by thin-layer chromatography) (Chinese). J. Chinese Trad. Patent Med. (Zhongchengyao) 27 (8), 941-944 (2005). TLC of betaine on silica gel with acetone - ethanol - hydrochloric acid 10:6:1. Detection by spraying with a solution of potassium iodobismuthate. Quantitative determination by densitometry at 515 nm. Validation regarding linearity range (8.0 - 39.0 µg, r = 0.9992), precision (RSD = 1.62 %, n = 6), reproducibility (RSD = 2.14 %, n = 6), and recovery (99.75 %, RSD = 1.92 %, n = 6). Results are given for 12 real life samples. Discussion of the advantages of the method compared to HPLC.

Anal. Sci. 22, 743-745 (2006). HPTLC of gatifloxacin and ornidazole on silica gel with n-butanol – methanol 8:1 and 1 drop ammonia with chamber saturation for 45 min. Quantitative determination by absorbance measurement at 302 nm. Linearity of determination of gatifloxacin is 100 – 500 ng and of ornidazole 250 – 1250 ng, with a correlation coefficient of more than 0.9850. The intra-day and inter-day coefficients of variation are found to be in the range of 0.68 - 2.58 % and 0.37 - 3.62%, respectively.

J. Liq. Chromatogr. Relat. Technol. 29, 1891-1903 (2006). HPTLC of androsterone, epi-androsterone, dehydro-epi-androsterone, testosterone, stigmasterol, beta-sitosterol, estradiol, hydrocortisone, and cholesterol on RP-18 W with methanol - water, and acetonitrile - water in different composition, with chamber saturation. Detection by spraying with sulfuric acid - methanol 1:9 and heating at 120 °C for 15 min. Densitometric determination of RF values. The aim of the work was to compare the lipophilicity of selected steroids determined by RP-HPTLC on RP-18 W plates using different mobile phases with lipophilicity values estimated by computational methods.

J. Liq. Chromatogr. Relat. Technol. 29, 1503-1514 (2006). TLC of tanshinones (cryptotanshinone, tanshinone I, tanshinone II A) on silica gel with light petroleum (60-90°C) - ethyl acetate 4:1. Evaluation and scanning densitometry at 280 nm. With TLC 8 stable components were separated in common within 48 min, respectively, from 3 crude samples of Salvia miltiorrhiza Bunge from different growth locations. With High Speed Countercurrent Chromatography (HSCCC) 12 components were separated, respectively, with good correspondence and precision within 13 h. Both TLCS and HSCCC were effective in showing the whole concentration distribution of all kinds of constituents in different samples. HSCCC showed better performance in analysis of tanshinones, which produced a fingerprint which contained more chemical information than that of TLCS.

J. Sep. Sci. 30, 708-712 (2007). HPTLC of icariin in the aerial part of Epimedium koreanum Nakai on silica gel with ethyl acetate – glacial acetic acid – formic acid – water 10:1:1:2. Quantitative determination by absorbance measurement at 270 nm. The LOD and LOQ for icariin were 66 and 215 ng/band, respectively. Results did not show statistical significance between HPLC and HPTLC.

J. Planar Chromatogr. 20, 53-56 (2007). HPTLC of flavonoids (quercetin glucuronide, hyperoside, isoquercitrin, quercetin galloyl galactoside, quercitrin) on silica gel with ethyl acetate - formic acid - water 136:5:6 in a horizontal chamber. Densitometric quantitfication of flavonoids at 350 nm.

J. Planar Chromatogr. 20, 57-60 (2007). TLC of 5-methylcytosine, tryptamine, melatonin, tryptophan, indole-3-acetic acid, and indole on silica gel with 1-butanol - glacial acetic acid - water 12:3:5 and isopropanol - 25 % ammonia - water 8:1:1. Densitometry at 280 nm.

59th Indian Pharmaceutical congress C-299, 296, (2007). The gastroprotective drug Gastse was prepared by mixing standardized alcoholic extracts of Capsicum annum, Chelidonium majus, Strychnos nux vomica, and Arsenicum album. HPTLC of Gastse on silica gel with n-hexane - ethyl acatate 52:6. Evaluation at UV 254 nm and 366 nm. Densitometric determination at 200 nm and 400 nm.