Modulation of the tabletting behaviour of microcrystalline cellulose pellets by the incorporation of polyethylene glycol

This study investigated the effect of incorporating a soft material (polyet hylene glycol; PEG) into pellets of microcrystalline cellulose (MCC) on the compression behaviour and compactability of the pellets. Low and high poro sity MCC pellets were formed. Pellets were also formed from a 1:1 (w/w) mix ture of MCC and PEG 6000 to have a porosity equal to that of the low porosi ty MCC pellets. The degree of compression of the pellets and the porosity, permeability to air and tensile strength of the resulting tablets were dete rmined. Some of the tablets were also deaggregated, and the thickness and p orosity of the retrieved pellets were determined. The lowest total tablet p orosity was seen with tablets made from pellets containing PEG. The intergr anular porosity and the permeability of these tablets were similar to those of tablets made of the high porosity MCC pellets. However, the thickness a nd porosity of retrieved MCC/PEG pellets were similar to those of the low p orosity MCC pellets. The degree of compression levelled off at a lower pres sure for the MCC/PEG pellets than for the MCC pellets.Tablet strength value s for the MCC/PEG pellets was intermediate between the MCC pellet types and not greatly affected by the applied pressure. It was concluded that the de formation propensity of the pellets was, in general terms, increased due to the presence of the soft material. However, the character of the deformati on behaviour changed towards an increased tendency for local deformation du ring compression, i.e., the ability of adjacent pellet surfaces to conform to each other increased, without marked changes in the main dimensions and porosity of the pellets. (C) 1999 Elsevier Science B.V. All rights reserved .