J. Chromatogr. Sci. 60 (3), 267-273 (2022). HPTLC for the selective detection of the diuretic drug triamterene in pure form, tablets and human plasma, on silica gel with ethyl acetate - dimethylformamide - ammonia 70:27:3. Quantitative determination by fluorescence measurement at 440 nm improved the method sensitivity 250-fold compared with previously reported studies, and enabled the detection of triamterene in the linear concentration range of 0.8 to 60 ng/band for the pure drug and 1.0 to 60 ng/band for biological samples (human plasma).

J. Planar Chromatogr. 35, 73-81 (2022). HPTLC of omeprazole (1) and its impurity 4‑methoxy‑2‑nitroaniline (1) on silica gel with methanol - n-hexane - ethyl acetate 1:10:11. Quantitative determination by absorbance measurement at 291 and 223 nm for (1) and (2), respectively. The hRF values for (1) and (2) were 25 and 89, respectively. Linearity was between 100 and 500 ng/zone for (1) and 10 and 50 ng/zone for (2). Interday and intra-day precisions were below 1 % (n=3). The LOD and LOQ were 3.2 and 9.8 ng/zone for (1) and 0.41 and 1.25 ng/zone for (2), respectively. Recovery was in the range of 98-102 % for (2).

J. Planar Chromatogr. 34, 455-466 (2021). HPTLC of mometasone furoate (1) and salicylic acid (2) on silica gel with chloroform - ethanol 9:1. Quantitative determination by absorbance measurement at 250 nm for (1) and 300 nm for (2). The hRF values for (1) and (2) were 13 and 93, respectively. Linearity was between 100 and 1600 ng/zone for (1) and 400 and 5000 ng/zone for (2). LOD and LOQ were 16 and 47 ng/zone for (1) and 7 and 20 ng/zone for (2), respectively. Intermediate precisions were below 2 %. Recovery was between 98 and 102 %.

J. Planar Chromatogr. 34, 467-477 (2021). HPTLC of five antihypertensive drugs, atenolol (1), amlodipine (2), losartan (3), hydrochlorothiazide (4), and telmisartan (5) on silica gel with chloroform - toluene - methanol - acetone - formic acid 400:300:150:260:3. Quantitative determination by absorbance measurement at 254 nm. The hRF values for (1) to (5) were 7, 12, 45, 56 and 64, respectively. Linearity ranged from 1-25 μg/zone for (1), (3) and (5) and 1-20 μg/zone for (2) and (4). LOD and LOQ were 300 and 900 ng/zone for (1), 130 and 420 ng/zone for (2), 230 and 690 ng/zone for (3), 140 and 430 ng/zone for (4) and 190 and 560 ng/zone for (5). Intermediate precisions were below 1 % (n=9). Mean recovery was 99.3 % fo (1), 100.1 % for (2), 99.7 % for (3), 99.7 % for (4) and 100.3 % for (5).

J. Planar Chromatogr. 34, 337-343 (2021). HPTLC of montelukast (1) and bilastine (2) on silica gel with acetonitrile - ethyl acetate - ammonia 40:60:1. Quantitative determination by absorbance measurement at 282 nm. The hRF values for (1) and (2) were 53 and 27, respectively. Linearity was between 100 and 500 ng/zone for (1) and 200 and 1000 ng/zone for (2). LOD and LOQ were 13 and 40 ng/zone for (1) and 65 and 198 ng/zone for (2). Intermediate precisions were below 2 % (n=3). Recovery was between 98.0 and 99.7 % for (1) and 98.0 and 99.0 % for (2).

J. Planar Chromatogr. 34, 263-270 (2021). HPTLC of quetiapine fumarate (1) and its related genotoxic impurities 2-chloroaniline (2) and 2-aminodiphenylsulide (3) on silica gel with ethyl acetate - ethanol - n-heptane 5:1:4. Quantitative determination by absorbance measurement at 229 nm. The hRF values for (1) to (3) were 13, 57 and 76, respectively. Linearity was between 100 and 600 ng/zone for (1) and 10 and 60 ng/zone for (2) and (3). Intermediate precisions were below 2 %. The LOD and LOQ were 0.9 and 2.8 ng/zone for (1), 0.3 and 0.9 ng/zone for (2) and 0.2 and 0.5 ng/zone for (3), respectively. Recovery of the impurity in quetiapine fumarate ranged between 99 % and 101 %.

J. Planar Chromatogr. 34, 197-202 (2021). HPTLC of L‑proline (1) and L‑lysine (2) derivatives on silica gel with ethanol - toluene 2:3 in a horizontal chamber. Amino acids pre-chromatographic derivatization with 2-propanol - phenyl isothiocyanate - phosphate buffer pH 12 7:1:1. Detection by spraying with a solution of 4 % sodium azide, 0.5 % starch, pH 5.5, followed by exposure to iodine vapor for 20 s. Plates were scanned with an office scanner and the zones were converted to peaks by software. The hRF values for (1) and (2) were 32 and 67, respectively. Intermediate precisions were below 9 % (n=6). The LOD was 0.05 nmol/zone for (1) and 0.05 nmol/zone for (2). Recovery was between 94 and 104 % for (1) and 82 and 104 % for (2).

J. Planar Chromatogr. 34, 229-242 (2021). HPTLC of chlorthalidone (1) and metoprolol succinate (2) on silica gel with toluene - methanol - triethylamine 16:4:1. Quantitative determination by absorbance measurement at 230 nm. The hRF values for (1) and (2) were 44 and 23. Linearity was between 200 and 1000 ng/zone for (1) and 800 and 4000 ng/zone for (2). Intermediate precisions were below 2 %. The LOD and LOQ were 29 and 88 ng/zone for (1) and 151 and 459 ng/zone for (2), respectively. Recovery was between 99.9 and 100.9 % for (1) and 100.4 and 101.6 % for (2).