Indian Drug 44 (2), 122-127 (2007). HPTLC of ayurvedic medicated oil on silica gel in a twin-trough chamber with ethyl acetate - toulene 1:9 for fingerprint analysis, and ethyl acetate - methanol - water 200:27:20 for quantitative determination of colchicine.

J. Liq. Chromatogr. & Relat. Technol. 29, 2257-2270 (2006). HPTLC of 20 methyl-thiazole-oxadiazoline derivatives on RP 18 with mixtures of methanol - water with varying contents from 45 - 70 % in 5 % steps. Examination after drying under UV light at 254 nm.

J. Planar Chromatogr. 20, 335-339 (2007). TLC of etoricoxib (rofecoxib as internal standard) on silica gel in a filter-paper-lined twin-trough chamber previously saturated with mobile phase vapor for 30 min with toluene - 1,4-dioxane - methanol 17:2:1. Densitometric analysis of etoricoxib was performed in absorbance mode at 235 nm. The limits of detection and quantitation were 30 and 100 ng/zone, respectively.

J. Planar Chromatogr. 20, 149-152 (2007). HPTLC of nebivolol hydrochloride on silica gel prewashed with methanol with toluene - ethyl acetate - methanol - formic acid 8:6:4:1 in a saturated twin-trough chamber. Densitometric quantification at 285 and 298 nm.

J. Planar Chromatogr. 21, 107-112 (2008). Optimization and comparison of the acidic visualization methods most often used for steroids. OPLC of ethinyl estradiol, ’dienolether’ (3-methoxyestra-2,5(10)-dien-17b-ol), norethisterone, norethisterone acetate, norethisterone enanthate, nandrolone, and nandrolone decanoate on HPTLC silica gel with cyclohexanone - ethyl acetate - chloroform 1:1:1. Detection with sulfuric acid at three different concentrations, phosphomolybdic acid, and phosphoric acid with different heating temperatures for different times. Evaluation under UV 366 nm (sulfuric acid, phosphoric acid) and in white light (phosphomolybdic acid). It was found that derivatization at higher temperatures for shorter periods usually results in greater sensitivity, although heating for longer periods at lower temperatures leads to a more stable and robust result. Evaluation by videodensitometry.

Asian J. Chem. 19(5), 3375-3381 (2007). The TLC method described in USP 28 does not separate all the related substances of alprazolam. An alternative HPTLC method is described for separation and estimation of starting material and synthesis related intermediates in alprazolam: 2-chloro acetamide-5-chloro benzophenone (impurity 1) i.e. starting material, nordiazepam (impurity 2), thionordiazepam (impurity 3), 2-(2-aceto hydrazinyl)-7-chloro-5-phenyl-3H-1, 4-benzodiazapine (impurity 4). The hRf values of alprazolam, impurity 4, impurity 3, impurity 2, and impurity 1 were 25, 16, 77, 45, and 83 respectively. The HPTLC method developed is capable of detecting impurities at a level of 0.05%.

Asian J. Chem. 19(7), 5634-5638 (2007). TLC of rabeprazole sodium and itopride hydrochloride on silica gel prewashed with methanol, with toluene - chloroform - methanol - 25 % ammonia 5:6:2. Quantitative determination by absorbance measurement at 225 nm. Linearity was between 120 and 280 µg/mL for rabeprazole sodium and 900 and 1900 µg/mL for itopride hydrochloride. The recovery (by standard addition method) was between 98.1 and 99.5 % for both drugs. The proposed method is precise and accurate and can be used for routine analysis of rabeprazole sodium and itopride hydrochloride in capsule formulation.

Ind. J. Pharm. Sci. 70(3), 386-390 (2008). HPTLC for the simultaneous estimation of ondansetron combinations in solid dosage form with omeprazole and rabeprazole, on silica gel with dichloromethane - methanol 9:1. Quantitative determination by absorbance measurement at 309 nm for combinations of ondansetron with omeprazole and at 294 nm for ondansetron with rabeprazole. The hRf value of ondansetron and omeprazole was 42 and 54, respectively, while for ondansetron and rabeprazole hRF values were 41 and 51 respectively. Linearity was between 100 and 500 ng/spot for three drugs. The method can be employed for routine quality control of such formulation.