Roller compaction: Ribbon splitting and sticking

Publication date: Available online 22 January 2019Source: International Journal of PharmaceuticsAuthor(s): Osama Mahmah, M.J. Adams, Chalak S.Omar, Bindhu Gururajan, Agba D. SalmanAbstractRoller compaction is the main technique employed in dry granulation. Ribbon sticking and splitting are among the major factors that can hinder the use of this process for some formulations. Ribbon splitting can occur either transversally (through the ribbon thickness) or longitudinally (through the ribbon width). It was observed that transverse splitting is commonly associated with sticking of the split ribbons to the rollers and results in an inferior performance of the process. Longitudinal splitting is associated with an across-width distribution of the ribbon density so that there may an adverse effect on the mechanical strength and dissolution properties of the tablets formed from the milled granules. The aim of the current work was to elucidate the mechanisms of splitting by an experimental study involving single component powders with a range of yield strengths, including those that are commonly used as excipients. Both smooth and knurled rollers were employed without and with lubrication by applying magnesium stearate to the rollers. The minimum gap was fixed and the maximum roll stress was varied. The observed trends for the smooth rollers were rationalised in terms of a splitting index, which is a measure of the residual stresses driving crack growth relative to the tensile strengt...
Source: International Journal of Pharmaceutics - Category: Drugs & Pharmacology Source Type: research