In situ observation of Theophylline anhy-drous forms II, III, V, and I* using Variable-Temperature, Variable-Relative Humidity Powder X-ray Diffraction

Publisher: Triclinic Labs, Inc

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In situ observation of Theophylline anhy-drous forms II, III, V, and I* using Variable-Temperature, Variable-Relative Humidity Powder X-ray Diffraction

Theophylline was investigated using an Anton Paar Controlled Humidity Chamber (CHC+) attachment on a Rigaku SmartLab powder diffractometer to observe polymorphic transitions as a function of temperature and relative humidity. The experiments resulted in the observa-tion of Forms II, III, V, and I*. The results demonstrate that VT,VRH-PXRD is a powerful and relatively effective technique to discover polymorphs involved in phase transitions and ex-plore the thermodynamic temperature–relative humidity phase diagram. Keywords:Theophylline, temperature, relative humidity, powder X-ray diffraction, polymor-phism, phase transition.

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