Efecto del método de fabricación sobre las características de flujo de mezclas de celulosa microcristalina y carbonato de calcio

The purpose of this study was to investigate the effect of the fabrication method on the flow characteristics of mixtures of microcrystalline cellulose (MC) and calcium carbonate (CC), in order to improve the properties of a direct compression excipient, microcrystalline cellulose. Physical mixtures with and without polyvinylpyrrolidone (PVP) were prepared, as well as mixtures granulated with a PVP solution, by spray drying and wet kneading. The flow rate and the compressibility index of the mixtures were measured. The results show, by physical mixtures as well as by spray-dried granules, a biphasic linear behavior with higher powder flow by predominant CC concentrations in the mixtures. The powders flow in the following order: Physical mixtures < Physical mixtures with PVP < Spray-dried mixtures. The measurements obtained by the two different methods show, in some cases, contradictory results against the experience that higher powder compressibility corresponds to lesser powder flow. Both methods show limitations because of a lack of precision. Fabrication of the mixtures by spray drying, at CC concentrations ≥ 60%, produces the higher powder flow.