Power consumption measurement and temperature recording during granulation.

This study was performed to elucidate the influences of process and formulation design using power consumption and temperature measurements during granulation. Power consumption was recorded "in process" using a previously introduced computer program for optimal end-point detection at an early stage. The temperature increase (DeltaT) during granulation was recorded using a temperature sensor. The temperature increase in the wet powder bed expresses the friction forces at interparticle contacts occurring during granulation. The maxima of temperature profile occurred at 130% saturation, whereas the maxima of power consumption were determined at 100% saturation. The ratio of temperature and power consumption (TPR factor) is introduced as a signature of formulation design. TPR factor was found to be dependent on particle size, particle surface, water absorption capacity and solubility of the excipient and model drug, respectively. However, TPR factor was found to be independent of process design, such as the filling level of the mixer. Understanding and controlling the granulation process is a key factor in robust dosage form design. The "in process" control fits ideally the prerequisites of a drug quality system for the 21st century and FDA's Process Analytical Technology (PAT) initiative. The results of previous and present works of our research group will be used in a following step to develop an artificial neural network for granulation "in process" control.