Issa Munu^ab, Kendal Pitt^b, Christopher Window-Yule^a, Andrew Ingram^a 

^a School of Chemical Engineering, University of Birmingham, Edgbaston, B15 2TT 

^b GSK Global Supply Chain, Priory Street, Ware, SG12 0DJ 

This study presents an opportunity of predicting granule and tablet properties through torque measurement of the granulation bowl and the force exerted on a probe within the powder bed. Acetaminophen was high shear wet granulated with D-mannitol, microcrystalline cellulose, sodium starch glycolate, povidone and water as the binding liquid. Torque and Lenterra force in-line measurements monitors the granulation process in real time and shows how the entire process evolve during the dry mixing, water addition and wet massing phases. Granules produced were characterised by basic flowability energy, specific energy, compressibility, and permeability using Freeman rheometer technology (FT4) and by particles size using QicPic gravity dispersing system (GRADIS). In addition, tablets were generated using a Gamlen press characterising tablets by compressibility, tabletability and compactibility which are dependent on tablets compaction pressure, tensile strength, and solid fraction.  

The results showed that the torque and Lenterra force in-line measurements are providing unique rich information about the granulation process. The Lenterra probe is more sensitive during the water addition phase. The cumulative torque during water addition has a strong contribution on the bulk granule compressibility and permeability. In addition, the cumulative force during water addition phase has a strong contribution on granules specific energy, basic flowability energy and tablet tensile strength. Model developed using evolutionary discovery equation shows that the force during water addition and tablet compression force are key parameters in predicting tablet tensile strength.  

In conclusion measurements by the Lenterra force probe can be used to predict tablet tensile strength which will minimise material waste and improve performance of tablet compression operators.