Monitoring Magnesium Stearate Blending in a V-Blender Through Passive Vibration Measurements

Process analytical technologies are implemented within the pharmaceutical manufacturing process to rectify issues associated with current sampling methods. These include inline monitoring methods such as passive vibration measurements which are non-intrusive and less costly to other methods. In the final mixing stage of the tablet manufacturing process, a lubricant is added to ensure the mixture is ejected from the tablet die cleanly. To monitor this process, an accelerometer was attached to the lid of the V-blender loaded with various particles and magnesium stearate. At a fixed fill level, the lubricant concentration and particle mass were varied to investigate the effects of changes in process parameters on the signal vibrations measured by the sensor, the coefficient of restitution, and the flowability. It was found that measured vibrations from stress waves propagated upon collisions of the particles with the V-shell respond to and can distinguish differences in particles. As well, the magnesium stearate layer around particles alters energy dissipation and subsequently the measured vibrations. A mixing endpoint of uniform distribution of magnesium stearate with primary particles can be identified from vibrations measured by an accelerometer attached to the lid of the V-blender. The flowability change was considered negligible in the particles due to their physical morphology. These findings indicate that passive vibration measurements can be a viable, non-intrusive monitoring method while providing insight into V-blender mixing behaviors as well as improving process efficiency.