SERS-based trace-level quantification of sulindac: Spectroscopic and molecular modeling evaluation

Sulindac is a common non-steroidal anti-inflammatory drug used for the treatment of various types of cancer. However, its overdose or long-term exposure may increase the risk of heart attack and intestinal bleedings. In the present study, a reliable spectroscopic approach for the trace-level identification and quantification of sulindac using the surface-enhanced Raman scattering (SERS) technique and employing silver nanoparticles (AgNPs) substrates was developed. An unprecedented sensitivity with a wide dynamic range (1 × 10⁻² M to 1 × 10⁻⁹ M) and a low detection limit (1 × 10⁻¹⁰ M) was achieved. Molecular modeling results for the interaction of sulindac molecules with silver nanoparticles were correlated with the experimental findings. Significant enhancements, due to charge transfer processes, in the Raman bands at 1111, 1653, 1607 and 1340 cm⁻¹ corresponding to the -S=O stretching, -C=O stretching, -C=C- stretching and ring stretching vibrations were observed. The approach developed in this work has the potential for sensitive quantification of sulindac and could be extended to structurally relevant drugs.