Inhibition of naproxen crystallization by polymers: The role of topology and chain length of polyvinylpyrrolidone macromolecules.

This paper presents an innovative approach that utilizes self-synthesized homopolymers of polyvinylpyrrolidone (PVP) with different architectures as effective matrices for inhibiting the crystallization of naproxen (NAP). We have thoroughly investigated amorphous solid dispersions containing NAP and (i) self-synthesized linear PVP, (ii) self-synthesized three-armed star-shaped PVP, and (iii) self-synthesized linear PVP with a mass (M) corresponding to the length of one arm of the star polymer, as well as (iv) commercial linear PVP K30 as a reference. Differential scanning calorimetry (DSC), X-ray diffraction (XRD), and infrared spectroscopy (FTIR) studies, as well as molecular dynamics simulations were conducted to gain comprehensive insights into the thermal and structural properties, as well as intermolecular interactions in the NAP-PVP systems.

The existence of a strongly bonded layer in associating liquids within silica pores - a spectral and molecular dynamics study.

The properties of confined materials are assumed to be governed by the phenomena occurring at the interface, especially the formation of an irreversible adsorption layer (IAL), which has been widely discussed and detected in the case of thin polymer films and silica nanoparticles. In this paper, we present a novel experimental approach allowing us to reveal the formation of an IAL in two phenyl alcohols infiltrated into various mesoporous silica templates. The proposed methodology (based on evaporation) allowed us to detect the alterations in the OH and aromatic CH stretching vibration bands in infrared spectra, which were considered as evidence of the existence of IAL in constrained systems.

The Impact of Various Poly(vinylpyrrolidone) Polymers on the Crystallization Process of Metronidazole.

In this paper, we propose one-step synthetic strategies for obtaining well-defined linear and star-shaped polyvinylpyrrolidone (PVP and PVP). The produced macromolecules and a commercial PVP K30 with linear topology were investigated as potential matrices for suppressing metronidazole (MTZ) crystallization. Interestingly, during the formation of binary mixtures (BMs) containing different polymers and MTZ, we found that linear PVPs exhibit maximum miscibility with the drug at a 50:50 weight ratio (/), while the star-shaped polymer mixes with MTZ even at a 30:70 /.

Pressure-Induced Aggregation of Associating Liquids as a Driving Force Enhancing Hydrogen Bond Cooperativity.

The behavior of hydrogen bonds under extreme pressure is still not well understood. Until now, the shift of the stretching vibration band of the X-H group (X = the donor atom) in infrared spectra has been attributed to the variation in the length of the covalent X-H bond. Herein, we combined infrared spectroscopy and X-ray diffraction experimental studies of two H-bonded liquid hexane derivatives, i.