Exploring molecular reorientations in amorphous and recrystallized felodipine at the microscopic level

Abstract

Molecular reorientations were studied in amorphous, partially and fully recrystallized felodipine using a set of experimental methods: high-resolution solid-state nuclear magnetic resonance (NMR), relaxometry NMR and quasielastic neutron scattering (QENS).

Low-Frequency Raman Spectroscopy as an Avenue to Determine the Transition Temperature of β- and γ-Relaxation in Pharmaceutical Glasses

“…In this regard, molecular mobility encompassing both local and global molecular motions can be regarded as a precursor for physical instability in both single and multicomponent amorphous phases as a number of studies have showcased a direct link between these properties in the glassy and supercooled states, respectively. − For pharmaceutically relevant manufacturing and storage conditions, identification of the β-relaxation related to localized molecular motions can be especially useful for predicting the physical stability of the disordered APIs in relation to these environments . However, accessing this information can prove challenging as it often requires the use of more specialized analytical techniques such as broadband dielectric spectroscopy (BDS), solid-state nuclear magnetic resonance (ssNMR), quasi-elastic neutron scattering, , or dynamic mechanical analysis (DMA), , which can also require prolonged and/or complicated data acquisition protocols to be employed.…”

“…5−7 For pharmaceutically relevant manufacturing and storage conditions, identification of the β-relaxation related to localized molecular motions can be especially useful for predicting the physical stability of the disordered APIs in relation to these environments. 8 However, accessing this information can prove challenging as it often requires the use of more specialized analytical techniques such as broadband dielectric spectroscopy (BDS), 9 solid-state nuclear magnetic resonance (ssNMR), 10 quasi-elastic neutron scattering, 10,11 or dynamic mechanical analysis (DMA), 8,12 which can also require prolonged and/or complicated data acquisition protocols to be employed.…”