Abstract No. C-258, 61st IPC (2009). HPTLC of piperine, plumbagine and zingiberine in Panchkol Churna, an ayurvedic preparation used for anorexia, distension and abdominal pain. HPTLC on silica gel with toluene - ethyl acetate 7:3. Densitometric evaluation at 340 nm for piperine, and at 420 nm for plumbagine and zingiberine. The hRf value of piperine, zingiberine and plumbagine was 31, 75, and 84.

Abstract No. C-291, 61st IPC (2009). Quantitative determination of curcumin in the marketed herbal product Rheumax (Herbajules rumatis) containing extracts of Curcuma longa, Boswellia serrata, Tinospora cordifolia and Vitex negundo by TLC on silica gel with chloroform - methanol 37:3. The hRf value of curcumin was 59. Quantitative absorbance measurement at 430 nm. The linear regression between 100 and 500 ng/zone showed R2 of 0.99984 and RSD of 1.58 % for curcumin.

Analytical Sciences 26 (4), 467-472 (2010). TLC of terbutaline sulphate on silica with chloroform - methanol 9:1. The hRf value was 34. Densitometric evaluation at 366 nm. The method was linear in the range of 100-1000 ng/band. The recovery was being 99.6 %. When subjected to different stress conditions (acid, base, oxidative, and UV) the drug was not stable under acidic condition but stable under all other conditions. All degradation products are well resolved from the main compound. The proposed method is stability-indicating and suitable for quality control.

J. Sci. Res. 1(1), 121-127 (2009). An HPTLC method is described for qualitative and quantitative estimation of sinapic acid in Lepidium sativum (Brassicaceae). Methanolic extracts of the plant material were subjected to chromatographic separation on HPTLC silica gel with n-butanol - acetic acid - water 4:1:5. Derivatization with anisaldehyde sulfuric acid reagent, followed by heating at 110 °C for 10 min. Denstiometric quantification at 326 nm. Identification was confirmed by comparison of hRf-values of sample and standard.

International Journal of PharmTech Research 1(4), 1644-1649 (2009). TLC of telmisartan and amlodipine besylate on silica gel with tetrahydrofuran - dichloromethane - methanol - 25 % ammonia 30:10:5:1. The hRf value for telmisartan was 22 and for amlodipine 45. Densitometric evaluation in absorbance mode at 326 nm. The method was linear in the range of 1200-7200 ng/band for telmisartan and 400-1400 ng/band for amlodipine. The average recovery was 100.7-101.5 %.

Asian Journal of Chemistry 22(8), 5951-5955 (2010). TLC on silica gel with cyclohexane - methanol - ethyl acetate - 25 % ammonia 10:3:6:1. The hRf value was 7 for atenolol and 69 for nifedipine. Densitometric evaluation at 230 nm. The linearity was in the range of 3-21 µg/band for atenolol and 1.2-8.4 µg/band for nefidipine. The recovery was 100.7 % for both drugs. The method was found suitable for analysis of the combined dosage form of atenolol and nefidipine without interference of excipients.

J. Planar Chromatogr. 23, 265-269 (2010). TLC of the epimers of cefaclor on silica gel (impregnated with beta-cyclodextrin by development with 1:9 aqueous beta-cyclodextrin solution - methanol) with chloroform - ethyl acetate - glacial acetic acid - water 4:4:4:1 with chamber saturation. Chromatograms were developed at 5 °C and dried at room temperature. Quantitative determination by absorbance measurement at 274 nm. The limit of detection was 0.24 and 0.27 µg/band for the epimers at hRf 26 and 33, respectively. The limit of quantification was 0.74 and 0.83 µg/band, respectively. The recovery was between 100.0 and 100.8 % and the precision between 0.7 and 1.7 %.

J. Planar Chromatogr. 23, 286-288 (2010). TLC of taxol with a stationary-phase gradient whereby parts of different TLC plates were connected by use of a MIGAS device. Separated taxol-containing zones were developed with methanol over 1 cm and thus moved to another plate. The lipophilic substance zone was cut out after separation of the sample on a silica gel plate with n-heptane - ethyl acetate 1:1. Further separation of taxol from accompanying hydrophilic substances was carried out on HPTLC RP-18W with methanol - water 4:1. The taxol-containing fraction was finally separated on silica gel with chloroform - acetone 3:1 in a horizontal chamber at constant temperature (30 +/- 1°C) and humidity (35 +/- 1 %). Detection under UV 254 and 366 nm. Quantitative determination by densitometry at 220 nm. The precision (n = 7) was 0.63 % and the repeatability (n = 7) 3.35 %. The limit of detection and quantification was 0.50 and 1.00 µg/zone, respectively; the correlation coefficient from linear regression was >0.98, and the linear calibration range was 1 - 10 µg/zone.