Indian J. Pharm. Sci. 67 (2), 182-186 (2005). HPTLC of atorvastatin calcium in its commercial single component tablet formulations (10 mg/tablet), on silica gel with benzene-methanol 7:3. The Rf value was 0.46. Quantitative determination by absorbance measurement at 281 nm. The method was validated in terms of linearity (200-600 ng/spot), precision (intraday variation: 0.25 - 1.01 %, interday variation: 0.21 - 0.88 %), accuracy and specificity. The LOD for atorvastatin calcium was 40 ng/spot, the LOQ was 200 ng/spot. The proposed method was successfully applied to determine atorvastatin calcium content of 10 individual tablet units of two market formulations after extracting atorvastatin calcium with methanol. All formulations were compliant with USP specifications (RSD less than or equal to 6 %) of the content uniformity test. The proposed HPTLC method can analyse ten or more formulation units simultaneously on a single plate and provides a faster and cost effective quality control tool for routine analysis of atorvastatin calcium formulation.

Mini review and chromatographic-computional analysis. Acta Chrom. 17, 9-19 (2006). Comparative correlative TLC analysis conducted on whole-tissue homogenate of control and in-vitro-incubated samples of mammalian myocardia and bullfrog cardiac muscle and thigh skeletal muscle. The focus in the study was on TLC-densitometric analysis of the endogenous cardiolipin of control samples and their respective incubated samples to identify the products, e. g. lysocardiolipin, formed during in-vitro incubation. TLC of the chloroform-methanol extracts (2:1) obtained after the incubation from the freeze-dried tissues homogenate on silica gel with 1-propanol - chloroform - ethyl acetate - methanol - water 50:50:50:21:18. Visualization with thionine reagent, densitometry at 600 nm.

C. Cheng by thin-layer chromatography) (Chinese). Chinese J. Pharm. Anal. (Yaowu Fenxi Zazhi) 25 (6), 719- 721 (2005). TLC of fulvotomentoside A on silica gel with chloroform - methanol - water 61:32:5. Detection by spraying with 10 % H2SO4 in ethanol followed by heating at 105 ºC for 5 min. Quantitative determination by densitometry at 518 nm. The procedure was validated regarding linearity range (1.20 - 7.20 µg/spot, r = 0.998), repeatability (0.51 %, n = 5), precision (0.21 %, n = 5 within plate and 0.87 % n= 5 plate-to-plate), and recovery (99.7 %, RSD = 2.45 %, n = 5). The results are given for three batches of real life samples.

Acta Chrom. 16, 153-163 (2006). HPTLC of salicylamide in diuretic tablets and pain-relief tablets on silica gel with concentrating zones (pre-washed with dichloromethane - acetone 1:1) with dichloromethane – acetone 4:1. Quantification by densitometry at 254 nm. The method is suitable for routine quality-control analysis of pharmaceuticals containing salicylamide.

J. AOAC Int. 90, 358-363 (2007). TLC of diosgenin on silica gel with n-hexane - ethyl acetate 4:1 with chamber saturation for 15 min. Detection by dipping into a modified anisaldehyde-sulfuric acid reagent (0.1 % anisaldehyde in 2 % sulfuric acid) in order to reduce charring and background interference, followed by drying for 10 min under hot air and heating at 105 °C for 10 min. Quantitative determination by absorbance measurement at 428 nm.

J. AOAC Int. 90, 113-127 (2007). TLC of bisacodyl [4,4’-(2-pyridylmethylene)-bisphenol diacetate], monoacetyl bisacodyl and desacetyl bisacodyl on silica gel with chloroform - acetone 9:1. Quantitative absorbance measurement at 223 nm. Concentration range for bisacodyl was 0.2 - 1.4 µg/band, mean recovery was 100.4 +/- 1.9 %.

J. Liq. Chromatogr. & Relat. Technol. 30, 1385-1400 (2007). TLC of alpha-tocopherol acetate, alpha-tocopherol, cholecalciferol, estradiol, testosterone, and hydrocortisone on silica gel, silica gel and kieselguhr, and aluminium oxide after prewashing with methanol; TLC of lipophilic vitamins on silica gel with toluene, and on RP-18 with methanol both with chamber saturation. Densitometric measurement at UV 254 nm. The resulting densitograms of the compounds studied indicate that applied sorbents have an influence on the wavelength of the obtained fundamental absorption band and the additional absorption bands, as well as on their intensity values.

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.