(29e) The Effect of Surface Modification On the Triboelectric Characteristics of Pharmaceutical Powders

Powder handling processes involve contact of particles with each other and the surface of the transporting vessel, which normally lead to electrostatic charging of the particles. In many cases the electrostatic charging will affect the behavior of the powder during the handling process. This study is to understand the triboelectric characteristics of surface modified as compared to original untreated pharmaceutical active ingredient (API) powders. The triboelectric charging effect was quantified at different relative humidities (RH) and different surface coating levels; using stainless steel and polycarbonate as the contact surfaces. The results show that for untreated powders, the particles charge less at lower RH and charge more at high RH; while for the surface modified powders, the opposite is true. BET surface area measurement was used to determine the specific surface area of the particles, which is then used to calculate the charge density. Inverse Gas Chromatography (IGC) is used to determine the electron acceptor-donor characteristics and correlated with ones obtained from the triboelectric experiment for the unmodified and modified particles. Meanwhile, flow characterization results of these powders show a significant improvement in flow behavior that accompanies decrease of triboelectric charging for the surface modified powders.