We investigate the potential of surface plasmon polaritons at noble metal
interfaces for surface-enhanced chiroptical sensing of dilute chiral drug
solutions with nano-litre volume. The high quality factor of surface plasmon
resonances in both Otto and Kretschmann configurations enables the enhancement
of circular dichroism thanks to the large near-field intensity of such
plasmonic excitations. Furthermore, the subwavelength confinement of surface
plasmon polaritons is key to attain chiroptical sensitivity to small amounts of
drug volumes placed around ≃ 100 nm by the metal surface. Our
calculations focus on reparixin, a pharmaceutical molecule currently used in
clinical studies for patients with community-acquired pneumonia, including
COVID-19 and acute respiratory distress syndrome. Considering realistic dilute
solutions of reparixin dissolved in water with concentration ≤ 5 mg/ml and
nl volume, we find a circular-dichroism differential absorption enhancement
factor of the order ≃ 20 and chirality-induced polarization distortion
upon surface plasmon polariton excitation. Our results are relevant for the
development of innovative chiroptical sensors capable of measuring the
enantiomeric imbalance of chiral drug solutions with nl volume