[Research progress on the pretreatment and analysis of prohibited components of glucocorticoids in cosmetics]

Analyzing cosmetics is particularly important from a safety perspective owing to their widespread use in modern society. A wide range of ingredients and substances are restricted and/or prohibited to ensure that cosmetics are safe， with glucocorticoids among the prohibited substances. Glucocorticoids are important hormones that regulate the body's stress response； they are also widely used as effective anti-inflammatory and immunosuppressive agents in the clinic. However， long-term topical use can lead to allergic reactions and other human-health effects； consequently， their inclusion in cosmetics formulations is prohibited. Glucocorticoids are often illegally abused in cosmetics with the aim of enhancing their anti-allergic and whitening effects. However， analyzing cosmetics is challenging owing to matrix complexity， structural diversity， and the trace-level （μg/kg） presence of glucocorticoids. Rapid and efficient sample pretreatment techniques and sensitive analytical methods are required to address these challenges， which necessitates separating/analyzing glucocorticoids and optimizing the separation/detection workflow. This review presents research progress into sample-pretreatment and analytical methods used to analyze and detect glucocorticoids in cosmetics during the 2010-2024 period. Sample preparation is a critical step when analyzing cosmetics because complex matrices can seriously interfere with the determination of target analytes； hence some separation or enrichment methods often need to be employed when analyzing glucocorticoids in cosmetics. These methods mainly include field-assisted extraction methods， such as ultrasonic-assisted， vortex-assisted， and electric-field-assisted extraction， phase-partitioning methods， such as liquid-liquid extraction and liquid-liquid microextraction， as well as phase-adsorption methods， such as solid-phase microextraction and solid-phase， dispersive-solid-phase， and magnetic-solid-phase extraction. Cosmetics are divided into three categories according to the matrix： aqueous， emulsion， and cream. Creams and emulsions contain many wax-based and lipid substances that often need to be separated and enriched by methods that involve binding field assistance or phase separation， with solid-phase extraction associated with the most （more than 40%） literature reports. Glucocorticoid dissolution is often accelerated by ultrasonic-assisted or vortex-assisted methods prior to solid-phase extraction or solid-phase microextraction. In addition， methods used to analyze and detect glucocorticoids in cosmetics mainly included liquid-chromatography， chromatography-mass spectrometry， and capillary electrophoresis in the 2010-2024 period， as well as rapid detection methods that are discussed in this review. Statistically， 64% of the reports in this timeframe use chromatography-mass spectrometry methods， with chromatography-related methods accounting for 85% of the methods used to analyze and detect glucocorticoids in cosmetics. Methods for rapidly testing glucocorticoids in cosmetics， including spectroscopy and colorimetry， among others， are also presented in this review owing to the sheer size of the market for beauty products and the high demand for on-site testing. With this background in mind， the separation and analysis of glucocorticoids in cosmetics are anticipated to show developmental trends. Currently， solid-phase extraction and other pretreatment technologies， along with liquid chromatography- and chromatography-mass spectrometry-based detection techniques are the main quality-control avenues for cosmetics. However， on the one hand， glucocorticoid structural diversity and the continuous discovery and use of new glucocorticoids necessitate the development of new analytical methods. In particular， integrating high-resolution mass spectrometry， nuclear magnetic resonance spectroscopy， and big-data-analysis methods when developing efficient qualitative and quantitative analytical methods is significantly important from a practical perspective. On the other hand， the development of rapid， efficient， and universal pretreatment technologies for glucocorticoids is key to effectively separating and analyzing them in cosmetics and is expected to receive increasing levels of attention. Furthermore， rapid analysis， especially analytical techniques suitable for rapid on-site screening， are expected to become focuses for the detection of glucocorticoids in cosmetics in response to the growing regulatory requirements of the cosmetics market. Integrating sample-pretreatment and analytical-detection methods， along with the development of visualized， integrated， and automated rapid-detection technologies， is expected to facilitate rapid on-site sampling and high-throughput cosmetics testing.