Rev. Bras. Farmacogn. 23, 802-810 (2013). HPTLC of quercetin (1) and gallic acid (2) in Adiantum capillus-veneris on silica gel with toluene - ethyl acetate - formic acid 5:4:1. Quantitative determination by absorbance measurement at 254 nm. The hRF values for (1) and (2) were 53 and 84. Linearity was in the range of 200-1600 ng/zone for both (1) and (2).

CBS 112, 9-11 (2014). HPTLC of sibutramine on silica gel with toluene - methanol 9:1 with chamber saturation for 20 min, developing distance 70 mm. Quantitative absorbance measurement at 225 nm. A polynomial calibration curve was established in the working range of 78-3022 ng. Intermediate precision was between 2-9 %. The hRF of sibutramine was 53. The recoveries were between 96-104 %. For confirmation the sibutramine zone was eluted from the plate with the TLC-MS Interface and identified by MS. Among 52 tested commercial slimming products 26 were adulterated with sibutramine.

J. Liq. Chromatogr. Relat. Technol. 37, 1805-1818 (2014). HPTLC of azithromycin dehydrate (1) and cefixime trihydrate (2) on silica gel with methanol – ethyl acetate – toluene – ammonia (30 %) 45:35:20:4. Quantitative determination (A) by absorbance measurement at 366 nm or (B) after spraying with stannic chloride reagent (40 mL chloroform and 40 mL glacial acetic acid were mixed and 5 mL of stannic chloride was slowly added) or (C) ethanolic sulfuric acid (20 mL of concentrated sulfuric acid in 80 mL of ethanol) followed by absorbance measurement at 450 nm for (B) and (C). The hRF values for (1) and (2) were 80 and 27 for (A) and (B) and 67 and 30 for (C). Due to concentrated sulfuric acid, (C) showed a slight change in hRF. Linearity for (1) was in the range of 1000-5000 ng/zone (A), 1500-5000 ng/zone (B) and 1000-6000 ng/zone (C) and for (2) was 400-2000 ng/zone (A), 1600-4000 ng/zone (B) and 800-2400 ng/zone (C). The intermediate/inter-day/intra-day precision was below 2 % (n=3). The LOD and LOQ for (1) was 85 and 257 ng/zone (A), 119 and 360 ng/zone (B) and 39 and 119 ng/zone (C) and for (2) it was 36 and 110 ng/zone (A), 194 and 588 ng/zone (B) and 69 and 208 ng/zone (C), respectively. Recovery was in the range of 98.2-102.4 % for both (1) and (2).

Braz. J. Pharm. Sci. 49, 845-851 (2013). HPTLC of metoprolol (1) and hydrochlorothiazide (2) in human plasma on silica gel with chloroform - methanol - ammonia 18:2:1. Quantitative determination by absorbance measurement at 239 nm. The hRF values for (1) and (2) were 48 and 13. Linearity was in the range of 20-120 μg/zone for (1) and 2-12 μg/zone for (2). The intermediate/interday/intra-day precisions were below 5 % (n=3). The LOQs were 20 and 2 μg/zone for (1) and (2), respectively. Recoveries were between 70.6 and 84.9 %.

J. Ethnopharmacol. 156, 309-315 (2014). HPTLC of (1) phyllanthin and (2) ellagic acid in the whole plant of Phyllanthus rheedei on silica gel with toluene - ethyl acetate - formic acid 6:2:1, detection at UV 366 nm. The hRF values of (1) and (2) were 47 and 27, respectively. Fractions rich in phyllanthin and ellagic acid showed anti-HBV and hepatoprotective activity.

J. Planar Chromatogr. 27, 466-471 (2014). HPTLC of (1) flumethasone pivalate, (2) flumethasone, and (3) clioquinolon on silica gel with benzene – hexane – acetone – formic acid 500:400:200:13. Quantitative determination by absorbance measurement at 235 nm. The hRF values of (1) to (3) were 31, 7 and 64, respectively. Linearity was in the range of 30-400 ng/zone for (1), 50-300 ng/zone for (2) and 150-500 ng/zone (3). The intermediate precision was below 2 % (n=3) for (1) to (3). The LOD and LOQ were 9 and 27 ng/zone for (1), 13 and 39 ng/zone for (2) and 41 and 123 ng/zone for (3). Recoveries for (1) to (3) were in the range of 90-110 %. The method was statistically compared to a validated HPLC method.

J. Planar Chromatogr. 27, 372-376 (2014). For quality control, HPTLC of cefprozil monohydrate on silica gel with ethyl acetate – acetone – methanol – water – glacial acetic acid 15:5:5:3:1. Quantitative determination by absorbance measurement at 280 nm. The hRF value of cefprozil monohydrate was 20. Linearity was between 200 and 5000 ng/zone. The intermediate precision was below 1.5 % (n=3). The LOD and LOQ were 52 and 75 ng/zone, respectively. Recoveries were in the range of 98.7-101.2 %.

J. Planar Chromatogr. 28, 234-240 (2015). HPTLC of (1) omeprazole, (2) pantoprazole, (3) rabeprazole and (4) diclofenac from tablets on silica gel previously washed with methanol and activated at 105 °C for 20 min, with toluene - n-butanol - 25 % ammonia 30:70:2. Quantitative determination by absorbance measurement at 290 nm. The hRF values were 67 for (1), 38 for (2), 57 for (3) and 27 for (4). Linearity was between 50 and 500 ng/zone for (1), (2) and (3), and between 150 and 1500 ng/zone for (4). The interday and intraday precisions were below 2 %. The LOD and LOD respectively for (1) were 7 ng/zone and 24 ng/zone, for (2) 9 ng/zone and 30 ng/zone, for (3) 13 ng/zone and 43 ng/zone, and for (4) 25 ng/zone and 82 ng/zone. Recovery was 99.6 % for (1), 100.1 % for (2), 100.4 % for (3) and 100.1 % for (4).