Chinese J. Food & Drug 23 (3), 229-232 (2021). Non-benzodiazepines are inhibitors directly acting in the central nervous system, with sedative, anxiolytic and anticonvulsant effects. They are used as third generation sedative-hypnotic drugs to treat insomnia. However, it has been found that they are illegally added to some health foods on the market, which may cause long-term abuse and cause harm to the human body. Therefore, it is necessary to strenghten a rapid screening to detect the illegal addition of non-benzodiazepines to health foods, to improve the efficiency of supervision, and to crack down illegal practices.  TLC of ethyl acetate extracts of health foods adulterated with non-benzodiazepines, on silica gel with dichloromethane - methanol - ethyl acetate 17:2:6. Detection in UV 254 nm, identification by fingerprint comparison with the standards zolpidem, zalepron and zoppilon. Using this method, 65 batches of health food samples obtained from the market were screened, and four of them were suspected of illegal addition of zopiclone. This result is consistent with the analysis using both HPLC-DAD and HPLC-MS, and proved the  TLC method to be simple, fast, accurate, easy to operate, and well suitable for quick screening.

J Chromatogr Sci, 60 (10), 946 - 952 (2022). Study of the mechanism of micellar thin layer chromatography (MTLC) and development of a new simple and sensitive method for simultaneous separation of empagliflozin, linagliptin and metformin hydrochloride ternary mixture. TLC using a micellar mobile phase composed of methanol and aqueous solution of each of three different surfactants, sodium dodecyl sulphate (SDS), benzalkonium chloride (BAC) and polysorbate 80 (tween 80), in ratio of 2:3. Micellar TLC determination at 237 nm. Investigation of the quantitative structure - retention relationships by modeling, evaluating and validating with a molecular operating environment software. Discussion of the basis for selecting surfactants, for example the separation using SDS (anionic surfactant) and BAC (cationic surfactant) depended on ionization potential (AMI-IP), partition coefficient (logP (o/w)) and hydrogen bond donor atoms (a-don), whereas the separation using tween 80 depended mainly on the lipophilicity (RM0), solvation energy (E-sol) and Van der Waals energy (E-vdw).

Drug Standards of China 22 (3), 259-264 (2021). Gentianella acuta (Michx.) Hulten is a herbal traditional Chinese medicine, containing mainly efficacy components like diphenylpyrione, cycloether terpenoids, flavonoids, and triterpenoids. It has liver protection, hypoglycemic, anti-inflammatory and other pharmacological activities, and is used clinically to treat jaundice, headache, fever, dry mouth and bile fever etc. To establish a quality standard of the herb, TLC was used for the investigation of the chemical composition and fingerprints. TLC of methanolic extracts of 10 batches of Gentianella acuta  collected from different regions (A) for cycloether terpene components (gentiopicroside and swertimarin), on silica gel with ethyl acetate - methanol - water 4:1:1, detection under UV 254 nm, identification by comparison of the fingerprints with those of the standards gentiopicroside and swertimarin; (B) for terpenoids (oleanolic acid), on silica gel with chloroform - methanol - ammonium hydroxide 20:6:1, detection under UV 254 nm, identification by comparison of the fingerprints with those of the oleanolic acid standard; (C) for aqueous extracts (water-soluble components such as flavonoids and phenolic acids), on silica gel with 1-butanol - acetic acid - water 9:3:2, detection by spraying with 5 % aluminium trichloride solution and evaluation under UV 366 nm, identification by comparison of the fingerprints with those of the oleanolic acid standard. The results showed that the TLC profiles of 10 batches were very similar, and well consistent with the HPLC fingerprint results. In addition, gentiopicroside, swertimarin and oleanolic acid were identified by TLC in the medicine, thus can be used as the target components of the identification. Therefore, the results of this study can be used as the basis for the authenticity identification and quality evaluation of the medicine.

J Chromatogr Sci, 60 (6), 606-612 (2022). Simultaneous determination of sofosbuvir and daclatasvir, co-formulated as directly acting antiviral agents used for treatment of hepatitis C virus, by TLC on silica gel with ethyl acetate - hexane - methanol 18:1:1. Both substances were quantitatively separated in one analytical run. Quantitative determination by densitometry at 280 nm with linearity range of 0.4 - 25.4 μg/band for sofosbuvir and 0.4 - 12.8 μg/band for daclatasvir. The method is time- and cost-saving, which is even more important for some combinations on the market, such as Darvoni® tablets.

J Strait Pharm 33 (8), 46-48 (2021). Yinling Heji is a TCM drug, containing Artemisia capillaris Thunb., Scutellaria L., Radix Rehmanniae Preparata etc. It clears heat and dampness, is mainly used for the prevention and treatment of neonatal jaundice, and has a good effect on children with mild diseases. For quality control, microemulsion thin-layer chromatography on polyamide layer, (A) for Herba Artemisiae Scopariae, of methanol extracts of the test sample (TCM prescription drug), methanol extracts of the test sample without Herba Artemisiae Scopariae, methanolic extracts of Herba Artemisiae Scopariae and standard chlorogenic acid in methanol, (B) for Scutellaria L., methanol extracts of the test sample, methanol extracts of the test sample without Scutellaria L., methanolic extracts of Scutellaria L. and standard baicalin in methanol, (C) for Rhei Radix et Rhizoma, methanol extracts of the test sample, methanol extracts of the test sample without Rhei Radix et Rhizoma, methanolic extracts of Rhei Radix et Rhizoma, and standard emodin in methanol. Development with (sodium dodecyl sulfate - n-butanol - cyclohexane - water 27:63:10:300) - formic acid 9:1.

J. Planar Chromatogr. 35, 287-297 (2022). HPTLC of species of the grass family (Poaceae), coming from genera: Agrostis, Alopecurus, Anthoxanthum, Apera, Arrhenatherum, Avena, Brachypodium, Briza, Bromus, Calamagrostis, Corynephorus, Cynosurus, Dactylis, Danthonia, Deschampsia, Digitaria, Echinochloa, Elymus, Eragrostis, Festuca, Glyceria, Helictotrichon, Hierochloe, Holcus, Hordeum, Koeleria, Leymus, Lolium, Milium, Molinia, Nardus, Panicum, Phalaris, Phleum, Phragmites, Poa, Saccharum and Setaria on silica gel with ethyl acetate - methanol - water 4:1:1. Detection under UV light at 210, 254, 312 and 366 nm and in fluorescence mode with 312/370, 366/420 and 366/550 nm of excitation and emission filter, respectively. Principal component analysis (PCA) allowed the identifiation of six orthogonal trends in phytochemical composition. 
 

J. Planar Chromatogr. 35, 339-344 (2022). HPTLC of four goldenrod Solidago species (S. gigantea, S. canadensis, S. virgaurea and S. gramnifolia) on silica gel with n-hexane - isopropyl acetate - acetone 16:3:1. Detection by dipping into the cell suspension of the bioluminescent A. fischeri, followed by recording with 50 s exposure time. Further analysis was performed using high-resolution mass spectrometry. Main bioactive markers of the species were Z,Z-matricaria ester from S. virgaurea, solidagenone from S. canadensis, solidagoic acid A, and a dialdehyde clerodane diterpene from S. gigantea, and Z-dehydromatricaria ester from S. graminifolia. 

J Chromatogr Sci, 60 (4), 364-371 (2022). Borage oil, extracted from Borago officinalis Linn., is a well-known medicinal compound with various benefits. Development of an affordable, simple, reliable, rapid and easily accessible method for the estimation of gamma-linolenic acid (GLA) in borage oil by HPTLC on silica gel with hexane - toluene - glacial acetic acid 3:7:1. The hRf value of GLA was 53 ± 4. Quantiative determination by densitometry at 200 nm with an LOD and LOQ of 221 and 737 ng/band, respectively. The method was validated by investigation for parameters like linearity, accuracy, specificity and precision, and found to be highly sensitive for the estimation of GLA in the herbal oil samples and formulations.