Planta Med. 76, 474-480 (2010). HPTLC of camptothecin and plant material extracts (roots, stems, leaves,and fruits) on silica gel with chloroform - ethyl acetate - methanol 9:10:1 in a twin trough chamber at 25 +/- 2°C and 40 % relative humidity. Quantitative determination by densitometry at 360 nm. Linearity was between 80 and 480 ng/zone with a correlation coefficient of 0.998 +/- 0.020. Instrumental precision (%RSD) was 0.5 %. Repeatability (%RSD) of sample and standard were 1.1 and 1.0 %. The LOD and LOQ were found to be 40 and 80 ng/zone, respectively. The accuracy of the method was proven by the average percentage recovery of 99.1 %.

J. Planar Chromatogr. 24, 44-47 (2011). HPTLC of nitrazepam on silica gel with benzene - ethanol 5:1 in a horizontal chamber with saturation for 50 min. Quantitative determination by densitometry in absorbance mode at 196 nm. The hRf of nitrazepam was 68. Linearity was in the range of 0.25-10.0 µg/zone. Mean recovery was 98.8 % and 98.8 % for tablet and pure powder, respectively. Precision and accuracy (%RSD) were 1.3 % and 1.2 %, respectively. LOD and LOQ were 0.49 and 1.52 µg/mL, respectively.

J. Planar Chromatogr. 25, 77-80 (2012). HPTLC of gemcitabine on silica gel with toluene - methanol - chloroform 6:6:5. Quantitative determination by absorbance measurement at 268 nm. The hRf value of gemcitabine was 48. Linearity was in the range of 500-3000 ng/band. Intraday and interday precisions (%RSD) were 1.4-1.6 % and 1.6-1.8 %, respectively. Recovery was found to be in the range of 98.3-101.8 %.

J. Planar Chromatogr. 25, 368-373 (2012). HPTLC of rebamipide on silica gel with toluene - methanol - triethylamine 16:9:1. Quantitative determination by absorbance measurement at 230 nm. The hRf of rebamipide was 59. Linearity was in the range of 100-600 ng/band. Limits of detection and quantification were 6 and 18 ng/band, respectively. Intermediate intra-day/inter-day precision was below 1.7 % (n=3). Recovery (by standard addition) was between 100.1 and 100.9 %. The proposed HPTLC method is equivalent to a reported HPLC method.

J. Liq. Chromatogr. Relat. Technol. 36, 2446-2462 (2013). HPTLC of amitriptyline in tablets on silica gel with acetone - ammonium hydroxide 99:1. Quantitative determination by absorbance measurement at 254 nm. The hRf value of amitriptyline was 46. Linearity was 0.70-1.30 µg/zone. The earlier model TLC to HPTLC-densitometry transfer procedure was expanded by adding sample peak identification confirmation and peak purity (specificity) tests.

Trends in Chromatography 8, 131-135 (2013). Based on the Minilab TLC screening methods two individual and one simultaneous HPTLC methods for quantification of lumefantrine and artemether were developed. HPTLC of artemether, lumefantrine, and both substances in a combined tablet formulation on silica gel with ethyl acetate - glacial acetic acid - toluene 2:1:9 with chamber saturation. Quantitative absorbance measurement of lumefantrine at 254 nm. For artemether, detection by spraying with methanol - 96 % sulfuric acid 19:1 and heating at 100 °C for 5 minutes, evaluation in daylight and quantitative absorbance measurement at 610 nm. With the simultaneous method artemether zones were detected by heating at 160 °C for 5 min, and after cooling absorbance measurement at 254 nm was performed. This is a novel, reagent-free detection method based on thermochemical activation of fluorescence quenching. Precision (%RSD) for the artemether individual method was 0.1-0.6 % and recovery 98-103 %. Precision (%RSD) for the lumefantrine individual method was 0.9-1.8 % and recovery 100-102 %. With the simultaneous method the hRF was 34 for lumefantrine and 61 for artemether, precision (%RSD) was below 3 % and recovery was 98-100 %.

J. Liq. Chromatogr. Relat. Technol. 38, 1121-1125 (2015). HPTLC of moxonidine and impurities (1) to (4) in dosage forms on silica gel with methanol - toluene - dichloromethane - ammonia 20:30:20:1. Quantitative determination by absorbance measurement at 260 and 280 nm. Average migration distances for moxonidine and its impurities (1) to (4) were 58.5 mm, 64.4 mm, 34.5 mm, 16.1 mm and 25.6 mm, respectively. Linearity was in the range of 200-600 ng/zone for moxonidine and 20-200 ng/zone for impurities (1) to (4). LOD and LOQ for impurities (1) to (4) were 7 and 20 ng/zone. The intermediate precisions were below 4 % (n=6). Recoveries ranged between 90 and 108 %.

J. Planar Chromatogr. 29, 195-202 (2016). HPTLC of naftopidil on silica gel with toluene – ethyl acetate – methanol – triethylamine 80:20:5:3. Quantitative determination by absorbance measurement at 254 nm. The hRF value was 52. Linearity was in the range of 500-2500 ng/zone. Intermediate precisions were below 1.5 %. The LOD and LOQ were 95 and 268 ng/zone. Average recovery was 100.0%.