EFFECT OF BATCH VARIATION AND SOURCE OF PULP ON THE PROPERTIES OF MICROCRYSTALLINE CELLULOSE

We have investigated the characteristics of three batches of microcrystalline cellulose supplied by the same manufacturer but differing in the manufacturing process employed and/or the type of wood pulp used as raw material. Significant differences were found as regards lignin and hemicellulose contents, percentage crystallinity (calculated from IR spectra and X-ray diffraction data), enthalpies of immersion and capacity for moisture absorption. There were close correlations between crystallinity and the parameters reflecting interaction between microcrystalline cellulose and water. All three varieties had very similar particle size distributions, but the variety obtained from non standard pulp had a significantly greater specific surface due to greater intraparticle porosity. These differences did not significantly affect parameters such as compressibility and mean yield pressure, but are nevertheless potential causes of differences in behaviour in pharmaceutical products.