modified blender has been used to analyze tribocharging in pharmaceutical powders. The blender has been fabricated using two types of materials, an insulator, and a conductor. The conductor or the metal arm induces charge of opposite polarity to that of the charge induced by the insulator arm and the overall charge on the powder decreases during the tumbling motion of the blender. In addition to that, a DEM numerical model has been developed using Altair EDEM to provide a mechanistic understanding of tribocharging in pharmaceutical powders using different types of V blenders including surface modified V blender.

Methods:

In this research, Ibuprofen was used as the model drug and processed in aluminum, polyvinyl chloride (PVC), stainless steel, surface modified aluminum-PVC (Al-PVC) and surface modified stainless steel- PVC (SS-PVC) blender at 20% RH for different time intervals such as 2, 10, 20, 30 and 40 mins till charge saturation is achieved. After completion of the blending process, the powder is collected directly in a faraday cup connected to a NanoCoulomb Meter to measure the charge (nC). Each experiment was repeated thrice. For the simulations, the V blender geometry was designed using SolidWorks and DEM model was developed using commercial software Altair EDEM.

Results:

50g of ibuprofen was loaded into the V blender which was then rotated at 13 rpm for different time intervals such as 2, 10, 20, 30 and 40 mins at 13 rpm. The charge saturation was observed at 30 minutes and no significant variation in charge was noted after that and therefore considered as the charge saturation point. In addition to that, it was observed that using blender made of metal, negative polarity charge (Fig 1&4) was observed whereas positive polarity charge was observed using insulator blender (Fig 2). The lowest charge magnitude was observed using surface modified blenders and the polarity of charge was negative (Fig 3&5). Similar observations were made from the DEM simulations.

Conclusion:

We have demonstrated that tribocharging could be significantly decreased by using surface modified blenders in comparison to insulator or metal only blenders. Moreover, it was established that careful selection of equipment materials could significantly reduce the electrostatic charging of powders.