J. Planar Chromatogr. 17, 375-378 (2004). HPTLC of parthenolide and extracts of feverfew capsules on silica gel with ethyl acetate - n-hexane 3:2 in glass chambers presaturated for 30 min. Detection by dipping in p-anisaldehyde reagent and heating at 105 °C for 5 min, followed by immediate densitometric scanning at 543 nm. The method is precise with CV < 5%; calibration recovery of 101.12 +/- 4.11 % and overall accuracy of 101.14 +/- 4.47 %. The levels of parthenolide in the products analyzed ranged from 0.03 to 0.24 %.

J. Planar Chromatogr. 17, 383-387 (2004). TLC of fenbufen, ibuprofen, ketoprofen, diclofenac sodium, mefenamic acid, and tiaprofenic acid on silica gel by ascending and horizontal techniques, and on RP-18 in horizontal chambers. Good separation was achieved on silica gel by horizontal development with chloroform - methanol - 25 % ammonia 67:25:8; reversed phase chromatography on RP-18 with 0.15 mol/L phosphate buffer, pH 5.73 - 10 % CTMA-Br (N-cetyl-N,N,N-trimethylammonium bromide) in methanol 7:13 enabled better separation of the six drugs. Detection under UV light at 254 nm - for ibuprofen detection was best achieved after normal phase chromatography with 20 % aqueous sodium carbonate solution. A simple videodensitometric procedure was developed and validated. RSD for quantitation of fenbufen was 2.44 - 3.10 %.

IPC 56th 2004, Abstract No. GP-26. HPTLC of triphala, an ayurvedic formulation containing about 3.60 % of total phenolics. Separation of alcoholic triphala extracts on silica gel with n-hexane - ethyl acetate 2:1. Rf value of the main spot gallic acid was 0.04 in triphala and its formulation. The method was found to be very specific for gallic acid having a linearity range of 0.2 - 1.6 mg/mL. Several formulations analyzed by HPTLC contained 5.2 - 7.6 % of gallic acid. The reported method is suitable for estimation of gallic acid in raw material and formulations.

Part II. J. Chromatogr. A 1007 (1-2), 157-164 (2003). Quantitative structure–activity relationship (QSAR) analysis of H1-antihistamine activity was carried out and chromatographic data of 2-[2-(phenylamino)thiazol-4-yl]ethanamine, 2-(2-benzyl-4-thiazolyl)ethanamine, 2-(2-benzhydrylthiazol-4-yl)ethylamine derivative, and 2-(1-piperazinyl- and 2-(hexahydro-1H-1,4-diazepin-1-yl)benzothiazole derivatives were obtained. Silica gel impregnated with solutions of selected amino acid mixtures (-Asp, Asn, -Thr and -Lys) were used in two developing solvents as human histamine H1-receptor (hH1R) antagonistic interaction models. Lipophilicity data of the examined compounds were obtained and used in the QSAR assay. Using regression analysis, relationships between chromatographic and biological activity data were found. The correlations obtained in the present experiment with NP-TLC are more significant that those obtained in the experiment with RP2-TLC because of the optimal fitting of the chromatographic system conditions to the lipophilicity of solutes. All proposed chromatographic models should facilitate pre-selection of the new drug candidates. The correlations of calculated pA2(H1) values of the tested compounds predicted by the use of the best equations versus their pA2(H1) obtained from the biological tests were significant (R2= 0.91-0.94).

J. Planar Chromatogr. 18, 147-150 (2005). HPTLC of acteoside from leaves of Plantago lanceolata on silica gel with ethyl acetate - formic acid - water 18:1:1. Quantitative determination by densitometry at 334 nm. Intra-day and inter-day RSD were 0.58 and 2.0 %, respectively. Instrumental precision and repeatability of the method (CV) were found to be 0.62 and 1.5 %, respectively. The average recovery was 102.3 %.

Juss) and commercial neem based formulations using HPTLC and extended length packed-columns SFC method. Chromatographia 62 (3-4), 183-195 (2005). Two chromatographic techniques are described for the separation and quantitative determination of azadirachtin A and B, salannin, and nimbin present in the crude extract of neem seed kernels and commercial neem based formulations. HPTLC separation of markers on silica gel with ethyl acetate - benzene 7:3. Visualization under UV 254 nm. The other technique was based on extended length packed column supercritical fluid chromatographic (PC-SFC) separation of the markers. Validation of both methods in terms of precision, robustness, recovery, limits of detection and quantitation. The analysis of variance (ANOVA) and Student’s t-test were applied to correlate the results of quantitative determination of markers by means of HPTLC and PC-SFC method.

Abstract CP-53, IPC (2005). HPTLC of andrographolide and wedelolactones in several market samples on silica gel with toluene - acetone - formic acid 9:6:1. Quantitative determination by absorbance measurement at 254 nm. The hRf value of andrographolide was 52 and of wedelolactone 58. Linearity was obtained between 200-400 ng/spot and 120-200 ng/spot respectively with recovery rates of 98.1-106.7 %. A complex coumarin from Eclipta alba was used as marker.

J. Planar Chromatogr.18, 217-220 (2005). TLC of rose-hip extracts and (+)-catechin and (-)-epicatechin as standards on cellulose and silica gel in a horizontal chamber, saturated for 15 min, with the upper phase of ethyl acetate - water - formic acid - acetic acid 125:20:3:2. Visualization under UV light at 254 and 365 nm before and after spraying with bis-diazotized sulfanilamide. Quantitative determination by absorbance measurement at 254 nm.