Stability-Indicating High-Performance Thin-Layer Chromatographic Method for the Simultaneous Determination of Quercetin and Resveratrol in the Lipid-Based Nanoformulation

A simple, sensitive, specific, rapid, and accurate high-performance thin-layer chromatographic (HPTLC) method has been developed and validated for the simultaneous estimation of quercetin (QCT) and resveratrol (RSV). Chromatographic separation was performed over pre-coated TLC plates (60 F254, 20 × 10 cm, 250 μm thickness, Merck, Darmstadt, Germany) through a linear ascending technique. Among the different combinations of the mobile phases used, the best separation was achieved in the toluene—ethyl acetate—formic acid (6:2.5:1.5, V/V) mixture. Detection and quantification were achieved at 286 nm through the spectrodensitometric analysis. Analytical performance of the proposed HPTLC method was validated according to the International Conference for Harmonization (ICH) guidelines with respect to linearity, accuracy, precision, detection, and quantitation limits, robustness, and specificity. The calibration curves were linear in the range of 50–2500 ng per spot for both QCT and RSV, with a correlation coefficient (R2) of 0.998 and 0.997 for the QCT and RSV, respectively. The detection limits were 122.33 and 370.7 for QCT and RSV, respectively, and the quantitation limits were 27.35 and 82.93 for QCT and RSV, respectively. Additionally, forced degradation studies of QCT and RSV were established. The validated HPTLC method was successfully applied to the simultaneous determination of QCT and RSV in the nanoformulation.