ABSTRACT
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.
Subject(s)
Fats/chemistry , Oils/chemistry , Fats/chemical synthesis , Oils/chemical synthesis , Spectroscopy, Fourier Transform Infrared , Spectrum Analysis, Raman , Water/chemistry , X-Ray DiffractionABSTRACT
By performing extensive Monte Carlo simulations we show that the infinitely fast driven lattice gas (IDLG) shares its critical properties with the randomly driven lattice gas (RDLG). All the measured exponents, scaling functions, and amplitudes are the same in both cases. This strongly supports the idea that the main relevant nonequilibrium effect in driven lattice gases is the anisotropy (present in both IDLG and RDLG) and not the particle current (present only in the IDLG). This result, at odds with the predictions from the standard theory for the IDLG, supports a recently proposed alternative theory. The case of finite driving fields is also briefly discussed.
