Formation of Pseudopolymorph and Irregular Shape Crystals in the Process of myo-Inositol Crystallization

摘要

Myo-lnositol is a kind of saccharide alcohol, used as sweetnings and API (Active Pharmaceutical Ingredient). Myo-Inositol crystals are soluble in water and have crystal structure of anhydrate and dihydrate, when they crystallize in water and/or water-ethanol system. But crystallization phenomena of myo-Inositol has not been cleared yet, such as relationship between pseudopolymorph transition and shape of crystals. We carried out cooling and drowning-out crystallization(ethanol addition) experiments batchwisely. Effect of temperature and solvent ratio on the solubility of myo-Inositol anhydrate and dihydrate was obtained, to recognize that myo-Inositol shows enantiotropic system. Considering this system, selective crystallization was done, to find out that irregular shape crystals are produced, when myo-inositol dihydrate crystallizes, and also the origin of irregular shape crystals exists in the early stage of crystallization, such as nucleation stage. Ratio of irregular shape crystals increases with increase in the volume of ethanol addition and also etahnol addition rate. Mechanism of irregular shape crystals formation was discussed, to verify that they are produced as a kind of twin crystals, caused by the myo-Inositol dihydrate crystal structure.