Serge Bresson

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

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 4000-0cm-1 in Raman spectroscopy, and 4000-600cm-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.

Temperature dependent Raman and X-ray diffraction studies of anhydrous milk fat

Raman spectroscopy was used to characterize the polymorphs and liquid state of anhydrous milk fat, with emphasis placed on the thermal evolution of the ester carbonyl stretching modes (1800-1700cm-1) and the comparative study of the Raman-active CC (1660cm-1) and CH (3000-2700cm-1) vibrational modes. Specific Raman signatures in the crystalline phase were found and attributed to the coexistence of two groups of triglycerides. This was confirmed using differential scanning calorimetry and X-ray diffraction methods. In the ester carbonyl band, the effect of changing temperature on both the number of modes and new defined intensity ratios was studied and enabled polymorph discrimination. CH stretching signals increased with polymorph stability, indicating the dominance of antisymmetric CH methylene vibrations as the anhydrous milk fats crystal lattice became more ordered. The change in intensity of the CH stretching bands as a function of temperature was used to probe the order-disorder transition.

The vibrational behavior of the mixture quercetin/Gelucire 50/13 at room and body temperature

The present paper discusses the vibrational properties of the mixture Gelucire-quercetin (from 1% to 5%) at room and body temperature. Quercetin is a flavonoid having beneficial properties biological and antioxidant, it is used in many fields as food, cosmetic and especially pharmaceutical but its use as a drug is affected by its low solubility. The Gelucire 50/13 used as sustained release matrix forming agent in pharmaceutical applications and it have demonstrated the ability to improve the dissolution as well as the absorption of poorly water-soluble drugs [1-4]. The mixture Gelucire-quercetin was essentially studied by Fourier transform infrared spectroscopy (FTIR) and Raman spectroscopy. The behavior of these two molecules has been investigated in the spectral range 4000-0 cm-1 in Raman spectroscopy, and 4000-600 cm-1 in FTIR.