A novel approach to determine solid fraction using a laser-based direct volume measurement device

Material properties play a significant role in pharmaceutical processing. In the present study, a novel approach is used to determine solid fraction (SF) based on a direct measurement (DM) of the apparent volume of a sample. The sample was scanned with low intensity laser beams that integrate the sample thickness across the surface (area) and quantitate the apparent volume. The SF by DM method was compared against that obtained by volume displacement (VD) and manual measurement methods. SF was determined by all three methods for formulations of Avicel DG, lactose and a 1:1 mixture of the two. The results from DM method and variability were comparable to that obtained by VD method. The manual method provided lower and more variable results. The DM method was able to differentiate between SF of different ribbon and tablet formulations and at varying force levels. Tracking SF of compacts during tablet development can help in setting acceptable specifications and to understand material deformation behavior during compression. Further, the results of the study indicate that the DM method using laser scan technique was suitable for routine testing of SF of roller compacted ribbons and compressed tablets.