Analytical Chemistry - An Indian Journal 9(1) (2009). An HPTLC method has been developed for simultaneous estimation of paracetamol and ibuprofen. HPTLC on silica gel with ethyl acetate - acetone - n-butanol - 25 % ammonia 3:4:3:1. Densitometric quantification at 254 nm. The hRf value of ibuprofen was 32 and of paracetamol 86. The method was linear in the range of 120-600 ng/band for paracetamol and 130-650 ng/band for ibuprofen.

Asian Journal of Chemistry 23(1), 385-387 (2011). HPTLC on silica gel with chloroform - ethyl acetate containing 1 % acetic acid. Two well resolved zones with hRf values of 33 and 55 were obtained by illumination at 254 nm. The zones were labelled as substance I and II and used for standardization of the oil. Densitometric evaluation at 265 nm. The linearity range for both substances was 4-100 µg/band. The recovery was in the range of 97.4-98.7 %. Several commercially available tablets and capsules were analyzed for the content of Neem oil using substances I and II as marker (in the absence of chemical markers).

International Journal of ChemTech Research 2(1), 646-652 (2010). TLC on silica gel with toluene - methanol - triethylamine 9:3:1 with chamber saturation for 30 min. The hRf value was 71. Densitometric evaluation at 282 nm. The method was linear in the range of 100-2000 ng/band with r2 = 0.9973. The repeatability of sample application and measurement of peak area (%RSD, n=6) was 0.461 % and 0.363 %. The %RSD for intra-day and inter-day variation was 0.752-0.961 % and 0.848-1.082 % respectively. The LOD and LOQ was 10 and 50 ng/zone, respectively. The average recovery was 99.5 %. The samples were subjected to stress conditions (acid, base, oxidative, thermal) and all degradation products were well resolved from the main compound. The method was found suitable for stability studies and for routine analysis of the drug in biological fluids.

J. Liq. Chromatogr. Relat. Technol. 33, 1038-1046 (2010). TLC of nicotinic acid and methyl, ethyl, isopropyl, butyl, hexyl, and benzyl nicotinate (heated for 1 to 7 h at 120 °C) on silica gel pre-washed with methanol using methanol - benzene (for nicotinic acid) and acetone - hexane 2:3 for nicotinic acid esters. Quantitative determination by densitometric absorbance measurement at the respective absorption maximums (263 nm for nicotinic acid, 220-222 nm for nicotinic acid esters). The hRf of nicotinic acid was 44, and of methyl, ethyl, isopropyl, butyl, hexyl, and benzyl nicotinate 48, 46, 51, 54, 56, and 44, respectively.)

Phytochem. Anal. 22, 36-41 (2011). TLC of kutkoside (1) and picroside-I (2) in the kutki extract (Picrorhiza kurroa) on silica gel with ethyl acetate - methanol - glacial acetic acid - formic acid 25:5:1:1. Quantitative determination by absorbance measurement at 265 nm.The hRf of (1) was 42 and of (2) 61. The precision was 0.77 % and 1.01 % for (1) and (2), respectively. Linearity was between 80-480 ng/zone for both substances. Detection and quantification limits were 24 and 79 ng/zone for both. The intra-day and inter-day precisions were 0.4 % and 0.3 % (n=3) respectively. The recovery for (1) was 96.5 % and for (2) 96.0 %, respectively. The results were comparable with those obtained by HPLC.

Journal of Pharmacy Research 3(8), 1997-1999 (2010). TLC on silica gel (plates pre-washed with methanol) with methanol - water - acetic acid 80:20:1. The hRf value of ranitidine HCl was 27 and of dicyclomine HCl was 67. Derivatization by exposure to iodine vapor. Densitometric evaluation at 410 nm. The method was linear in the range of 400-2400 ng/band for dicyclomine hydrochloride and 150-900 ng/band for ranitidine hydrochloride. The mean recovery was 98.8 ± 0.5 % for ranitidine HCl and 99.1 ± 0.8 % for dicyclomine HCl.

CBS 106, 7-10 (2011). HPTLC of sucralose on silica gel (pre-washed by development with methanol, followed by drying at 100 °C for 15 min) with isopropyl acetate – methanol – water 15:3:1 up to 60 mm (migration time 15 min). Detection by dipping in aniline diphenylamine o-phosphoric acid reagent followed by heating at 120 °C for 20 min, evaluation under white light and UV 366 nm. Quantitative determination by absorbance measurement at 400 nm. Via the TLC-MS Interface the respective zones were eluted and transferred into a single-quadrupole mass spectrometer. Electrospray ionization mass spectra were recorded in full scan mode. The recovery of sucralose in drinking water was 84 ± 7 % (n=3). The limit of detection was 6 ng/band. The calibration curve (10-300 ng/band, r=0.9999, 1.3 %RSD) was suited to analyze sucralose at concentrations of 0.1-5 µg/L.

International J. Pharm. & Tech 2(2), 285-292 (2010). TLC of gallic acid in acetone extracts of bark powder of Acacia nilotica on silica gel with toluene – ethyl acetate – formic acid 15:10:2. The hRf value of gallic acid was 36. Quantitative determination by absorbance measurement at 280 nm. The method was linear in the range of 100-350 ng/band with recovery of 97.5 %.