J. Sep. Sci. 43, 2981-2988 (2020). HPTLC of citicoline (1) and piracetam (2) in presence of their degradation products on silica gel with methanol - chloroform - ammonium chloride buffer 9:1:2. Quantitative determination by absorbance measurement at 230 nm. The hRF values for (1) and (2) were 15 and 85, respectively. Linearity was between 0.2 and 4 µg/zone for both (1) and (2). Intermediate precision was below 2 % (n=3). The LOD and LOQ were 56 and 180 ng/zone for (1) and 53 and 170 ng/zone for (2), respectively. Average recovery was 100.9 % for (1) and 99.8 % for (2).

J. Planar Chromatogr. 33, 219-229 (2020). HPTLC of carbamazepine (1) and its degradation product iminostilbene (2) on silica gel with petroleum ether - acetone 7:3. Quantitative determination by absorbance measurement at 230 nm. The hRF values for (1) and (2) were 12 and 63, respectively. Linearity was between 0.1 and 1.4 µg/zone for (1) and 0.1 and 1.2 µg/zone for (2). Intermediate precision was below 2 % (n=3). The LOD and LOQ were 0.03 and 0.09 µg/zone for (1) and 0.03 and 0.09 µg/zone for (2), respectively. Average recovery was  99.7 % for (1) and 99.7 % for (2).

J. Ethnopharmacol. 235, 361-374 (2019). HPTLC of colchicine (1) and withaferin A (2) in the polyherbal ayurvedic formulation Peedantak Vati (PV) on silica gel with chloroform - 
methanol - water - formic acid 140:13:2:4. Quantitative determination by absorbance measurement at 218 nm. The hRF values for (1) and (2) were 22 and 28, respectively. LOD and LOQ were 40 and 120 ng/zone for (1) and 120 and 240 ng/zone for (2), respectively.  

Asian J. Chem. 20(4), 2531-2538 (2008). TLC of melatonin on silica gel with toluene - ethyl acetate - formic acid 10:9:1. Quantitative determination by absorbance measurement at 290 nm. The method was linear in the concentration range of 100 to 600 ng/spot. The recovery of the drug from tablets (by standard addition method) was 99.7 %. Statistical analysis proves that the method is repeatable, selective and accurate for the estimation of the drug. Forced degradation studies showed the effect of variations in pH, UV light and high temperature on the stability of melatonin. As the proposed method could effectively separate the drug from its degradation products, it can be employed as a stability indicating method.

62nd Indian Pharmaceutical Congress Abstract No. F-235 (2010). TLC of metformin and glimepiride on silica gel with 0.5 % ammonium sulfate – water – methanol – ethyl acetate 2:2:1:1. Quantitative determination by absorbance measurement at 254 nm. The method was found to be linear in the range of 300-500 ng/band for glimepiride and 150-250 µg/band for metformin.

J. Planar Chromatogr. 28, 395-397 (2015). HPTLC of 25-B-NBOMe (a N-(2-methoxy)benzyl-substituted phenylethylamine hallucinogen) in seized blotters (small, square pieces of absorbant paper impregnated with LSD or other hallucinogens) on silica gel with cyclohexane – toluene – diethylamine 15:3:2. Quantitative determination by absorbance measurement at 298 nm. The hRF value for 25-B-NBOMe was 34. Linearity was in the range of 19-115 μg/zone. LOD and LOQ were 7 and 22 μg/zone. The intermediate precision was below 6.3 % (n=6). Average recovery was 98 %.

J. Planar Chromatogr. 2, 163-164, (1989). Study of the chromatographic behavior of cis- and trans-2-m-chlorophenyl-, and 2-benzylhexahydroquinazolin-4(3H)-ones on silica by two-dimensional development with two times the same of four solvents at an interval of 20 hours. Detection by exposure to chlorine followed by spraying with TMD reagent. Ring-opening and ring-closure reactions were concluded.

Acta Pharmaceutica Hungarica 67, 81-88 (1997). TLC of glibenclamide on silica with benzene - acetic acid - ethyl acetate - acetone 65:6:12:30 or chloroform - cyclohexane - ethanol - acetic acid 9:9:1:1.