**2.9 Characterization of crystalline forms of paclitaxel**

X-Ray diffraction (XRD) measurements were made by using an x-ray diffractometer (D8 Discover, Bruker, Karlsruhe, Germany) with the general area detector diffraction system (GADDS, Bruker, Karlsruhe, Germany). The Cu Kα radiation of wavelength 1.542 Å was provided by the x-ray generator (FL CU 4 KE, Bruker, Karlsruhe, Germany) operating at 40 kV and 45 mA. Sample-to-detector distance was 300 mm. Exposure time was 1 ~ 5 h. To avoid air scattering, the beam path was filled with helium. The surface morphology of paclitaxel was observed by scanning electron microscopy (SEM; Hitachi S-2460N, Japan) at an accelerating voltage of 15 kV after Pt/Au sputter coating (Hitachi E1010 Ion sputter, Japan).
