An X-ray diffraction methods and Fourier transform infrared analysis with photoacoustic detector (FTIR-PAS) for estimation of the degree of crystallinity of crystalline E1040 formulation was established. The X-ray procedure to determine the crystallinity of E1040 was based upon the measurement of the total scattering and the scattering from the crystalline region of the drug. The FTIR-PAS procedures are based upon the measurement of the peak height ratio at 1628 cm-1 and measurement of the spectral region between 2400 and 3700 cm-1 by the Partial least squares (PLS) techniques. The data of the degree of crystallinity from the X-ray diffraction methods are consistent with the data from FTIR-PAS methods. The increase of the degree of crystallinity of the drug formulation decreased the decomposition rate of E1040. As a result, it had become apparent that two analytical procedures were actually valid. This assured optimizing process conditions which affect the improvement of crystallinity.
