J. Planar Chromatogr. 23, 79-83 (2010). HPTLC of anastrozole (2-[3-(1-cyano-1-methyl-ethyl)-5-(1H-1,2,4-triazole-1-yl-methyl)-phenyl]-2-methyl-propanenitrile) on silica gel (prewashed with methanol) with toluene - acetone - ammonia 60:40:3 in a twin-trough chamber previously saturated for 20 min. Quantitative determination by absorbance measurement at 200 nm. Recovery of anastrozole from 1mg tablet formulations ranged from 98.9 to 101.5 %. Intra-day and inter-day precision were 1.34 % and 1.59 %, respectively. LOD and LOQ were 71 and 214 ng/band. The correlation coefficient for the anastrozole calibration was 0.9983 over the range of 500-1500 ng/band (peak area).

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.

J. Food Comp. Anal. 23, 214-219 (2010) HPTLC of epicatechin (1), syringic acid (2), quercetin-3-O-galactoside (3), and quercitrin (4) in the leaves of Rhododendron species on RP18 with methanol - 5 % formic acid in water 1:1. Quantitative determination by absorbance measurement at 290 nm. The hRf values of (1), (2), (3), and (4) were 63, 47, 28 and 21, respectively. Linearity was between 200 and 1200 ng for (1), (3) and (4), and between 200 and 2400 ng for (2). The intra-day and inter-day precisions (expressed in terms of % RSD) for compounds (1) to (4) were in the range of 0.41-1.37 % and 0.67-2.04 %, respectively. LOD obtained for compounds (1) to (4) were 20, 40, 25 and 25 ng/zone, respectively while LOQ were 50, 115, 75 and 70 ng/zone, respectively. Recovery for all four compounds was in the range of 95.5-98.5 %.

Encyclopedia of Chromatography Third Edition 1, 2111-2115 (2009). The author describes the sample preparation methods prior qualitative and quantitative analysis by TLC and HPTLC. Classical extraction and clean-up methods include liquid-liquid extraction and soxhlet extraction. Modern methods such as solid phase extraction (SPE), pressurized liquid extraction (PLE), supercritical fluid extraction (SFE) and immunoaffinity (IA) extraction and clean-up are also described.

Indian J. Pharma. Sci. 70(4), 529-531 (2008). HPTLC on silica gel with ethyl acetate - acetone - acetic acid 13:6:1 with chamber saturation for 15 min. Densitometric evaluation at 208 nm. The hRf value was 51 for quinapril hydrochloride and 76 for hydrochlorothiazide. The method was linear in the concentration range of 400-2800 ng/zone for quinapril and 500-3500 ng/zone for hydrochlorothiazide. The recovery was in the range of 98.3-100.8 %.

Eurasian J. Anal Chem 4(2), 152-160 (2009). A stability indicating HPTLC method has been reported for estimation of aspirin and clopidogrel bisulphate in combined dosage form. HPTLC on silica gel with carbon tetrachloride - acetone 5:2. The hRf value of aspirin was 13 and of clopidogrel 78. Densitometric evaluation at 220 nm. Linearity was in the range of 200-600 ng/spot for aspirin and 300-600 ng/spot for clopidogrel. Degradation products (acid, base oxidative, dry heat, photodegradation) did not interfer with the analysis.

Eurasian J. Anal. Chem. 5(1), 25-27 (2010). An HPTLC method is reported for estimation of levodopa in seeds of Mucuna pruriens and its herbal formulation. HPTLC on silica gel with n-butanol - glacial acetic acid - water 5:1:4. Densitometric evaluation at 280 nm. The hRf value of levodopa was 39. The method was linear in the range of 100-1000 ng/band. The method is suitable for estimation of levodopa in herbal formulation.

Journal of Pharmacy Research 2(1), 189-195 (2009). A validated HPTLC method has been developed for simultaneous estimation of valdecoxib and tizanidine in dosage form. HPTLC on silica gel with toluene - methanol - ethyl acetate 2:2:1. The compounds were well separated as compact bands. The method was linear in the range of 10-100 ng/band for tizanidine and 100-1000 ng/band for valdecoxib. The recovery was in the range of 99.3-101.2 %. Densitometric quantification at 254 nm. The method is suitable for quality control of combined dosage form.