János Bolyai Research Scholarship of the Hungarian Academy of Sciences
Veklury™ by Gilead Sciences, Inc., containing antiviral drug, remdesivir (REM) has
received emergency authorization in the USA and in Europe for COVID-19 therapy. Here,
for the first time, we describe details of the non-covalent, host-guest type interaction
between REM and the solubilizing excipient, sulfobutylether-beta-cyclodextrin (SBECD)
that results in significant solubility enhancement. Complete amorphousness of the
cyclodextrin-enabled REM formulation was demonstrated by X-ray diffraction, thermal
analysis, Raman chemical mapping and electron microscopy/energy dispersive spectroscopy.
The use of solubilizing carbohydrate resulted in a 300-fold improvement of the aqueous
solubility of REM, and enhanced dissolution rate of the drug enabling the preparation
of stable infusion solutions for therapy. 2D ROESY NMR spectroscopy provided information
on the nature of REM–excipient interaction and indicated the presence of inclusion
phenomenon and the electrostatic attraction between anionic SBECD and nitrogen-containing
REM in aqueous solution.
