RAMAN SUPPLEMENT 1800 cm-1 , plotted in Figure 9, because of the


disorder in the crystalline states which induces similar local order in amorphous and both crystalline forms. Caffeine was recently used as a model API to analyse phase transformation induced by a tabletting process29


from a


mixture of form I of caffeine and excipients. Partial transformations of form I toward form II of caffeine were detected in tablets, analysed by micro Raman investigations in the low-frequency range. The method developed for determining the transformation rate (I → II) during the isothermal aging at 90°C30


was used to obtain a mapping


within tablets (at the microscopic level) of the degree of transformation, induced by the manufacturing process.


Evidence of a disordered metastable state in racemic ibuprofen Disordered states can have physical properties different from those of ordered stable states such as solubility, which can lead to different bio-availabilities. Recent Raman investigations in racemic ibuprofen (IBP) have revealed a significant disorder in phase II of IBP, not detected by X-ray diffraction31


. Figure 10 (page 18) shows the reduced intensity and the Raman


FIGURE 9 Raman spectra in the molecular fingerprint region of the liquid state and in both crystalline forms of caffeine


susceptibility of IBP in the glassy state, the disordered (phase II) and ordered (phase I) states at the same temperature. No trace of long-range order, i.e. phonon peaks, is identified in the spectra (Ir(ν) and χ”(ν)) of phase II. However, some shoulder in Ir


(ν)- and χ”(ν)-spectra


correspond to phonon peaks of phase I, and can be considered as Raman signatures of the long- range order in phase I. The Ir(ν) spectrum of phase II reveals an additional intensity at the low frequencies compared to the spectrum of the glass, indicating the presence of remaining


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