Biomedical and General Engineering Department

Degree Name

BS in Biomedical Engineering




Kristen Cardinal


Within pharmaceutical manufacturing, size reduction is one of the most extensively used and vital unit operations. Size reduction in tablet production is achieved primarily through milling procedures, which allows for attaining product uniformity, optimizing product solubility, and improving bioavailability. Additionally, powders with a narrow range of size distribution can obviate problems in downstream processing as pertains to blending, compression, and coating as well as improve drug performance1. The purpose this study was to characterize the effect of various size reduction parameters as a result of the pharmaceutical milling process on a lactose wet granulation formulation and chemically active extruded lentils. Variations in sizing as a result of milling conditions were assessed using samples of extrudated lentils (extrudate) and lactose granules. Lactose granules and extrudate were milled and compared using the L1A Fitz mill based on blade orientation, mill speed, and screen size. Additionally, the 197 Comil was evaluated as a potential substitute for extrudate milling by comparing resulting PSD, morphology, and angle of repose using extrudate milled on both the 197 Comil and L1A Fitz mil. For lactose granules, data showed that fine particle sizing occurred at 9000 RPM, while only larger particles were reduced at 1000 RPM, 4000 RPM, and 6600 RPM. Large particles were reduced much more effectively as speed increased from 1000 RPM to 4000 RPM, however less change was seen from 4000 RPM and 6600 RPM. For both extrudate and granules, particle size decreased as mill speed was increased and smaller screens were utilized. Resulting data for milled extrudate provides support for obtaining analogous particle properties between the two mill types. Because of a lack of direct correlation between milling conditions on the Comil and Fitz Mill, processes should be developed independently in order to achieve desired properties.