Flow Behavior of Co-Processed Excipients Using Lactose and Microcrystalline Cellulose as Bulk Fillers

Powder flow is a constant concern in the production of solid dosage forms. Its concise and reliable determination and improvement are challenges for the pharmaceutical industry. Lactose (Lac) and microcrystalline cellulose (MCC) are both widely used pharmaceutical fillers either alone or mixed. In this study, flow determination was performed through methods described on the European Pharmacopoeia. The results obtained showed poor flow and cohesive behavior for Lac and MCC powders and their mixtures (co-processed excipients). The 50% Lac_MCC mixture, with colloidal silicon dioxide (CSD) as the glidant in different proportions, showed relevant improvements in flow. In addition, the effective angle of wall friction (φx), the effective angle of internal friction (φe), arching, and ratholing were also determined, demonstrating the flow behavior in the discharge equipment. Outlet diameters that prevent blockages or insufficient powder flow were also determined. With this study, it was concluded that it was possible to prepare a co-processed excipient with optimal flow behavior composed of Lac_MCC and CSD as a glidant.