Effect of Food-Grade Pharmaceutical Excipients on Physicochemical Behaviour of Quercetin Nanocomposites: Thermal and Non-Thermal Analysis

In this study, the compatibility of Quercetin (QC) nanocomposites with some selective food-grade pharmaceutical excipients was assessed using various thermal (DSC and TGA), non-thermal (P-XRD, FT-IR, and RAMAN spectroscopy, and FESEM) techniques. All the techniques were simultaneously used and correlated to detect the QC's compatibility with the selected excipients (CO, CCO, OA, T20, T60, and T80). DSC-TG studies showed that QC-CO and QC-T60 samples exhibited irregular degradation patterns, causing the drug's transformation from crystalline to amorphous. P-XRD results showed that the crystalline behavior of QC was retained in all the samples. However, the peak intensities were reduced and shifted in some samples. The Davg. value for all samples, including pure QC, was 26.80-76.07 nm. FT-IR and RAMAN studies demonstrated that bonds including –C=O stretching, C-C stretching (ring A), and -OH bonds (in ring A, B, and C) in pure QC play a crucial role in its interaction with excipients. Furthermore, the excipients' effect on QC's morphology using FESEM showed smoothening, fragmentation, and agglomeration of the drug. In conclusion, the possible drug-excipient incompatibility can be potentially determined with the help of these analytical methods. The physicochemical studies from this work may provide immense knowledge for the researchers and manufacturers involved in quercetin-based pharmaceutical and/or nutraceutical formulations.