Abstract
Hydroquinone (HDQ) is a natural depigmenting agent, which is commonly used in skin-toning preparations. The safety and greenness of analytical methods of HDQ quantification were not considered in previous literature. Therefore, a highly sensitive and ecologically greener reversed-phase high-performance thin-layer chromatography (RP-HPTLC)-based assay was established for HDQ estimation in four different commercial whitening creams (CWCs). The binary ethanol−water (60:40, v·v−1) mixture was utilized as the green solvent system. The estimation of HDQ was carried out at 291 nm. The present RP-HPTLC-based assay was linear in the 20−2400 ng band−1 range. The present analytical method was highly sensitive based on the detection and quantification data. The other validation parameters, such as accuracy, precision, and robustness, were also suitable for the determination of HDQ. Maximum HDQ quantities were obtained in CWC A (1.23% w·w−1) followed by CWC C (0.81% w·w−1), CWC D (0.43% w·w−1), and CWC B (0.37% w·w−1). The analytical GREEnness (AGREE) score for the present analytical method was estimated as 0.91, indicating the excellent greener characteristics of the present RP-HPTLC assay. These results suggest that the present analytical method is highly sensitive and ecologically sustainable for the quantitation of HDQ in its commercial formulations.