Characterising the surface adhesive behavior of tablet tooling components by atomic force microscopy

Purpose: The aim of this study is to develop an atomic force microscopy (AFM) based approach to study the adhesive forces between tabletting punches and model formulation ingredients, that can ultimately be used to understand and predict issues such as sticking during tabletting compression.Methods: Adhesive interactions were studied between single lactose particles and coated tablet punches. The adhesion was measured at varying relative humidities (RHs) and the influence of surface roughness was investigated. Roughness parameters were measured with AFM imaging and a modeling approach used to predict the influence of roughness on adhesion.Results: Surface roughness was found to play a significant role in the observed lactose-punch adhesion and the variation of this adhesion across the punch surface. Such differences between punches can be correlated to observations from industrial use. Adhesion forces were spatially mapped to indentify “hot spots” of high adhesion. A modeling approach can predict the rela...