J. Planar Chromatogr. 34, 243-252 (2021). HPTLC of dapagliflozin (1) and metformin (2) on silica gel with methanol - ethyl acetate - ammonium acetate 60:40:1. Quantitative determination by absorbance measurement at 220 nm. The hRF values for (1) and (2) were 79 and 31, respectively. Linearity was between 20 and 100 ng/zone for (1) and 500 and 2500 ng/zone for (2), respectively. Intermediate precisions were below 2 % (n=5). The LOD and LOQ were 3 and 10 ng/zone for (1) and 11 and 34 ng/zone for (2), respectively. Recovery was between 100.0 % and 101.6 % for (1) and 99.7 % and 101.1 % for (2).

Revista Bio Ciencias. 6, 670 (2019). HPTLC of the leaves of Turnera diffusa on silica gel with ethyl acetate - acetic acid - formic acid - water 100:11:11:27. Detection by spraying with 1 % 2-aminoethyl diphenyl borate in methanol (NP) and with 5 % polyethylene glycol 4000 in ethanol (PEG). Qualitative analysis under UV light at 254 and 366 nm.

Phytochem. Anal. 33, 83-93 (2022). HPTLC of table olives (Olea europaea) on silica gel with dichloromethane - methanol - acetic acid 45:5:1. Detection by spraying with sulfuric vanillin reagent (5 % vanillin in methanol - 5 % sulfuric acid in methanol 1:1) and under UV light at 254 and 366 nm. Further analysis by nuclear magnetic resonance. 

Phytochem. Anal. 33, 115-126 (2022). HPTLC bioautography of 14 Egyptian plants on silica gel with methylene chloride - methanol 9:1 (system I) or ethyl acetate - methanol - water - glacial acetic acid 120:20:16:1 (system II). Detection by spraying with anisaldehyde/sulfuric acid reagent. Aromatase inhibitory assay was performed by dipping into 112.5 mL cofactor solution (containing 4.5 mL of 0.5 % sodium phosphate buffer, 4.5 mL NADPH regenerating system solution A and 0.9 mL NADPH regenerating system solution B and then completed to volume with distilled water), followed by incubation at 37 °C for half an hour, then re-immersed in 75 mL aromatase E/S mix (containing 120 μL aromatase enzyme, 0.03 mL DBF and 3 mL albumin dissolved in 0.075 M potassium phosphate buffer) and re-incubated for another half an hour. Enzymatic reaction was terminated by immersing plates into 2N sodium hydroxide stop solution. Active zones were observed under UV 366 nm. Calculation of the inhibition zones was performed by reciprocal iso-inhibition volume (RIV) that is based on measuring the zone pixel intensity. The hRF values for chrysin were 63 and 91 in systems I and II, respectivley. The intermediate precision was below 3 % (n=3). Linearity was between 0.1 and 0.3 μg/zone. LOD and LOQ were 80 and 206 ng/zone, respectively. Recovery was between 92.5 and 106.5 %. Two quantification methods, the peak area and RIV method were compared and the RIV method showed superiority over the peak area method with %RSD values of 0.98 and 1.49 compared with 2.86 and 3.58, respectively.

J. of Chromatogr. Sci., 59 (10) 909-922 (2021). Development of a green stability indicating method for the quantitative determination of tenofovir alafenamide and its by-products produced under stress conditions. HPTLC on silica gel with n-butanol - acetic acid 7:3 and detection at 260 nm. Beer’ law was obeyed over the concentration range of 0.1- 4 μg/zone. Also micellar UPLC method. Both methods are validated according to ICH guidelines and successfully applied to the analysis of the drug in its tablets. In addition, their greenness was assessed using three different tools indicating their least hazardous effect on the environment.

Chinese J. Food & Drug 23 (5), 411-415 (2021). Dashanzha tablet is a Chinese patent medicine with the function of appetizing and digestion, used for food accumulation caused by loss of appetite, indigestion, abdominal distension. For quality control, TLC of the petroleum ether extracts on silica gel with cyclohexane - methylene dichloride - ethyl acetate - glacial acetic acid 200:50:80:1. Detection by spraying with 10 % sulfuric acid in ethanol and heating at 105 ℃ until the zones are visible in daylight. Identification by fingerprint comparison with the standard ursolic acid and the standard ingredient drug undergone the same procedure in parallel. Satisfactory results were achieved by using plates from different manufactures and under varying temperature and humidity conditions.

J. Chromatogr. Sci., 59 (10), 964-970 (2021). Introduction of an accurate and sensitive method for the simultaneous determination of thioctic acid, benfotiamine and cyanocobalamin in bulk powders and in their pharmaceutical formulation. TLC on silica gel with methanol - chloroform - heptane-1 - o.4 % sulfonic acid sodium salt 70:30:1. Determination by densitometric evaluation at 240 nm. The hRf values were 17, 48 and 75 for cyanocobalamin, benfotiamine and thioctic acid, respectively.

Chinese J. Ethnomed. & Ethnopharm. (10), 36-39 (2021). Huangjia Ruangan granules is a TCM preparation, which relaxes the liver and promotes blood circulation, and is used for treating liver fibrosis and early cirrhosis, spleen deficiency, liver depression and blood stasis. (A) Identification of Salvia miltiorrhiza Bge, Pueraria lobata (Willd.) Ohwi, and Paeoniae rubra root, by TLC of the methanol extracts, the control solutions lacking the three drugs, and the standards tanshinone IIA, puerarin, paeoniflorin, on silica gel first with chloroform – methanol – water 70:25:2.5 to 5 cm and then with toluene – ethyl acetate 24:1 to 8 cm; detection by spraying with 5 % vanillin in sulfuric acid – ethanol 1:200 and heating at 105 ˚C until the zones are visible in white light and UV 365 nm. (B) Identification of Astragali Radix, Panax notoginseng (Burkill) F. H. Chen ex C. H.) and Radix Bupleuri, by TLC of the methanol extracts, the control solutions lacking the three drugs and the standards astragaloside lV, notoginsenoside R1 and saikosaponin A, on silica gel with butanol – ethyl acetate – water 4:3:5 to 17 cm, detection by spraying with 2 % ethanol p-dimethylaminobenzaldehyde solution - sulfuric acid 2:3 and heating at 80 ˚C until the zones are visible, evaluation in white light and at UV 365 nm. The method was successfully applyed to identify six major ingredients in Huangjia Ruangan granules on the same plate through multi-information obtained, and proved to be simple, fast, specific, reproducible, robust and well suitable for the purpose.