In this paper, we present a novel way of stabilization of amorphous celecoxib (CEL) against recrystallization by preparing binary amorphous celecoxib-octaacetylmaltose (CEL-acMAL) systems by quench-cooling of the molten phase. As far as we know this is the first application of carbohydrate derivatives with acetate groups to enhance the stability of an amorphous drug. We found that CEL in the amorphous mixture with acMAL is characterized by a much better solubility than pure CEL. We report very promising results of the long-term measurements of stability of the CEL-acMAL binary amorphous system with small amount of stabilizer during its storage at room temperature. Moreover, we examined the effect of adding acMAL on molecular dynamics of CEL in the wide temperature range in both the supercooled liquid and glassy states. We found that the molecular mobility of the mixture of CEL with 10 wt % acMAL in the glassy state is much more limited than that in the case of pure CEL, which correlates with the better stability of the amorphous binary system. By dielectric measurements and theoretical calculations within the framework of density functional theory (DFT), we studied the role of acMAL in enhancing the stability of amorphous CEL in mixtures and postulated which interactions between CEL and acMAL molecules can be responsible for preventing devitrification.

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Micro‐Raman light scattering experiments on PbZrO3 (PZO) single crystal doped with Nb5+ have been investigated. Special attention was paid to the paraelectric (PE) phase in which nominally forbidden first‐order Raman spectra were detected at temperatures far above the phase transition TC. Complex Raman spectra were observed in the vicinity of three structural phase transitions. These results mainly from the coexistence of phases with different symmetries in a wide temperature range below TC. The Raman measurements have been compared with dielectric and optical observations and proved that polar nanoregions in a centrosymmetric lattice appear well above TC. It was shown that doping ABO3 perovskites with heterovalent ions like Nb5+ unbalances charge neutrality of the lattice and strongly extends the temperature range of polar regions. The investigations performed point out that in the PE matrix the interaction between electrons and lattice vibrations, as recently suggested for pure PZO, plays an important role.