J. Planar Chromatogr. 33, 169-177 (2020). HPTLC of berberine (1) and 5-fluorouracil (2) in rabbit plasma on silica gel with toluene - methanol - ethyl acetate - formic acid 6:2:6:1. Quantitative determination by absorbance measurement at 266 nm. The hRF values for (1) and (2) were 28 and 57, respectively. Linearity was between 20 and 300 ng/zone for both (1) and (2). Intermediate precisions were below 7 % (n=3). The LOQ was 29 ng/zone for (1) and 26 ng/zone for (2), respectively. Average recovery was 86.5 % for (1) and 87.2 % for (2).

J. Planar Chromatogr. 33, 131-139 (2020). HPTLC of arterolane maleate (1) and piperaquine phosphate (2) on silica gel with isopropyl alcohol - n-butanol - methanol - triethylamine 15:30:5:1. Quantitative determination by absorbance measurement at 232 nm. The hR_F values for (1) and (2) were 64 and 18, respectively. Linearity was 150-900 ng/zone for (1) and 750-4500 ng/zone for (2). Intermediate precisions were below 2 % (n=6). The LOD and LOQ were 6 and 18 mg/zone for (1) and 23 and 70 ng/zone for (2), respectively. Mean recovery rate was 98.9 and 103.9 % for (2).

J. Planar Chromatogr. 33, 51-57 (2020). HPTLCS (high-performance thin-layer chromatography scanning) of ethyl p-methoxycinnamate in the rhizome of Kaempferia galanga on silica gel with hexane - ethyl acetate 18:1. Quantitative determination by absorbance measurement at 309 nm. The hR_F value for ethyl p-methoxycinnamate was 29. Linearity was between 2 and 6 ng/zone. Intermediate precisions were below 2.4 % (n=3). Mean recovery rate was 100.1 %. Results were compared with a validated HPLC method and the HPTLCS method was more environmetnally friendly..

J. Planar Chromatogr. 33, 71-77 (2020). HPTLC of ledipasvir (1) and sofosbuvir (2) on silica gel with ethyl acetate - hexane - methanol  32:5:3. Quantitative determination by absorbance measurement at 256 nm. Linearity was between 60 and 1980 ng/zone for (1) and 45 and 3600 ng/zone for (2). Intermediate precisions were below 2 % (n=3). The LOD and LOQ were 16 and 50 ng/zone for (1) and 13 and 40 ng/zone for (2), respectively. Mean recovery rate was 99.4 % for both (1) and (2).

J. Planar Chromatogr. 33, 79-87 (2020). HPTLC of velpatasvir (1) and sofosbuvir (2) on silica gel with chloroform - methanol 19:1. Quantitative determination by absorbance measurement at 265 nm. The hR_F values for (1) and (2) were 29 and 19, respectively. Linearity was between 5 and 50 µg/zone for (1) and 10 and 70 µg/zone for (2).  Intermediate precisions were below 2 % (n=3). The LOD and LOQ were 3 and 5 µg/zone for (1) and 8 and 10 µg/zone for (2), respectively. Mean recovery rate was 100.2 % for (1) and 100.9 % for (2).

J. Planar Chromatogr. 33, 59-70 (2020). HPTLC of metformin (1), saxagliptin (2) and dapagliflozin (3) on silica gel with chloroform - methanol - water - acetic acid 740:260:50:1. Quantitative determination by absorbance measurement at 224 nm. The hR_F values for (1) to (3) were 14, 50 and 66, respectively. Linearity was between 30 and 350 µg/mL for (1), 140 and 1500 µg/mL for (2) and 50 and 600 µg/mL for (3).  Intermediate precisions were below 2 % (n=6). LOD and LOQ were 7 and 23 µg/mL for (1), 39 and 130 µg/mL for (2) and 14 and 47 µg/mL for (3), respectively. Recovery rate was between 98.9 and 100.5 % for (1), 99.2 and 100.5 % for (2) and 99.2 and 100.7 % for (3). Comparable results were obtained when compared with a HPLC method.

J. of Chromatogr. Sci. 57 (8), 688 - 696 (2019). Tephrosia purpurea (L.) Pers., commonly known as “wild indigo”, is used in TCM to treat liver, spleen and kidney disorders. To investigate the seasonal effect on the quantity of its phytoconstituents lupeol, β-sitosterol and rotenone, analysis of the extracts from plant material collected in different seasons by HPTLC on silica gel with toluene - ethyl acetate - formic acid 9:1:1. The zones due to  β-sitosterol, rotenone and lupeol were observed at hRF 38, 45 and 52, respectively. Validation of the method in terms of precision, repeatability, specificity, sensitivity, linearity and robustness. The quantitative results obtained with this method showed that the content of these phytoconstituents varies from season to season. It was found that T. purpurea should not be collected in winter season for the preparation of therapeutic formulations because of the high content of rotenone, which is responsible for Parkinson’s disease and associated with heart failure, fatty liver and liver necrosis.

J. of Modern Trad. Chinese Med. 20 (7), 821-824 (2018). Mulusin, a class of isoprene flavonoids extracted from Mori Cortex, has anti-tumor, anti-inflammatory, hypoglycemic, hypolipidemic, analgesic, anti-spasm, and cholinesterase restricting activity. For quality control, TLC of mulusin on silica gel with petroleum ether - dichloromethane - ethyl acetate 15:8:10 at 25 ± 0.3 ˚C with chamber saturation for 30 min. Detection at UV 254 nm. The hRF of mulusin standard was 43. Quantitative absorbtion measurement of morusin by densitometry at 273 nm. Linearity was in the range of 200 - 1100 ng/zone (r=0.999), precision on one plate was RSD = 1.21 % (n=6) and on plate-to-plate RSD = 2.30 % (n=6). Recovery from standard sample addition was 99.2 % (RSD = 1.51, n = 6). The LOD was 20 ng/zone and LOQ 40 ng/zone.