Interactions of topiramate with polyethylene glycol 8000 in solid state with formation of new polymorph

Topiramate [2,3:4,5-bis-O-(1-methylethylidene) β-d-fructo-pyranose sulfamate] was found to form a new polymorphic form in the presence of polyethylene glycol 8000 (PEG). Comparative study of the solid state interactions of PEG and structural topiramate analogue lacking sulfamate group (Diacetone d-fructose) indicated that the sulfamate moiety was essential for the formation of the new polymorph. The drug–polymer interactions were investigated using differential s canning calorimetry (DSC), Fourier Transform Infrared Spectroscopy (FTIR) and hot stage microscopy. The new polymorphic form was characterized using variable temperature powder X-ray diffraction (VTPXRD) and solid state Nuclear Magnetic Resonance (ssNMR). The new polymorph was found to form only in the presence of PEG at specific weight ratios.

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