Chemometrics approach to the determination of polymorphism of a drug compound by infrared spectroscopy

A chemometrics approach, multivariate calibration in particular, was used t o determine the polymorphism of a drug compound based on Fourier transform infrared (FTIR) spectroscopy. The partial least-squares projection to laten t structure makes use of all of the data, and the latent variables created by the method make use of hidden or partially separated peaks for quantitat ion. This paper illustrates the usefulness of the partial least-squares mul tivariate calibration method as an efficient tool to determine the polymorp hism of a drug. Also, the analysis suggests the use of information from the modeling as diagnostic tools to gain more insight from the data. In partic ular, the diagnostic tools allow an analyst to assess design characteristic s and any shortcomings of a calibration experiment for the polymorphism of a drug compound.