J. Planar Chromatogr. 24, 474-481 (2011). TLC of the active S-(+)-enantiomer escitalopram oxalate (ESC-OX), escitalopram cyanodiol, the R-enantiomer and escitalopram N-oxide impurities on silica gel (containing beta-cyclodextrin as chiral additive) with acetonitrile - 0.1 % acetic acid - water 10:1:6:2 with chamber saturation for 30 min. Using 3 mg urea per 100 cm2 of silica-coated plates as a chiral additive also achieves a good enantiomeric separation with acetonitrile - 1 % acetic acid - ethyl acetate - methanol - water 10:1:2:4:3. Detection at 254 nm. Quantitative determination by absorbance measurement of ESC-OX at 240 nm. The hRf values of ESC-OX, escitalopram cyanodiol, the R-enantiomer and escitalopram N-oxide were 75, 40, 31, and 23, respectively. The linearity was 0.25-10 mg/10 mL (r = 0.9991). Accuracy was 99.7 %. LOD and LOQ were 13 and 44 µg/mL for ESC-OX.

Anal. Biochem. 172, 484-487 (1988). HPTLC on silica with butyl acetate - ethyl acetate 5:1, chloroform - butyl acetate - ethyl acetate 3:3:1, chloroform - butyl acetate - ethyl acetate -triethylamine 12:2:4:1. Preservation of the chromatograms by dipping in 10% paraffin oil in cyclohexane and heating. Quantification by fluorodensitometry at 366/>400 nm. Detection limit, 1-4 p mol.

Chromatographia 40, 96-98 (1995). Study of the behavior and separation ability of cellulose, starch and aminoplast thin-layers with aqueous and non-aqueous mobile phases by measuring the retention of a homologous series of benzamides. Discussion of the retention behavior and separation ability in terms of the nature of the solute, support and eluent.

Analytical Science 25(1), 57-62 (2009). HPTLC of minocycline on silica gel plates previously treated with 10 % EDTA solution of pH 9.0 with methanol - acetonitrile - isopropyl alcohol - water 10:8:1:1. The hRf value was 32. Densitometric evaluation at 345 nm. The method was linear in the range of 100-1200 ng/band for all biological samples. The average recovery was 95.1 %. The method was found suitable for estimation of the drug in different biological fluids (human plasma, saliva, gingival fluid) and can be used for pharmacokinetic studies.

J. Planar Chromatogr. 24, 222-226 (2011). HPTLC of lamotrigine in human serum with chloramphenicol as internal standard on silica gel, prewashed with methanol, with ethyl acetate - methanol - 32 % aqueous ammonia 17:2:1 in a saturated twin-trough chamber. Quantitative determination by densitometry at 280 nm. The hRf of lamotrigine was 37. Linearity was between 0.6 and 300 ng/band, corresponding to 0.06-30.00 ng/µL lamotrigine in human serum after extraction and application of 1 µL to the chromatographic plate. The correlation coefficient was 0.998. Intra-assay and inter-assay precision (%RSD) were in the range of 0.5-2.9 % (n = 3) and 1.6 -2.9 % (n = 9), respectively. LOD and LOQ were 16 and 42 pg/zone, respectively. Recovery (by standard addition) was between 94.1-101.3 %, with %RSD not higher than 3.5 %.

J. Chromatogr. 427, 121-130 (1988). TLC of cyclophosphamide and its metabolites on silica with chloroform - ethanol - acetic acid 100:20:1. Detection by spraying with 5% 4- (4-nitrobenzyl)pyridine in acetone-0. 2 M acetate buffer pH 4. 6 8:2 and heating at 130-150°C for 5-15 min. and dipping in 3% methanolic potassium hydroxide. Photography of the chromatogram within 10 seconds. Quantification by densitometry. Detection limit, 0. 5-1 µg/L. The calibration curves were found linear over a range of 1-250 µg/mL.

J. Planar Chromatogr. 7, 428-434 (1994). Investigation of a series of twelve model iminodiethanol congeners with 26 RP-TLC systems comprising three different silica layers with varied hydrocarbonaceous modification. Methanol - water or acetonitrile - water, in different proportions were used. Solute log k showed linear or quadratic dependence on the concentration of organic modifiers in the mobile phase. Detection with ninhydrin.

International Journal of ChemTech Research 2(1), 646-652 (2010). TLC on silica gel with toluene - methanol - triethylamine 9:3:1 with chamber saturation for 30 min. The hRf value was 71. Densitometric evaluation at 282 nm. The method was linear in the range of 100-2000 ng/band with r2 = 0.9973. The repeatability of sample application and measurement of peak area (%RSD, n=6) was 0.461 % and 0.363 %. The %RSD for intra-day and inter-day variation was 0.752-0.961 % and 0.848-1.082 % respectively. The LOD and LOQ was 10 and 50 ng/zone, respectively. The average recovery was 99.5 %. The samples were subjected to stress conditions (acid, base, oxidative, thermal) and all degradation products were well resolved from the main compound. The method was found suitable for stability studies and for routine analysis of the drug in biological fluids.