J. Chromatogr. A 1571, 223-230 (2018). Evaluation of lipophilicity of 11 representative drugs, including six proton pump inhibitors (omeprazole, pantoprazole, rabeprazole, lansoprazole, ilaprazole, and tenatoprazole), an anti-vertigo drug, betahistine, nonsteroidal anti-inflammatory drug, ibuprofen, anti-malarial drug, atovaquone, an anti-HIV agent, atazanavir and a hormonal drug, calcitriol, by employing NP and RP separation modes. Investigation of the effect of different organic modifiers for the estimation of lipophilicity. Estimation of the quantitative descriptor of lipophilicity, the partition coefficient (logP) by suitably optimizing the solvent systems for normal and reversed phase TLC. The best mobile phase pairs were toluene – acetonitrile and water – methanol, respectively. Analysis of the dominant pattern in the data by using principal component analysis, hierarchical cluster analysis, as well as non-parametric methods like sum of ranking differences and generalized pair wise correlation. The results obtained from both separation modes were comparable and in good agreement with the computational data for all the drugs.

Kontakte (Darmstadt) 36-39 (1990). Explanation of physical aspects of TLC with reasonable approximations. Discussion of differences between observed and true retention values. Proposal of a general approach for the estimation of correction coefficients (including some real examples). Explanation of physical aspects of TLC with reasonable approximations.

J. Planar Chrom. 4, 402-405 (1991). Study of the dependence of the eluent front migration velocity in TLC on the pore volume and particle size distribution of the sorbent. Proposition and experimental confirmation of an equation which relates the velocity to the parameters of the chromatographic system.

J. Chromatogr. 673, 113-124 (1994). TLC determination of lipophilicity parameters on the basis of thermodynamically true RM values. Discussion of the superiority of methanol as compared with other modifiers and its physico-chemical behavior. Influence of the solvent pH on the silanophilic effect. Extrapolation to modifier-free condition (RMW value) to diminish the contribution of polar interactions. Comparison of the advantages and disadvantages of non-linear extrapolation procedures with linear regression.

J. Planar Chromatogr. 10, 18-25 (1997). Study of the distribution of different ion-pairing reagents, e.g. tetramethylammonium (TMA), tetrabutylammonium (TBA), cetyltrimethylammonium (CTMA), and trioctylmethylammonium (TOMA) by measurement of the absolute concentrations of the compounds in the stationary phase after chromatography (OPLC) on silica impregnated by immersion into a methanolic solution (0.05 M) of the reagents with methanol - water mixtures in different ratios. The behavior of acidic, neutral, and basic compounds were studied simultaneously. The chromatographic results showed good correlation with the concentration of the reagents measured on the layer.

J. Planar Chromatogr. 13, 254-256 (2000). Study of the physicochemical fundamentals of planar analytical test methods with analytical reagents forming poorly soluble products on reaction with the target compound. In the test methods the analytical reagent was applied to a porous planar system (paper, or an adsorbent layer spread on a support). It was shown that regularities in the planar test methods are similar to those observed in planar chromatography.

J. Liq. Chrom. Rel. Technol. 27, 1993-2002 (2004). Commercially precoated TLC and HPTLC silica gel plates, with enhanced brightness UV indicator were compared with comparable plates formulated with standard indicators. Results showed that the increased UV indicator plates had visually brighter backgrounds, however, the limits of detection did not improve. HPTLC and TLC on silica gel of caffeine and acetaminophen with ethyl acetate - glacial acetic acid 19:1, and salicylamide with methylene chloride - acetone 4:1 in a twin-trough chamber containing a saturation pad. Quantitative determination at 254 nm.

J. Planar Chromatogr. 28, 234-240 (2015). HPTLC of (1) omeprazole, (2) pantoprazole, (3) rabeprazole and (4) diclofenac from tablets on silica gel previously washed with methanol and activated at 105 °C for 20 min, with toluene - n-butanol - 25 % ammonia 30:70:2. Quantitative determination by absorbance measurement at 290 nm. The hRF values were 67 for (1), 38 for (2), 57 for (3) and 27 for (4). Linearity was between 50 and 500 ng/zone for (1), (2) and (3), and between 150 and 1500 ng/zone for (4). The interday and intraday precisions were below 2 %. The LOD and LOD respectively for (1) were 7 ng/zone and 24 ng/zone, for (2) 9 ng/zone and 30 ng/zone, for (3) 13 ng/zone and 43 ng/zone, and for (4) 25 ng/zone and 82 ng/zone. Recovery was 99.6 % for (1), 100.1 % for (2), 100.4 % for (3) and 100.1 % for (4).