Effect of amount and composition of granulation liquid on mixing, extrusion and spheronization

Abstract Avicel RC 581 is regarded as an excellent excipient in formulations for extrusion (1). The CMC-Na in this microcrystalline cellulose improves the binding properties and the plasticity. In this study Avicel RC 581 was mixed in various ratios with theophylline. These mixtures were granulated with either water or water/ethanol (60/40) mixtures in a Collette high shear mixer. The power consumption during mixing was recorded as a function of the amount of granulation liquid. From the mixtures obtained in this way the plasticity / viscosity was determined before extrusion. Measurement of the plasticity / viscosity was carried out in an apparatus similar to the one described by Alleva et a1 (2). Extrusion was done using a Fuji Paudal extruder (EXD-60); the power consumption during extrusion was recorded. The influence of the amount and composition of the granulation liquid on the various power consumptions and on plasticity / viscosity will be discussed, as well as the spheronization behaviour of the extruded pellets.