DRIFT-IR for quantitative characterization of polymorphic composition of sulfathiazole

The quality assurance of the product during the whole development and manufacturing cycle of pharmaceuticals through increased level of process understanding is the main aspect to be considered within process analytical technology (PAT). Therefore, development of new tools using, e.g., multivariate methods for quality control in different steps of manufacturing process are of great importance. In this context, diffuse reflectance fourier transform infrared (DRIFT-IR) spectroscopy together with multivariate statistical process control (MSPC) analysis, soft independent modeling of class analogy (SIMCA), orthogonal signal correction (OSC) preprocessing and partial least squares (PLS) regression methods were applied to polymorphic characterization of crystalline bulk product. X-ray powder diffraction (XRPD) was used as a reference technique. The use of several multivariate techniques in rapid evaluation of purity and polymorphic composition of bulk samples is demonstrated. This offers an additional method for quality monitoring of the bulk product after crystallization process within PAT concept.