Lyotropic behavior of Gelucire 50/13 by XRD, Raman and IR spectroscopies according to hydration

• X-rays and vibrational behavior of Gelucire 50/13 at T = 24 °C.
• X-Rays and Vibrational behavior of Gelucire according to the hydration.
• For the first time, we have assigned all vibrational modes of the Gelucire 50/13.
• These modes in this spectral range are very sensitive to environmental changes.

The present paper discuss the structural and vibrational properties of polyoxyethylene glycol glycerides (Gelucire 50/13) during the hydration with increasing water from 0% to 80%. The Gelucire 50/13 used as sustained release matrix forming agent in pharmaceutical applications and it was essentially studied by Small and Wide Angle X-ray Scattering (SWAXS), Fourier transform infrared spectroscopy (FTIR) and Raman spectroscopy according to the rate of hydration. The hydration behavior of this amphiphilic excipient has been investigated in the spectral range 4000–0 cm−1 in Raman spectroscopy, and 4000–600 cm−1 in FTIR. At increasing water contents Gelucire 50/13 forms successive bicontinuous to micellar supramolecular structures, and the vibrational changes were directly correlated with this conformational changes of the Gelucire structure. Overall, Raman and IR spectroscopy clearly demonstrated that the different functional groups studied could be characterized independently, allowing for the understanding of their role in Gelucire polymorphism.