J. Planar Chromatogr. 27, 1999-2020 (2014). HPTLC of methocarbamol in pharmaceutical mixtures with ibuprofen, paracetamol and diclofenac sodium and in the presence of its degradation product guaifenesin on silica gel with chloroform - methanol 47:3. Quantitative determination by absorbance measurement at 264 nm. A chemometric handling of the TLC peak responses involving the convolution of the derivative curves using 8-points sin x i polynomials, allowed the analysis of different mixtures of methocarbamol with enhancing of the regression parameters.

J. Planar Chromatogr. 27, 120-123 (2014). HPTLC of azathioprine on silica gel with methanol - toluene - 25 % ammonia 70:30:1. Quantitative determination by absorbance measurement at 285 nm. The hRf value for azathioprine was 63. Linearity was in the range of 20-120 ng/zone. The intermediate/interday/intra-day precisions were below 1 % (n=6). The LOD and LOQ were 6 and 20 ng/zone, respectively. Average recovery was 98.7 %.

J. Planar Chromatogr. 27, 217-229 (2014). HPTLC of omeprazole (1), panoprazole (2), rabeprazole (3), and lansoprazole (4) in binary mixtures with domperidone (5) (method A) and ternary mixture containing omeprazole (1), tinidazole (6), and clarithromycin (7) (method B) on silica gel with ethyl acetate - methanol - benzene - acetonitrile 5:4:8:3 for (A) and chloroform - n-hexane - methanol 3:4:1 for (B). Quantitative determination by absorbance measurement at 293 nm for (1)/(5) and (3)/(5), 286 nm for (4)/(5), 287 nm for (2)/(5), and 310 nm for (1)/(6)/(7). The hRF values for (1) to (5) in (A) were 54, 55, 55, 60 and 33, respectively, and for (1), (6) and (7) in (B) were 68, 22 and 48, respectively. Linearities for (1) to (7) were in the range of 240-1440 ng/zone, 180-1080 ng/zone, 240-1440 ng/zone, 240-1440 ng/zone, 120-720 ng/zone, 30-180 ng/zone and 2250-6000 ng/zone, respectively. The intermediate/interday/intra-day precisions were below 4 % (n=6). Recoveries ranged from 98.1 to 103.1 % for (1) to (7).

J. Planar Chromatogr. 27, 2942-2955 (2014). HPTLC of propafenone hydrochloride in tablets on silica gel with chloroform - methanol - acetic acid 79:20:1. Quantitative determination by absorbance measurement at 316 nm. The hRF value for propafenone hydrochloride was 64. Linearity was in the range of 100-3200 ng/zone. The intermediate/interday/intra-day precisions were below 2 % (n=3). The LODs and LOQs were 20 and 80 ng/zone, respectively. Recoveries were between 99.5 and 102.2 %.

Chinese J. of Forestry Science 49 (10), 127-134 (2013). Flavonoids in bamboo leaves have free radical scavenging, antioxidant, anti-aging, antibacterial, and anti-inflammatory effects and are used as a component in TCM for regulating blood fat and preventing cardiovascular and cerebrovascular diseases. Bamboo-leaf flavonoids are also used in cosmetics and as feed additive. In order to choose the best bamboo species for extraction of flavonoids and to set up a quality control method, the flavonoids in eleven samples of bamboo leaves of three genera collected from Yunnan, Fujian, Sichuan, Jiangsu and Jiangxi provinces are studied by HPTLC. HPTLC-AMD of sample extracts and the standards isoorientin, orientin, isovitexin, vitexin and tricin on silica gel, cleaned with methanol and methylene chloride and dried at 105 °C, with methanol – ethyl acetate – methylene – formic acid 4:7:9:2 to 50 mm in the first step, with acetone – methanol - ethyl acetate – methylene chloride – formic acid 1:2:7:10:2 to 75 mm in the second step, and with acetone - methanol - ethyl acetate - methylene chloride – formic acid 2:1:6:11:2 to 90 mm in the third step. Detection under UV 366 nm after spraying with 1 % aluminum trichloride in ethanol. Quantification of the flavonoids by densitometry at UV 366 nm via peak area. The quantitative method for different flavonoids was validated by investigation of the linearity (90-1750 ng/zone), the precision (%RSD=1.0-2.0 %, n=3 intra-day; %RSD=0.9-2.0 %, n=3 inter-day), and the repeatability (%RSD=0.9-1.9 %, n=9). The LODs were 25-40 ng/zone, and the recoveries were 81.3-106.9 % (n=3).

J. Planar Chromatogr. 28, 24-29 (2015). HPTLC of new derivatives of 1,2,4-triazole and thiosemicarbazide on RP-18W with 30 % acetonitrile and 40 % MeOH as organic modifiers, both in water, detection at UV 254 nm. 30 % provided the most close phase ratio in TLC and HPLC. The method can be used as a pilot technique for the anticipation of retention in HPLC.

J. Planar Chromatogr. 27, 472-476 (2014). HPTLC of (1) genistein and (2) vitexin in seeds of Vigna mungo on silica gel with toluene – ethyl acetate – methanol – acetic acid – formic acid 6:14:2:1:1 after saturation with mobile phase for 25 min. Quantitative determination by absorbance measurement at 254 nm. The hRF values of (1) and (2) were 81 and 31, respectively. Linearities were in the range of 500-2500 ng/zone for (1) and (2). The intermediate precisions were below 8 % (n=6) for (1) and (2). The LOD and LOQ were 14 and 42 ng for (1) and 52 and 159 ng for (2), respectively. Recoveries for (1) and (2) were in the range of 96.1-97.1 and 95.7-97.6 %.

J. Planar Chromatogr. 27, 333-339 (2014). TLC of alkaloids such as (1) papverine, (2) quinine, (3) berberine, (4) brucine, (5) emetine, (6) chelidonine, (7) boldine, (8) protopine and (9) allocryptopine on CN or RP18W phase with mixture of acetonitrile and water containing: acetic buffer at pH 3.6, 1 % acetic acid, 1 % ammonia, 0.01 M octane sulfonic acid sodium salt or methanol, and water containing 0.01 M diethylamine. On C18 plates, the best conditions for the separation of alkaloids were obtained with the mobile phase containing addition of octane sulfonic acid sodium salt, diethylamine, or aqueous ammonia; as for the CN plates, with aqueous eluents containing diethylamine or ammonia and nonaqueous eluent containing mixture of methanol, diidopropyl ether, and 2% ammonia. The efficiency of the system was increased by using a combination of two-dimensional thin-layer chromatography with multiple development chromatogram methods.