| Pharmaceutical formulations consist of homogeneous mixtures of ingredients that provide the desired characteristics of the final product. The purpose of this research was to develop an in line system for monitoring pharmaceutical blend uniformity. This system will measure the degree of blend uniformity and segregation when pharmaceutical powders flow. An interface was developed to monitor the flowing powder blend at the outlet of the blender or hopper and before the powder enters the compressing machine. This interface was designed to allow the installation of a fiber optic probe to monitor the flowing dynamic powder and collect spectra during the emptying of the blender with near infrared spectroscopy (NIRS) using the diffuse reflectance mode.; The spectra were collected with a NIR diode array spectrometer, and the free fall spectra was obtained using a CDI 256 element T.E cooled InGaAs array. The system included a fiber optic probe cable equipped with collimating lens, and a dual tungsten halogen light source with gold diffuse reflector. The system is operated with a software called Spec 32. The integration time used to collect spectra was 5 ms, and a total of 32 spectra were averaged.; Near Infrared Spectroscopy was used because it offers fast spectral acquisition and it is a non-destructive technique that does not require sample preparation. Chemometric software was used to analyze the spectra acquired using preprocessing techniques such as Multiplicative Scatter Correction (MSC), Standard Normal Variate (SNV) and Second Derivative, to remove or reduce irrelevant source of variation, and using Principal Component Analysis (PCA), to represent the variation present in many variables using a small number of "factors". |
