2020 EJRNL PP Sarah K. Mann -1.pdf
Terbatas Irwan Sofiyan
» ITB
Terbatas Irwan Sofiyan
» ITB
Liquid forms of pharmaceuticals (ionic liquids and
deep eutectic solvents) offer a number of potential advantages over
solid-state drugs; a key question is the role of intermolecular
hydrogen bonding interactions in enabling membrane transport.
Characterization is challenging since high sample viscosities, typical
of liquid pharmaceutical formulations, hamper the use of
conventional solution NMR at ambient temperature. Here, we
report the application of magic-angle spinning (MAS) NMR
spectroscopy to the deep eutectic pharmaceutical, lidocaine
ibuprofen. Using variable temperature MAS NMR, the neat
system, at a fixed molar ratio, can be studied over a wide range
of temperatures, characterized by changing mobility, using a single
experimental setup. Specific intermolecular hydrogen bonding interactions are identified by two-dimensional 1H?1H NOESY and ROESY MAS NMR experiments. Hydrogen-bonding dynamics are quantitatively determined by following the chemical exchange process between the labile protons by means of line-width analysis of variable temperature 1H MAS NMR spectra.