J. Planar Chromatogr. 16, 359-362 (2003). TLC of norethisterone and impurities (e.g. 17-epi-norethisterone, D4-nordione, 6-ketonor-ethisterone) on silica gel with chloroform - acetone 9:1 and chloroform -methanol 19:1. Visualization by derivatization with 10% ethanolic sulfuric acid and heating at 120°C for 2 min. Visualization under UV 366 nm. OPLC on silica gel with hexane and butyl acetate - chloroform 17:3. Evaluation by videodensitometry. Comparison of selectivity and efficiency of TLC, OPLC, and HPLC.

J. Planar Chromatogr. 16, 425-432 (2003). HPTLC of 9 new s-triazines (e.g. 2,4-bis(cyclopropylamino)-6-chloro-s-triazine, 2,4-bis(cyclobutylamino)-6-chloro-s-triazine etc.) on RP-18, cyano- and amino-modified silica gel with water - tetrahydrofuran, water - dioxane, and water - acetonitrile mixtures. Detection under UV 254 nm.

CBS 93, 5-7 (2004). HPTLC of N,N-diethylethane-1,2-diamine in metoclopramide finished products on silica gel with 32 % ammonia - methanol - dichloromethane 3:15:80 over 40 mm with chamber saturation. Detection by dipping in 0.2 % ethanolic ninhydrin solution for 1 s, followed by drying at 120 °C for 5 min. Quantitative determination by absorbance measurement at 480 nm and evaluation of peak area with polynomial regression. The correlation coefficient of the calibration curve is 0.9995, the residual standard deviation 2.19 %. Intermediate precision is 1.65 %. Recovery for 0.2-1.0 % impurity is 100.5 %. Limit of quantitation is 0.05 % impurity.

Indian Drugs 41 (6), 354-357 (2004). HPTLC on silica gel with toluene - methanol - acetone - 10 % ammonia 80:40:20:1. Quantitative determination by absorbance measurement at 254 nm. The Rf value of pioglitazone hydrochloride was found to lie between 0.49-0.55. The linear dynamic response was found to be 2.0-4.0 µg/spot for pioglitazone hydrochloride. The results of the analysis have been validated statistically and by recovery studies. A simple, fast, specific and precise HPTLC method has been developed for the estimation of pioglitazone hydrochloride in its tablet dosage form.

IPC 56th 2004, Abstract No. D-9. HPTLC for the standardization of the alkaloid conessine in several market formulations containing kurchi bark, on silica gel with toluene - methanol - chloroform 1:2:1. Detection by spraying with Dragendorff’s reagent. Densitometric evaluation at 460 nm. The method was validated for accuracy, precision, linearity range, specificity, LOD, LOQ and found suitable for routine analysis of herbal formulations containing Kurchi as main ingredient.

Part I. J. Planar Chromatogr. 17, 275-279 (2004). HPTLC of nicotinic acid and selected derivatives (methyl nicotinate, ethyl nicotinate, isopropyl nicotinate, butyl nicotinate, hexyl nicotinate, benzyl nicotinate, nicotinamide, N-methyl nicotinamide) on RP-18 with methanol - water in different volume proportions after chamber saturation for 30 min. Detection under UV light at 254 nm. Investigation of the lipophilicity by TLC and use of the data for quantitative structure-activity relationships.

J. AOAC Int. 87, 827-833 (2004). TLC of trimetazidine dihydrochloride and degradation products (e. g. piperazine and 2,3,4-trimethoxymethyl benzene) on silica gel with methanol - ammonia 200:3. Detection under UV light at 254 nm and densitometry at 215 nm. The method was applicable over a concentration range of 2.00-9.00 µg/spot with a mean percentage accuracy of 99.86 +/- 0.92.

J. Planar Chromatogr. 18, 450-454 (2005). TLC of twenty-seven 2-benzylsulfanybenzothiazole derivatives on silanized silica gel in a pre-equilibrated normal chamber with 0.05 M phosphate buffer (pH 7.4 or 3.0) and methanol as organic modifier. Detection under UV light at 254 nm.