International Journal of PharmaTech Research 3(2), 1179-1185 (2011). TLC of gatifloxacin on silica gel with toluene - acetic acid - triethylamine 8:5:1. The hRf value was 46. Quantitative determination at 288 nm. The method was found to be linear in the range of 200-400 ng/band with a mean recovery of 99.9 %. The drug was subjected to different stress conditions (acid, base, thermal, photolytic, oxidative) and the degradation products were well resolved from the main drug.

Journal of Pharmacy Research 4(3), 643-644 (2011) TLC of doxofylline on silica gel with acetonitrile - methanol 7:3. The hRf of doxofylline was 66. Quantitative determination at 208 nm. The method was found to be linear in the range of 100-600 ng/band with an average recovery of 99.7 %. The results by TLC were comparable with results obtained by RP-HPLC.

J. Planar Chromatogr. 24, 48-52 (2011). HPTLC of hydroquinone on silica gel with chloroform - methanol 17:3 in a twin-trough chamber after saturation for 30 min at 25 °C. Quantitative determination by densitometry in absorbance mode at 289 nm. The hRf of hydroquinone was 51. Linearity was between 100 and 2500 ng/zone. Mean recovery was 99.2 %, with %RSD between 1.7-2.0 %. The intra-day precision (n = 3) as %RSD was 0.9-1.1 % and the inter-day precision 1.0-1.2 %. The LOD and LOQ was 39 and 116 ng/band, respectively.

f. ) Etting, (Loranthaceae), growing on different substrates. J. Planar Chromatogr. 24, 60-65 (2011). HPTLC of phenolic compounds with caffeic acid, (+)-epicatechin, ellagic acid, gallic acid, and kaempferol as markers on silica gel with toluene - ethyl acetate - methanol - formic acid 14:6:1:1 in a twin-trough chamber with saturation for 30 min at 24 °C. Quantitative determination by absorbance measurement at 300 nm. Detection by dipping in anisaldehyde-sulfuric acid reagent followed by heating at 110 °C for 5 min. Evaluation under UV 254 nm and visible light after derivatization. Repeatability (n = 7) was between 0.5-2.4 %; intermediate precision was between 1.5-4.4 %. For (+)-epicatechin, ellagic acid, gallic acid, caffeic acid, and kaempferol, LOD was 332, 225, 21, 64, and 35 ng/zone, LOQ was 1157, 740, 67, 242, and 115 ng/zone, and precision (%RSD) was 3.8, 4.9, 4.7, 5.4, 1.7 %, respectively. The hRf value was 39 for (+)-epicatechin, 43 for ellagic acid, 55 for gallic acid, 65 for caffeic acid, and 72 for kaempferol.

J. Planar Chromatogr. 24, 242-247 (2011). HPTLC of E-guggulsterone (EG), Z-guggulsterone (ZG), 11-keto-ß-boswellic acid (11-KBA), and 3-acetyl-11-keto-ß-boswellic acid (A-11-KBA) in pharmaceutical formulation on silica gel with n-hexane - chloroform - ethyl acetate - methanol 10:3:3:1 in a twin-trough chamber with saturation for 15 min at room temperature (25 +/- 2 °C) and relative humidity of 60 +/- 5 %. Quantitative determination by densitometry in absorbance mode at 254 nm. The hRf values were 28, 39, 61, 68 for 11-KBA, A-11-KBA, EG, and ZG, respectively. The linearity range was 10-90 ng/band for EG and ZG, and 50-450 ng/band for 11-KBA and A-11-KBA. The repeatability of measurement of peak area and of sample application (%RSD) were 1.1 and 1.3 % for EG, 1.4 and 1.5 % for ZG, 0.5 and 1.1 % for 11-KBA, and 1.1 and 1.1 % for A-11-KBA, respectively. The mean intra-day and inter-day precsions (%RSD) were 1.0 and 1.1 % for EG, 1.1 and 0.9 % for ZG, 0.7 and 0.8 % for 11-KBA, and 1.1 and 1.3 for A-11-KBA. The method precisions (%RSD) were 1.3, 1.3, 1.1, and 1.3 % and the recoveries (by standard addition) were 96.9, 97.4, 97.6 and 97.2 % for EG, ZG, 11-KBA and A-11-KBA, respectively.

J. Chromatogr. A 1232, 3-18 (2012). A review on overpressured-layer chromatography (OPLC). OPLC is a separation technique that combines the advantages of conventional TLC/HPTLC with those of HPLC. Use of a special chromatoplate and a pump to increase and optimize the mobile phase flow velocity through an optional development distance in an adsorbent layer by employing the pressurized ultramicro (UM) chamber as a closed adsorbent layer chamber. Description of the versions of OPLC instruments, the character and achievement of off-line and on-line OPLC systems in analytical and preparative use. Demonstration of the unique advantages of planar-layer systems for detection, isolation and identification of new antimicrobials, antineoplastics, biopesticides and other biologically active substances as well as for studying fundamental biochemical reactions and mechanisms by BioArena which was newly developed as a complex bioautographic system.

J. Planar Chromatogr. 25, 388-393 (2012). HPTLC of alternariol (1), alternariol monomethyl ether (2), altenuene (3), L-tenuazonic acid (4) in Alternaria alternata strains isolated from foodstuffs on silica gel pre-coated with oxalic acid in methanol with toluene - ethyl acetate - formic acid 6:3:1. Quantitative determination by absorbance measurement at 254 nm. The hRf values of compounds (1) to (4) were 25, 36, 49 and 30, respectively. The %RSD of repeatability were 7–19. Limit of detection for compounds (1) to (3) was 0.3 mg/kg and limit of quantification for (1) to (4) was 5.0 mg/kg in rice cultures with Alternaria alternata mycelium.

J. Planar Chromatogr. 25, 475-480 (2012). HPTLC of amlodipine besylate (1), hydrochlorothiazide (2) and olmesartan medoxomil (3) on silica gel with chloroform - ethyl acetate - toluene - methanol - glacial acetic acid 39:39:77:39:6. Quantitative determination by absorbance measurement at 230 nm. The hRf of compounds (1) to (3) were 31, 56 and 81, respectively. Linearity was in the range of 200-4800 ng/band for (1), 100-4000 ng/band for (2) and 200-5200 ng/band for (3). Limits of detection and quantification were 35 and 101 ng/band for (1), 20 and 59 ng/band for (2) and 48 and 144 ng/band for (2), respectively. Intermediate/inter-day/intra-day precision was below 1.0 % (n=6). Mean recovery was between 100.0 and 100.3 % for all active agents.