J. Chromatogr. A 1217 (23), 4868-4872 (2010). Comparison of the kinetic performance, measured by plate height, of high-performance thin-layer chromatography (HPTLC), high-performance liquid chromatography (HPLC) and pressurized planar electrochromatography (PPEC). HPTLC on RP18W with mobile phases composed of acetonitrile - buffer. The HPLC column was packed with the same adsorbent, which was scrapped from an RP18W HPTLC plate. An additional HPLC column was packed with C18-type silica based (LiChrosorb RP18) adsorbent of 5 µm particle diameter. The plate height of both HPLC and PPEC systems depends on the flow velocity and the migration distance of the mobile phase. As test solution prednisolone succinate was used. The best performance was obtained by the PPEC system. The separation efficiency of the systems was investigated and confirmed by use of a test component mixture composed of six hormones.

J. Planar Chromatogr. 23, 50-55 (2010). HPTLC of andrographolide on silica gel with chloroform - methanol - ethyl acetate 12:3:2 in a twin-trough chamber previously saturated for 15 min. Quantitative determination by absorbance measurement at 223 nm. The relative standard deviation of intra-day and inter-day analysis was in the range of 0.56-1.33 %. Lineartiy was given between 200-700 ng/band; the correlation coefficient was 0.9998 and the RSD 0.97 %. The limits of detection and quantification were 60 and 150 ng/band. Average recovery was 98.8 +- 0.41 %.

Abstract No. F-10, 61st IPC (2009). HPTLC of Embella ribes Churna formulation on silica gel with chloroform - ethyl acetate - formic acid 5:4:1 in a twin trough chamber. Densitometric measurement of embelin at 291 nm. The method was linear in the range of 600-1800 ng/band with recovery value of 99.1-101.2 %. The formulation was also analyzed by HPLC and results were found to be comparable.

Abstract No. C-161, 61st IPC (2009). An HPTLC method is reported for estimation of andrographolides bitter principles in Andrographis paniculata, popularly known as kalmegh. HPTLC of methanolic and water extracts on silica gel with chloroform - methanol 7:1 in a saturated twin trough chamber. Quantitative evaluation by absorbance measurement at 231 nm. The method was found to be linear in the range of 1-5 µg/band. Both extracts were found to contain andrographolides. Maximum yields of andrographolides were observed in extracts prepared by refluxing.

J. Planar Chromatogr. 23, 70-74 (2010). Descripton of a selective and simple HPTLC method for quantification of oenothein B on the basis of the free gallic acid and total gallic acid content after acid hydrolysis. HPTLC of gallic acid on silica gel with benzene - methanol - acetic acid 90:16:8 in a glass chamber previously saturated with the mobile phase vapor for 20 min. Quantitative determination by absorbance measurement at 570 nm after derivatization with 1 % ethanolic iron(III) chloride solution. Average recovery of the active ingredient was in the range 95.4-104.6 %. Linearity was in the range of 440-2200 ng/band. The correlation coefficient r was 0.9991, LOD/LOQ were120/360 ng/band; repeatability (RSD) was 3.0 % and intermediate precision 1.0 %; intraday precision (RSD, n = 6, 440-2200 ng/band) was 3.8 to 5.2 % and interday precision 4.3 to 5.7 %. Both, precision and accuracy, were within acceptable limits for routine drug analysis (</= 15 %).

Encyclopedia of Chromatography Third Edition 1, 2319-2322 (2009). The author describes the techniques and instruments for the detection and quantification of radiolabeled substances in thin-layer radiochromatography (TLRC) or radio-TLC. In detail, film autoradiography, liquid scintillation counting (LSC), storage phosphor imaging and in situ radioactivity scanning are described. The instruments for these methods are highly automated providing significant advantages in radiopharmaceutical purity determination, metabolism studies and many other investigations.

J. Liq. Chromatogr. Relat. Technol. 33, 1005-1012 (2010). HPTLC of lipids (free sterols, free fatty acids, triacylglycerols, methyl esters, and steryl esters) on silica gel (plates with concentration zone) with petroleum ether - diethylether - glacial acetic acid 80:20:1. Detection by spraying with 5 % ethanolic phosphomolybdic acid reagent and heating for 10 min at 110 °C. Quantitative densitometric analysis was performed at 610 nm.

J. Chromatogr. Sci. 48(10), 825-829 (2010). TLC of ibuprofen and its impurities in pharmaceutical preparations on silica gel with toluene - ethyl acetate - glacial acetic acid 17:13:1. Quantification by densitometry. The limit of detection and quantification ranges from 0.13-0.27 µg/zone. The recovery is 96.8-99.0 % for the individual constituents. The method is suitable for routine quality-control analysis of pharmaceuticals containing ibuprofen.