J. AOAC Int. 86, 909-915 (2003). In quality control and stability testing of herbal medicinal products, fingerprint chomatograms are used as powerful tools to evaluate and compare the composition of compounds in such products. To fulfill the ICH- and GMP-based regulatory requirements in pharmaceutical QC, chromatographic fingerprint analysis needs to be validated. By considering the stationary phase, sample application, developing solvents, chromatogram development, plate labeling, derivatization, documentation, and chromatographic equipment the paper provides a comprehensive concept for evaluating validation parameters for planar chromatographic fingerprinting based on a standardized methodology. Validation parameters addressed include stability of the analyte, selectivity, robustness testing, and method reproducibility.

J. Planar Chromatogr. 17, 36-39 (2004). TLC of saussurine on RP-18 after preconditioning for 15 min with e. g. methanol - water 2:1, tetrahydrofuran - chloroform 4:1, and methanol - water - glacial acetic acid 80:4:1; the last was found to enable the optimum separation. Detection by treatment with Dragendorff’s reagent. Quantitative determination at 540 nm. Limit of detection 3 µg.

Chinese J. Trad. Patent Med. (Zhongchengyao) 26 (4), 343-345 (2004). TLC of ephedrine chloride on silica gel with chloroform - methanol - ammonia 200:35:6. Detection by spraying with 0.5 % ninhydrin in ethanol followed by heating at 105 ºC for a few minutes. Quantitative determination at 510 nm. Validation of the method by investigation of linear range of the calibration curve (0.42 - 2.10 µg/spot, R = 0.999), precision (RSD = 2.1 %, n=6 within plate and 2.7 %, n = 5 plate-to-plate), reproducibility (RSD = 2.3 %, n = 5), and recovery (98.1 %, n = 6). The results obtained by using the method are given towards some real-life samples.

Chinese J. Trad. Patent Med. (Zhongchengyao) 26 (7), 597-600 (2004). TLC of Qieban Zhiyang ointment extracts on silica gel with 1) benzene - ethyl acetate 10:1; 2) petroleum ether (60-90 ºC) - ethyl formate - formic acid 15:5:1; 3) chloroform - methanol - ammonia 40:3:1; 4) benzene - chloroform - acetone 5:4:1; 5) chloroform - methanol 19:1. Detection 1) under UV 365 nm; 2) by exposing to ammonia vapor; 3) by spraying with potassium iodobismuthate solution; 4) under daylight. Identification by fingerprint technique. Quantification of icariine by HPLC.

J. Planar Chromatogr. 17, 454-458 (2004). HPTLC of lipids and phospholipids (tricylglycerols, free sterols, free fatty acids, steryl esters, phosphatidylcholine, phosphatidylethanolamine) on silica gel with petroleum ether - diethyl ether - glacial acetic acid 80:20:1 in a presaturated twin-trough chamber. Detection by spraying with 5 % phosphomolybdic acid in ethanol, followed by heating for 10 min at 115 °C. The neutral lipids are visible as blue spots on a yellow background. For polar lipid analysis, plates were developed with chloroform - methanol - water 65:25:4 and sprayed with 10 % cupric sulfate, followed by heating for 10 min at 140 °C, to detect phospholipids as brown spots on a white background. Quantitative determination by densitometric analysis at 610 nm for neutral lipids and at 370 nm for polar lipids.

56th IPC 2004, Abstract No. GP-46. Stability indicating HPTLC determination of cefuroxime axetil in bulk drug and in formulations on silica gel with chloroform - methanol 23:2. Quantitative determination by scanning at 278 nm. The sample was subjected to acidic, and alkali hydrolysis, oxidation and photo degradation. The degraded products were well separated. The method was validated for accuracy, precision, linearity, specificity, ruggedness, and recovery (98 - 100 %).

IPC 56th 2004, Abstract No. G-5. HPTLC of conessine in Holarrhena antidysentrica, an important ayurvedic drug, on silica gel with toluene - ethyl acetate - diethyl amine 13:5:2. Detection by spraying with Dragendroff’s reagent. Quantitative determination by densitometric scanning at 520 nm. Different market samples of the drug were found to contain 0.30 - 1.46 % of conessine with recovery of 95.18 - 102.70 %

J. Planar Chromatogr. 17, 238-240 (2004). HPTLC of aceclofenac and mosapride citrate (as internal standard) on silica gel in a twin-trough chamber equilibrated with the mobile phase with toluene - methanol - ethyl acetate - glacial acetic acid 550:250:200:1. Quantitative determination by densitometry at 284 nm.