Moisture induced polymorphic transition of mannitol and its morphological transformation.

摘要: The effects of moisture on the polymorphic transition crystalline mannitol were investigated. Mannitol has three forms, and was classified as alpha, beta, delta form, respectively, by Walter-Levy (C.R. Acad. Sc. Paris Ser. C (1968) 267, 1779). water uptake form greater than that beta when each stored at 97%RH (25 degrees C). different powder X-ray diffraction patterns obtained before after humidification confirmed a induced from to had occurred. Morphological changes also observed with an increase in specific surface area sample 0.4 2.3 m(2)/g being found exposure humidity. Thus it suggested higher hygroscopicity newly formed arose gradual form. When considering mechanism this transition, results molecular modelling, cross-polarisation/magic angle spinning (CP/MAS) solid-state NMR spectra scanning electron-micrographs suggest molecules act loosener facilitate conversion result multi-nucleation.