59th Indian Pharmaceutical congress F-23, 395, (2007). HPTLC of aspirin and cilostazol in synthetic mixture on silica gel with methanol - ethyl acetate - toluene - ether 2:4:4:1. Linearity was between 75 and 600 ng/mL for aspirin and 100 and 800 ng/mL for cilostazol. Recovery was between 98 and 101 %.

CBS 97, 12-15 (2006). HPTLC of flavonoids from green tea (Camellia sinensis) on silica gel in a saturated twin-trough chamber with ethyl formate - toluene - formic acid - water 60:3:8:6. Detection by dipping the hot plate (heated at 100 °C for 2 min) into natural products reagent, followed by drying, dipping into polyethylene glycol 400 (10 g in 200 mL dichloromethane), and drying. Evaluation under UV 366 nm. With this method the geographical origin of the material can be determined. Toluene - acetone - formic acid 9:9:2 allows the discrimination of green from black and other speciality teas, based on the polyphenol pattern. Detection by dipping the hot plate into a solution of Fast Blue Salt B. Evaluation under white light. For investigation of the alkaloid profile ethyl acetate - methanol - water 20:2.7:2 and evaluation under UV 254 nm is used. The amino acid profile is analyzed by using 1-butanol - acetone - acetic acid - water 7:7:2:4. Detection by dipping in ninhydrin reagent, followed by heating at 110 °C for 3 min. Evaluation under white light.

Chromatographia 67 (3-4), 269-274 (2008). Presentation of a quantitative method using silica gel HPTLC plates, automated bandwise sample application, and automated visible mode densitomety for the determination of 24beta-ethylcholesta-5,22E,25-triene-3beta-ol (ECTO) in the aerial part of Clerodendrum phlomidis, which was used as a chemical marker for the standardization of C. phlomidis plant extracts. HPTLC on silica gel with chloroform - methanol 197:3. Detection by derivatization with anisaldehyde reagent. Quantitative determination by absorbance measurement at 650 nm. Linearity was between 150 and 400 ng/band with good correlation (r2 = 0.996).

CBS 100, 2-5 (2008). HPTLC of photodegraded UV filters and sunscreen on silica gel LiChrospher prewashed with methanol. AMD 2 development of UV filter standards photodegradation products with diisopropylether - n-hexane in 6 steps over 50 mm without preconditioning, and of sunscreen samples photodegradation products with t-butylmethylether - n-hexane in 7 steps over 50 mm with preconditioning, followed by drying at 120 °C for 30 min. Detection at 254 and 366 nm, followed by biodetection via dipping the plate in a Vibrio fischeri solution for 1 s and evaluation with the Bioluminizer (exposure time 55 s). Densitometric evaluation by multi-wavelength scan at 200-400 nm.

J. Chromatogr. Sci. 46 (4), 298-303 (2008). HPTLC of three surfactants, cetyltrimethylammonium bromide (CTAB), dodecyltrimethylammonium bromide (DTAB), and polyoxyethylene (20) sorbitan monolaurate (Tween 20), on silica gel with 5 % aqueous thiourea - acetone - methanol 3:1:1. Evaluation of the effect of the carbon chain length of alcohols (methanol, ethanol, n-propanol, and n-butanol) on the mobility of these surfactants. The comparative study was performed with sulfur- (thiourea) and oxygen- (urea) containing compounds in the eluent. Investigation of the interference on the resolution of the mixture of CTAB, DTAB, and Tween 20, due to presence of metal cations as impurities.

Asian J. Chem. 20(4), 2531-2538 (2008). TLC of melatonin on silica gel with toluene - ethyl acetate - formic acid 10:9:1. Quantitative determination by absorbance measurement at 290 nm. The method was linear in the concentration range of 100 to 600 ng/spot. The recovery of the drug from tablets (by standard addition method) was 99.7 %. Statistical analysis proves that the method is repeatable, selective and accurate for the estimation of the drug. Forced degradation studies showed the effect of variations in pH, UV light and high temperature on the stability of melatonin. As the proposed method could effectively separate the drug from its degradation products, it can be employed as a stability indicating method.

J. AOAC Int. 91, 1162-1167 (2008). HPTLC of curcumin, demethoxycurcumin, and bisdemethoxycurcumin as standards on silica gel prewashed with methanol using chloroform - methanol 97:3 in a twin-trough chamber at 23 °C and 31 % relative humidity. Quantitative determination by absorbance measurement at 430 nm.

Pharma Review 7(3), 168 - 170 (2008). HPTLC of amlodipine besilate and bisoprolol fumarate on silica gel with methanol - ethyl acetate - ammonia 50:60:5. Quantitative determination by absorbance measurement at 229 nm. The hRf values were 39 and 52 for amlodipine and bisoprolol respectively. The linear rangewas 500-1000 ng/spot for both components. The method was suitable for routine quality control of combine dosage form.