Surface Mobility of Amorphous Indomethacin Containing Moisture and a Surfactant: A Concentration–Temperature Superposition Principle

• DOI: 10.1021/acs.molpharmaceut.2c00311
• Publication Date: 2022-07-11T14:11:28Z
• Authors: Yuhui Li; Junguang Yu; Xiao Tan; Lian Yu
• Keywords: Surface diffusion

An amorphous material can have vastly higher mobility on the surface than in bulk and, as a result, shows fast crystallization. Most materials contain multiple components, but effect of composition dynamics remains poorly understood. In this study, indomethacin was measured using method surface-grating decay presence moisture and surfactant Tween 20. It is found that both components significantly enhance mobility, their effects are well described by principle concentration–temperature superposition (CTS); is, same observed at Tg-normalized temperature T/Tg, where Tg composition-dependent glass transition temperature. For doped showing CTS, mechanism evolution for 1000 nm wavelength grating transitions from viscous flow high temperatures to diffusion low 1.04 Tg. surfactant-doped system, used value layer reflects enrichment (measured X-ray photoelectron spectroscopy). At concentration (>10% weight), rate surface-diffusion regime limited large, slow-diffusing molecules; case, CTS holds only viscous-flow regime. The allows prediction multicomponent materials.