60th Indian Pharmaceutical Congress PA-205, (2008). HPTLC of diacerein on silica gel with ethyl acetate - n-hexane - acetic acid 120:19:1. The hRf value was 32. Quantitative determination by absorbance measurement at 258 nm. The method was linear in the range of 50-250 ng/spot. The recovery was 96-103 %.

J. Liq. Chromatogr. Relat. Technol. 30, 2337-2344 (2007). TLC of pralidoxime and obidoxime on silica gel impregnated by an 18 hours continous development with 10 % paraffin oil in n-hexane in an unsaturated chamber. Lipophilicity was determined on paraffin coated TLC plates using 30 %, 40 %, 50 %, 60 %, 70 %, and 80 % aqueous methanol, each mixture containing 1 % ammonium hydroxide). Hydrophilicity was determined by using plain silica gel with 70 %, 80 %, and 90 % aqueous methanol and 100 % methanol, each mixture containing 1 % ammonium hydroxide. Detection under white light and under UV 254 nm.

Asian J. Chem. 19(6), 4286 - 4290 (2008). HPTLC of rofecoxib and tizanidine hydrochloride on silica gel with acetone - methanol 1:1. The method was linear in the range of 2200-3300 ng/spot and 180-260 ng/spot for rofecoxib and tizanidine respectively. The recovery was between 99.7 and 102.6 % for both compounds. The method was useful for the simultaneous estimation of the drug content in pure and tablet dosage form.

Asian J. Chem. 18(2), 1078-1084 (2006). TLC of nimesulide and diclofenac sodium on silica gel with n-hexane - ethyl acetate - chloroform - acetic acid 16:2:3:1. Quantitative determination by absorbance measurement at 256 nm. The hRf value of nimesulide was 3 and of diclofenac sodium 57. Linearity was between 1.0 and 3.2 µg/zone for nimesulide and 0.5 and 1.6 µg/zone for diclofenac sodium. The recoveries (by standard addition method) were in the range of 99.1 and 101.0 for both drugs. The proposed method is precise and accurate and can be used for routine analysis of nimesulide and diclofenac sodium capsule formulation.

Anal. Chim. Acta 577 (1), 46-51 (2006). HPTLC of trigonelline in herbal extracts and in pharmaceutical dosage forms on silica gel with n-propanol - methanol - water 4:1:4. Quantitative determination by absorbance measurement at 269 nm. Linearity was between 100 - 1200 ng/spot (via peak area) and the correlation coefficient was 0.9991. The trigonelline content of herbal extracts quantified and estimated from the formulation was found to be well within limits (± 5 %) of the labeled content of the formulations. The method is reproducible and selective for the estimation of trigonelline by statistical analysis of the data.

J. Chinese Trad. Patent Med. 30 (11), 1642-1646 (2008). TLC of Yinao pill extracts on silica gel with 1) toluene - ethyl acetate 9:1; 2) benzene - ethyl acetate 3:2; 3) toluene - ethyl acetate - formic acid 28:8:1. Detection 1) by spraying with 10 % phosphomolybdic acid in ethanol and heating at 105 ºC; 2) by spraying with 10 % sulfuric acid in ethanol and heating at 105 ºC.

Ind. J. of Pharma Sci. 70(6), 844-847 (2008). HPTLC of plumbagin in alcoholic root extracts of Plumbago indica and Plumbago zeylanica on silica gel with n-hexane - ethyl acetate 4:1. The hRf value of plumbagin was 67. Quantitative determination by absorbance measurement at 265 nm. Plumbago indica showed significantly higher plumbagin contents than P. zeylanica. The HPTLC method was the method of choice for simultaneous analysis of several samples, whereas the RP-HPLC method was very sensitive.

J. Chromatogr. A 1216 (25), 5057-5060 (2009). Paper chromatography of gamma-aminobutyric acid. The method consists of application, separation and detection and is clean, rapid, inexpensive and reproducible compared to the routine paper chromatography. The derivatization procedure with ninhydrin reagent was optimized regarding reagent concentration, derivatization temperature and time and Cu2+ concentration. Quantification of gamma-aminobutyric acid by combination of with Vis spectrophotometry. The limit of detection was 0.05 mg/mL and the linear range was from 0.5 to 20.0 mg/mL. The determination coefficient was r2 = 0.998. The method was accurate (%RSD < 2.6 %), and recoveries were 102.7-103.9 %.