Understanding Fenofibrate Release from Bare and Modified Mesoporous Silica Nanoparticles.

To investigate the impact of the surface functionalization of mesoporous silica nanoparticle (MSN) carriers in the physical state, molecular mobility and the release of Fenofibrate (FNB) MSNs with ordered cylindrical pores were prepared. The surface of the MSNs was modified with either (3-aminopropyl) triethoxysilane (APTES) or trimethoxy(phenyl)silane (TMPS), and the density of the grafted functional groups was quantified via H-NMR. The incorporation in the ~3 nm pores of the MSNs promoted FNB amorphization, as evidenced via FTIR, DSC and dielectric analysis, showing no tendency to undergo recrystallization in opposition to the neat drug.

Thermal behavior and molecular mobility studies in the supercooled liquid and glassy states of carvedilol and loratadine.

The thermal behavior of carvedilol and loratadine was studied by differential scanning calorimetry (DSC). The glass-forming ability, as well as the the tendency for crystallization from the glass (glass stability) and from the metastable and equilibrium melt were also investigated by DSC. In addition this technique was also used to characterize the glass transition of carvedilol and loratadine by determining the activation energy of the structural relaxation, the dynamic fragility, and the heat capacity jump associated with the glass transformation.

Impact of chirality on peculiar ibuprofen molecular dynamics: hydrogen bonding organization and syn vs. anti carboxylic group conformations.

Studies of the impact of chirality on amorphous states are scarce. Here, we present combined dielectric relaxation spectroscopy (DRS) experiments and molecular dynamics (MD) simulation investigations of homochiral and racemic ibuprofen in the liquid, undercooled liquid and glassy states. The influence of chirality is particularly investigated on the syn and anti conformations of the -COOH moiety of the ibuprofen molecule and its link to the peculiar Debye-like dynamical process detected in this compound.

Thermal Behavior and Slow Relaxation Dynamics in Amorphous Efavirenz: A Study by DSC, XRPD, TSDC, and DRS.

The analysis of the thermal behavior of efavirenz showed a high glass-forming ability and good glass stability of this glass-forming liquid at room temperature. No polymorphic forms were formed either by cold crystallization or by recrystallization from solvent acetone. The determination of the dynamic fragility by the differential scanning calorimetry, thermally stimulated depolarization currents (TSDC), and dielectric relaxation spectroscopy (DRS) techniques is unanimous in suggesting efavirenz as a moderately fragile liquid.