Apoth. Ztg. 139, 628-629 (1999). HPTLC of budesonide with prednisolone acetate, dexamethasone acetate or betamethasone 17a-valerate as reference substance on silica gel with ethyl methyl ketone - toluene 2:3 without chamber saturation, bandwise application. The plate is left for 15 min in the air after application. Detection under UV 254 nm, after spraying with 20% ethanolic sulfuric acid and heating at 110°C for 5 min. Visualization under day light and under UV 360 nm.

J. Chromatogr. A 1509, 147-152 (2017). Presentation of proper sigmoidal dose-response curves which can be linearized by the logit function resulting in logit-log plots in semi-log plots, from a planar yeast estrogen screen (pYES) as known for the evaluation of enzyme-linked immunosorbent assays and radioimmunoassays in microtiter plates. It was assumed to obtain sigmoidal shaped dose-response curves from the measured sign plots because pYES represents the transfer of the receptor assay YES to HPTLC. As no typical sigmoidal curves were obtained when peak areas were plotted against the applied amount on a logarithmic scale, peak heights were examined in the present study, which revealed proper dose-response curves when plotted against the log amount. The presence of sigmoidal dose-response curves from HPTLC-pYES made it possible to transform the signals into logits and, therefore, to create logit-log plots with linear correlations. The working range was up to 500 pg/zone for both 17β-estradiol (1) and 17α-ethinylestradiol (2). The mean recovery by applying logit-log plots for (1) and (2) from spiked water samples (2-20 ng/L) were 90 % and 108 %, respectively, with %RSD≤24 %. Determination of the half maximal effect dose (ED50) of the estrogen active compounds, which was represented by the intersection of the linear graph with the abscissa and also determination of the estrogenic potential in terms of estradiol equivalent factors by using the ED50 values, resulting in 0.64 for (2).

J. Planar Chromatogr. 8, 200-204 (1995). Study of the retention behavior of a series of steroids in liquid - solid chromatography as a function of the concentration of the diluent in ternary nonaqueous mobile phases. The relationship between the retention constant RM and the concentration of a diluent in the mobile phase was linear, with the slope values depending on the molecular structures of the compounds.

J. Planar Chromatogr. 27, 466-471 (2014). HPTLC of (1) flumethasone pivalate, (2) flumethasone, and (3) clioquinolon on silica gel with benzene – hexane – acetone – formic acid 500:400:200:13. Quantitative determination by absorbance measurement at 235 nm. The hRF values of (1) to (3) were 31, 7 and 64, respectively. Linearity was in the range of 30-400 ng/zone for (1), 50-300 ng/zone for (2) and 150-500 ng/zone (3). The intermediate precision was below 2 % (n=3) for (1) to (3). The LOD and LOQ were 9 and 27 ng/zone for (1), 13 and 39 ng/zone for (2) and 41 and 123 ng/zone for (3). Recoveries for (1) to (3) were in the range of 90-110 %. The method was statistically compared to a validated HPLC method.

– a botanical source of the Ayurvedic drug Jivanti. J. Planar Chromatogr. 31, 150-154 (2018). HPTLC of β-sitosterol (1), lupeol (2), and oleanolic acid (3) in Leptadenia pyrotechnica with toluene – ethyl acetate 9:4 for (1); toluene – ethyl acetate – formic acid 70:30:3 for (2), and toluene – methanol – formic acid 45:20:1 for (3). Detection by spraying with freshly prepared p-anisaldehyde sulfuric acid reagent, followed by heating at 110 °C for 3 min. Quantitative determination by absorbance measurement at 530 and 540 nm. The hRf values for (1) to (3) were 64, 84 and 47, respectively. Linearity was in the range of 2-10 μg/zone for (1) to (3). The intermediate precision was below 0.6 %. The LOD and LOQ were 410 and 1270 ng/zone for (1), 550 and 1680 ng/zone for (2) and 300 and 920 ng/zone for (3), respectively. Average recovery for (1) to (3) was 99 %.

Pharm. Anal. (Yaowu Fenxi Zazhi) 5, 113-114 (1985). (Chinese). (Detection of some steroids in dexamethasone sodium phosphate by TLC.) TLC on silica with dichloromethane - ether - methanol - water 27:15:8:1.2. Spot visualization under UV. Detection limit 410 ng.

Acta Pharmaceutica Jugoslavica 39, 137-141 (1989). TLC of sterol glucosides on cellulose with ethyl acetate - pyridine - acetic acid - butanol - water 25:20:20:50:10; identification of glucose. TLC of aglycones on silica impregnated with 10% silver nitrate with dichloromethane - chloroform 3:2; identification of ß-sitosterol, stigmasterol and campesterol acetate.

J. of Natural Products 55, 1648-1654 (1992). Isolation of 3 cytotoxic sterols from a lipophilic extract by PTLC on silica with isopropanol - hexane 1:9, followed by reverse-phase PTLC on RP-18 silica with methanol - water 9:1.