Process control and end-point determination of a fluid bed granulation by application of near infra-red spectroscopy

In the pharmaceutical industry, fluid bed granulation processes require tight control to ensure reliability. This is particularly the case when the product characteristics add to make the process intrinsically non-robust. Tight process control is generally achieved by careful and accurate control and monitoring of the process parameters affecting the granule wetting/drying equilibrium. However, these parameters are prone to natural unavoidable variation, causing variable and difficult to determine granulation end-points. Obtaining an immediate measure of a critical product characteristic during processing could help by leading to further improvements in process reliability. The application of in-line near infra-red spectroscopy (NIRS) to obtain granule moisture content and particle size change data is described. The technique is capable of monitoring the fluid bed process in 'real time', allowing modification of process conditions if required and end-point identification. This should lead to more optimum product characteristics and greater process reliability. (C) 1997 Elsevier Science B.V.