J. Liq. Chromatogr. Relat. Technol. 35, 524-532 (2012). HPTLC of atorvastatin calcium (1), ezetimibe (2), and fenofibrate (3) in tablet on silica gel with toluene – chloroform – methanol 23:15:7 + 1 drop glacial acetic acid. Quantitative determination by absorbance measurement at 253 nm. The hRf values of active agents (1) - (3) were 20, 33 and 80, respectively. Linearity was 200-800 ng/zone for (1) and (2) and 4-16 µg/zone for (3). The intermediate/inter-day/intra-day precision was below 1.1 % for (1), 1.3 % for (2) and 1.5 % for (3) (n=6). The limits of detection and quantification were 19 and 59 ng/zone for (1), 23 and 68 ng/zone for (2), and 1449 and 4390 ng/zone for (3), respectively. Recovery (by standard addition) was between 99.1 and 99.8 % for compounds (1) to (3).

J. Planar Chromatogr. 26, 86-92 (2013). HPTLC of carteolol on silica gel with chloroform - methanol 5:1. Quantitative determination by absorbance measurement at 254 nm. The hRf of carteolol was 31. Linearity was in the range of 200-1200 ng/zone. LOD and LOQ were 34 ng/zone and 104 ng/zone, respectively. Intermediate precision was below 2 %. The method could effectively separate the drug from its degradation products.

J. Planar Chromatogr. 25, 133-137 (2012). HPTLC of thiocolchicoside (1) and aceclofenac (2) in combined dosage form on silica gel with methanol - chloroform - water 48:1:1. Quantitative determination by absorbance measurement at 254 nm. The hRf values of (1) and (2) were found to be 70 and 83, respectively. Linearity was in the range of 30-180 ng/band for (1) and 750-4500 ng/band for (2). Recovery was in the range of 98.7-101.2 % for both.

J. Planar Chromatogr. 27, 58-65 (2014). HPTLC of ternary mixtures of cetirizine dihydrochloride (1), pseudoephedrine (2), and/or phenylpropanolamine (3) and paracetamol (4) on silica gel with methanol - water 199:1. Quantitative determination by absorbance measurement at 257 nm. The hRF values for compounds (1) to (4) were 66, 16, 23 and 83, respectively. Linearity was in the range of 1-4 µg/zone for (1), 3-10 µg/zone for (2), 4-8 µg/zone for (3) and 5-100 µg/zone for (4), respectively. The intermediate/interday/intra-day precisions were below 2 % (n=5). The LOD and LOQ were 0.3 and 1 µg/zone for (1), 0.9 and 3 µg/zone for (2), 1.2 and 4 µg/zone for (3) and 1.5 and 5 µg/zone for (4), respectively. Mean recoveries for (1) to (4) were close to 100 %.

J. AOAC Int. 98, 1226-1233 (2015). HPTLC of three phosphodiesterase type 5 inhibitors, sildenafil (1), vardenafil (2), and tadalafil (3), and eight of their analogs, hydroxyacetildenafil (4), homosildenafil (5), thiohomosildenafil (6), acetildenafil (7), acetaminotadalafil (8), propoxyphenyl (9), hydroxyhomosildenafil (10), hydroxyhomosildenafil (11) and hydroxythiohomosildenafil (12) in finished products on silica gel with TBME - methanol - ammonia 28% 20:2:1. Detection under 254 and 366 nm UV light and by absorbance measurement at 232 nm. LOD was 30 ng/zone for all substances. Confirmation by HPTLC-ESI-MS. The method was successfully_x000D_ applied to screening of 45 commercial lifestyle products. Of those, 31 products tested positive for at least one illegal component (sildenafil, tadalafil, propoxyphenyl, hydroxyhomosildenafil, or dimethylsildenafil).

J. Planar Chromatogr. 29, 453-461 (2016). HPTLC of chlorzoxazone (1) and diclofenac potassium (2) in the presence of the nephrotoxic chlorzoxazone degradation product_x000D_
2-amino-4-chlorophenol (3) on silica gel with chloroform ‒ ethanol ‒ triethylamine 90:10:1. Quantitative determination by absorbance measurement at 230 nm. The hRF values for (1) to (3) were 63, 35 and 42, respectively. Linearities ranged between 1.5-5 μg/zone for (1), 0.5-4 μg/zone for (2) and 0.4-4 μg/zone for (3). The intermediate precisions were below 1.3 % (n=3). The LODs and LOQs were 320 and 980 ng/zone for (1), 140 and 450 ng/zone for (2) and 120 and 370 ng/zone for (3), respectively. Average recoveries were 100.2 % for (1), 99.3 % for (2) and 99.4 % for (3).

J. Planar Chromatogr. 30, 363-374 (2017). HPTLC of acetylsalicylic acid (1) and its related compound salicylic acid (2) on silica gel with n-hexane – diethyl ether – 80 % acetic acid 7:2:1. Good quality densitograms with well separated and symmetric peaks of (1) and (2) were achieved. Detection with the following reagents: Janus blue, bromophenol blue, bromocresol blue, hydrogen peroxide (without heating and with heating to 90 °C during 60 min), 1 % sodium hydroxide (with heating to 45 °C and also with heating to 90 °C during 60 min), brilliant green, malachite green, and thymol blue.

J. Planar Chromatogr. 31, 489-495 (2018). HPTLC of abacavir sulfate (1), lamivudine hydrochloride (2), and dolutegravir sodium (3) on silica gel with ethyl acetate ‒ ethanol ‒ acetone ‒ ammonia 2239:370:250:75. A factorial design was utilized to aid in method development and optimization. Quantitative determination by absorbance measurement at 267 nm. The hRF values for (1) to (3) were 65, 34 and 26, respectively. Linearity ranged between 4.8-14.4 μg/zone for (1), 2.4-7.2 μg/zone for (2) and 0.4-1.2 μg/zone for (3). LOD and LOQ were 997 ng/zone and 3022 ng/zone for (1), 254 ng/zone and 771 ng/zone for (2), and 100 ng/zone and 304 ng/zone for (3), respectively. The intermediate precision was <2 % (n=3). Recoveries were found in the range of 98.1–101.0 % for (1), 98.3–100.00 % for (2), and 98.5–101.3 % for (3), respectively._x000D_