Moisture Uptake of Polyoxyethylene Glycol Glycerides Used as Matrices for Drug Delivery: Kinetic Modelling and Practical Implications

The use of polymer blends to improve stability and performance of electrospun solid dispersions: The role of miscibility and phase separation

Solid dispersion-based nanofiber formulations of poorly soluble drugs prepared by electrospinning (ES) with a water-soluble polymer, can offer significant improvements in drug dissolution for oral drug administration. However, when hygroscopic polymers, such as polyvinylpyrrolidone (PVP) are used, environmental moisture sorption can lead to poor physical stability on storage. This study investigated the use of polymer blends to modify PVP-based ES formulations of a model poorly soluble drug, fenofibrate (FF), to improve its physical stability without compromising dissolution enhancement. FF-PVP ES dispersions demonstrated clear dissolution enhancement, but poor storage stability against high humidity. Polymer blends of PVP with Eudragit E, Soluplus and hypromellose acetate succinate (HPMCAS), were selected because of the low intrinsic moisture sorption of these polymers. The drug-polymer and polymer-polymer miscibility study revealed that FF was more miscible with Eudragit E and Soluplus than with PVP and HPMCAS, and that PVP was more miscible with HPMCAS than Eudragit E and Soluplus. This led to different configurations of phase separation in the placebo and drug-loaded fibres. The in vitro drug release data confirmed that the use of PVP-Eudragit E retained the dissolution enhancement of the PVP formulation, whereas PVP-Soluplus reduced the drug release rate in comparison to FF-PVP formulations. The moisture sorption results confirmed that moisture uptake by the polymer blends was reduced, but formulation deformation occurred to phase-separated blend formulations. The data revealed the importance of miscibility and phase separation in understanding the physical stability of the ES fibre mats. The findings provide insight into the design of formulations that can provide dissolution enhancement balanced with improved storage stability.

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.