Related Experiment Video
Updated: May 30, 2026

Methods of Ex Situ and In Situ Investigations of Structural Transformations: The Case of Crystallization of Metallic Glasses
Published on: June 7, 2018
The phase (trans)formation and physical state of a model drug in mesoscopic confinement
Tina Ukmar1, Aljaž Godec, Odon Planinšek
1National Institute of Chemistry, Hajdrihova 19, SI-1000 Ljubljana, Slovenia.
Abstract:
Compounds embedded into mesoporous or even microporous matrices are interesting for many emerging applications, such as novel catalysts, sensors, batteries, hydrogen storage materials or modern drug delivery devices. We report on two unexpected phenomena regarding the structural and dynamic properties of a model drug substance (indomethacin) when confined in mesoscopic matrices. Firstly, we show that the confinement directs the crystallization of the drug into a stable polymorph that is not otherwise formed at all; its relative amount depends on the pore size. This phenomenon is also explained theoretically using a modified classical heterogeneous nucleation theory. Secondly, we demonstrate that--even at relatively low volume fractions--the confined drug forms a condensed phase in a way that obstructs the passage of the pore channels. This may have far-reaching consequences for understanding the mechanisms of drug release from porous matrices.
Related Concept Videos
Phase Transitions
Phase Transitions
States of Matter and Phase Changes
The Phase Rule
Phase Transitions: Melting and Freezing
Phase Changes
A substance melts or freezes at a temperature called its melting point and boils or condenses at its boiling point. These temperatures depend on pressure. High pressure favors the denser form of the substance, so typically, high pressure...

