The Physicochemical Investigation of 17β-Estradiol Crystalline Prepared by In Situ pH-Dependent Solubility Technique with Polyvinylpyrrolidone.

Micro-particles of 17β-estradiol (ED) were prepared with polyvinylpyrrolidone (PVP) by in situ pH-dependent solubility technique. Products were characterized using multiple instruments, and molecular interactions between ED and PVP were explored. Powder X-ray diffraction and thermal analysis revealed crystalline ED in the micro-particles is hemihydrated. PVP was also present in the micro-particles. Laser particle size analysis and scanning electron microscopy revealed thin slice morphology, which might have resulted from the influence of PVP. Moreover, the results of contact angle, specific surface area, and dynamic vapor sorption showed that the surface properties of products were improved. These physicochemical properties of the micro-particles resulted in an obvious improvement in dissolution rate. Fourier transform infrared spectroscopy and 1 H nuclear magnetic resonance revealed hydrogen bonding between ED and PVP. A method was established for the preparation of micro-particles through the addition of PVP during the reaction process.