J. Liq. Chrom. Rel. Tech. 38, 271-282 (2015). HPTLC of (1) terazosin, (2) doxazosin, (3) prazosin, and (4) alfuzosin in plasma on silica gel with acetonitrile - phosphate buffer 3:7 at pH 3. Quantitative determination by absorbance measurement at 332 nm. The hRF values of (1) to (4) were 52, 47, 53 and 41, respectively. Linearities were between 10 and 100 ng/zone for (1) and (2), between 15 and 75 ng/zone for (3) and between 5 and 100 ng/zone for (4). The LOD and LOQ were 4 and 9 ng/zone for (1), 5 and 10 ng/zone for (2), 7 and 14 ng/zone for (3) and 4 and 5 ng/zone for (4), respectively. The intermediate intra-day and inter-day precisions were below 2.6 % (n=6). Mean recoveries were found in the range of 94.2-99.9 %.

J. Planar Chromatogr. 20, 335-339 (2007). TLC of etoricoxib (rofecoxib as internal standard) on silica gel in a filter-paper-lined twin-trough chamber previously saturated with mobile phase vapor for 30 min with toluene - 1,4-dioxane - methanol 17:2:1. Densitometric analysis of etoricoxib was performed in absorbance mode at 235 nm. The limits of detection and quantitation were 30 and 100 ng/zone, respectively.

Determination by using autoradio - layer chromatographic recorder.

J. Planar Chromatogr. 20, 149-152 (2007). HPTLC of nebivolol hydrochloride on silica gel prewashed with methanol with toluene - ethyl acetate - methanol - formic acid 8:6:4:1 in a saturated twin-trough chamber. Densitometric quantification at 285 and 298 nm.

J. Chromatogr. 445, 385-392 (1988). TLC on silica with hexane - ethyl acetate - acetone 5:4:1. Immersion for 10-20 s in a fluorogenic reagent containing 100 mL ethanol, 100 mL ether and 4 mL concentrated sulfuric acid. Development in the 2nd direction with hexane - ethyl acetate - dichloromethane 1:2:2. Detection under UV 366 nm. Detection limit, 0.5 µg for both.

J. Planar Chromatogr. 21, 107-112 (2008). Optimization and comparison of the acidic visualization methods most often used for steroids. OPLC of ethinyl estradiol, ’dienolether’ (3-methoxyestra-2,5(10)-dien-17b-ol), norethisterone, norethisterone acetate, norethisterone enanthate, nandrolone, and nandrolone decanoate on HPTLC silica gel with cyclohexanone - ethyl acetate - chloroform 1:1:1. Detection with sulfuric acid at three different concentrations, phosphomolybdic acid, and phosphoric acid with different heating temperatures for different times. Evaluation under UV 366 nm (sulfuric acid, phosphoric acid) and in white light (phosphomolybdic acid). It was found that derivatization at higher temperatures for shorter periods usually results in greater sensitivity, although heating for longer periods at lower temperatures leads to a more stable and robust result. Evaluation by videodensitometry.

J. Chinese Herb. Med. (Zhongcaoyao) 21, 297-299 (1990). TLC of the constituents in animal testes and in musk on silica with benzene – ethyl acetate 5:1, or hexane – ethyl acetate 9:1. Detection by spraying with diluted sulfuric acid and heating for 10 min at 105 °C. Comparison of the main constituents from two sources.

Asian J. Chem. 19(5), 3375-3381 (2007). The TLC method described in USP 28 does not separate all the related substances of alprazolam. An alternative HPTLC method is described for separation and estimation of starting material and synthesis related intermediates in alprazolam: 2-chloro acetamide-5-chloro benzophenone (impurity 1) i.e. starting material, nordiazepam (impurity 2), thionordiazepam (impurity 3), 2-(2-aceto hydrazinyl)-7-chloro-5-phenyl-3H-1, 4-benzodiazapine (impurity 4). The hRf values of alprazolam, impurity 4, impurity 3, impurity 2, and impurity 1 were 25, 16, 77, 45, and 83 respectively. The HPTLC method developed is capable of detecting impurities at a level of 0.05%.