Acoustic-like dynamics of amorphous drugs in the THz regime

TL;DR

This study explores the high-frequency acoustic dynamics of amorphous drugs in the THz regime, revealing phonon-like behavior and providing insights into their sound velocity and attenuation properties.

Contribution

It presents the first investigation of THz dynamics in amorphous pharmaceuticals, linking acoustic behavior with molecular mobility and fragility.

Findings

Evidence of phonon-like acoustic dynamics in amorphous drugs

Determination of sound velocity and attenuation in the THz regime

Discussion of the relation between fast and slow molecular degrees of freedom

Abstract

The high frequency dynamics of Indomethacin and Celecoxib glasses has been investigated by inelastic x-ray scattering, accessing a momentum-energy region still unexplored in amorphous pharmaceuticals. We find evidence of phonon-like acoustic dynamics, and determine the THz behavior of sound velocity and acoustic attenuation. Connections with ordinary sound propagation are discussed, along with the relation between fast and slow degrees of freedom as represented by non-ergodicity factor and kinetic fragility, respectively.