Visualizing solvent mediated phase transformation behavior of carbamazepine polymorphs by principal component analysis.

The purpose of this research is to gain a greater insight into the hydrate formation processes of different carbamazepine (CBZ) anhydrate forms in aqueous suspension, where principal component analysis (PCA) was applied for data analysis. The capability of PCA to visualize and to reveal simplified structures that often underlie large data sets are explored. Different CBZ polymorphs were dispersed separately in aqueous solution, and then recovered and measured by FT-Raman spectroscopy. PCA was employed for visualizing the dynamics of the phase transformation from each CBZ polymorph to the dihydrate (DH). As a comparison to PCA visualization, the transformation process of each CBZ polymorph was quantified using PLS modeling. The results demonstrated that PCA has advantages in presenting the original data in terms of the differences and similarities, and also directly identify the statistical patterns in the data even when the data set is large. These advantages provided greater insight into the measured Raman spectra as well as the phase transformation process of CBZ polymorphs to the DH in aqueous environment.