J. Pharm. Biomed. Anal 36, 617-620 (2004) HPTLC of caffeine in herbal products and energy drinks, on silica gel with ethyl acetate - methanol 17:3. Solid samples (capsules) were extracted with methanol, filtered and applied whereas liquid samples (coca cola) were applied after the effervescence has ceased. Quantitative determination by absorbance measurement at 275 nm. The developed method was validated for specificity, repeatability (CV < 5 %), recovery (98.90) and accurary (99.84). The levels of caffeine were 4.76-13.29 % and 0.011-0.032 % for the herbal products and the energy drinks resp.

J. Planar Chromatogr. 19, 223-227 (2006). HPTLC of leuprolide acetate (a synthetic nonapeptide analog) on silica gel after prewashing with chloroform - methanol 1:1 using five-step isocratic incremental multiple development with ethyl acetate - methanol - 25 % ammonia. Detection under UV light at 254 and 280 nm. Quantitation by reflectance scanning at 280 nm.

Indian Drugs 42 (7), 424-427 (2005) HPTLC of fexofenadine HCl from tablet dosage form on silica gel with dichloromethane - methanol 13:7. Quantitative determination by absorbance measurement at 260 nm. The linear detector response was observed between 0.2 and 1.0 µg. The method was validated to determine its accuracy and precision. The LOD was found to be 0.08 ng/µL, LOQ was 0.02 ng/µL. The recovery was carried out by standard addition method and was found to be 100.82 %.

J. Sep. Sci. 27, 129-131 (2004). HPTLC of betulin in the bark of Grewia tiliaefolia Vahl. on silica gel with toluene – ethyl acetate 9:1. Quantitative determination by absorbance measurement. Linearity of determination of betulin is between 1000 and 1800 ng and its average percentage recovery is 96.09 - 98.87 %.

J. AOAC Int. 89, 1300-1304 (2006). TLC of 27 substandard drugs on silica gel with appropriate mobile phases. Routine Minilab (developed by the German Pharma Health Fund) test procedures to screen product quality and a proficiency testing program to determine the competency of health inspectors and reliability of results were established. Although the TLC screening methods provide a rapid means for drug quality assessment, they need to be put in the hands of competent users.

Indian Drugs 44 (2), 111-116 (2007). HPTLC for simultaneous determination of mosapride citrate and pantoprazole from pharmaceutical formulations by using loratadine as an internal standard. HPTLC on silica gel with toluene - acetone - methanol 16:4:1. Quantitative determination by absorbance measurement at 254 nm. Mosapride citrate response was linear over the range 0.075 - 0.225 µg/mL, and that for pantoprazole was 0.2 - 0.6 µg/mL. Recovery was 99.6 - 101.3 % for both compounds. The developed method was validated regarding accuracy, precision, and stability, and can be used for routine quality control of formulations containing mosapride citrate and pantoprazole.

Indian J. Pharm. Sci. 68 (6),788-789 (2007). HPTLC of etorocoxib in dosage forms on silica gel with chloroform - methanol - toulene 2:1:2. The plate was scanned at 289 nm for quantitative evaluation. The hRf value of etorocoxib was 58. The method was linear in the range of 100 - 600 ng/spot.The method was validated for accuracy, precision and repeatability. It was found suitable for routine quality control of formulations.

J. Planar Chromatogr. 20, 43-48 (2007). Two dimensional TLC of flavonoids (with quercetin 3-rhamnoside, quercetin 3-glucoside, quercetin 3-rutinoside, catechin, and gallic acid as markers) on cellulose with n-butanol - acetic acid - water 6:4:1 in the first direction and 15 % acetic acid in the second direction; TLC of phenolic acids on cellulose with toluene - methanol - acetic acid - acetonitrile 16:2:1:1 in the first direction and sodium formate - formic acid - water 10:1:200 in the second direction. Flavanols were separated on silica gel with chloroform - methanol - water 13:7:2 in the first direction and ethyl acetate - formic acid - acetic acid - water 75:3:2:20 in the second direction. Chromatograms were developed in a horizontal chamber after saturation for 10 min. Detection after drying by UV light at 254 and 366 nm. Detection also by spraying with 5 % aluminium chloride in methanol for flavonoids, with aqueous 5 % iron(III) chloride for gallic acid,1 % diazosulfanilamide in acetone and 1 % vanillin in hydrochloric acid for flavanols. After spraying with vanillin solution plates were heated at 110 °C for 5 min and viewed in white light and, after 30 min, under UV light at 366 nm. Also TLC of flavonoids (astragalin, quercetin 3-galloylglucoside, rutin, hyperoside, quercitrin, kaempferol 3-rhamnoside on silica gel with ethyl acetate - methanol - formic acid - acetic acid - water 80:10:1:1:8. For an identity test natural product reagent, 0.5% diphenylborinic acid 2-aminoethylester in ethyl acetate, was used. After develoment the plates were heated at 100 °C for 3 min and immediately immersed in the NP reagent, then viewed under UV light at 366 nm and in white light.