J. Sep. Sci. 33, 1954-1958 (2010). HPTLC of clofentezine in medical herb extracts on silica gel with tetrahydrofuran - n-heptane 3:7. After drying for 20 min, the plate was turned 90 ° and developed with ethyl acetate - n-heptane 1:4. Quantitative determination by absorbance measurement at 254 nm. Limits of detection and quantification were 230 and 700 ng/zone respectively. The average recovery (by standard addition) was 55.8 %.

Anal. Chim. Acta 690 (2), 148-161 (2011). Chromatographic fingerprinting has been generally accepted as analytical method for the quality control of herbal medicines. This review describes the evolution of the regulations and guidelines on the quality control of herbal medicines, and reviews the established analytical techniques in TLC, HPLC, UHPLC, hydrophilic interaction chromatography, and GC. Emphasis is put on the most recent developments, such as miniaturized techniques, new stationary phases, analysis at high temperatures and multi-dimensional chromatography. The new chemometric data handling techniques are discussed.

62nd Indian Pharmaceutical Congress Abstract No. F-324 (2010). TLC of curcumin, piperine and quercetin in ayurvedic extract on silica gel with chloroform – toluene – ethyl acetate – methanol 4:4:1:1. The results obtained by the chromatographic method were comparable with a UV-VIS photometric method. All three compounds did not show any mutual interference.

62nd Indian Pharmaceutical Congress Abstract No. F-330 (2010). TLC of ofloxacin and ornidazole on silica gel with 1,4-dioxane – ethyl acetate – toluene – glacial acetic acid – water 5:5:3:2:2. The hRf values were 16 and 89 for ofloxacin and ornidazole, respectively. Quantitative determination by absorbance measurement at 287 nm. The results by TLC were comparable to the results by a spectophotometric method.

62nd Indian Pharmaceutical Congress Abstract No. F-301 (2010). TLC of brimonidine tartrate on silica gel with methanol – toluene – triethylamine 10:35:2. The hRf value was 48. Quantitative determination by absorbance measurement at 247 nm. The method was linear in the range of 100-600 ng/band. The sample was subjected to different stress conditions (acid, base, oxidative, thermal and photolytic). With the proposed method all the degradation products were well resolved from the drug.

62nd Indian Pharmaceutical Congress Abstract No. F-258 (2010). TLC of nebivolol HCl and hydrochlorothiazide on silica gel with methanol – chloroform – toluene – triethylamine 10:25:14:1. Quantitative determination by absorbance measurement at 284 nm. The hRf value of nebivolol was 78 and of hydrochlorthiazide 41. The method was linear in the range of 5-100 ng/band and 20-140 ng/band for nebivolol HCl and hydrochlorothiazide, respectively. Recovery was in the range of 98.8-100.0 % for both drugs.

Acta Chromatographica 22 (3), 433-443 (2010). HPTLC on silica gel with ethyl acetate – methanol - acetic acid 13:2:1. The hRf values were 46 and 78 for nebivolol hydrochloride and hydrochlorothiazide, respectively. Detection and quantification by densitometry at 280 and 270 nm for nebivolol hydrochloride and hydrochlorothiazide, respectively. The drugs were subjected to hydrolysis under acidic, basic, and neutral conditions, oxidation, heat, and photolysis as stress conditions. The drug showed degradation when subjected to oxidative stress and acidic conditions, which also affected the tablet sample substantially. However there was no interference of the drug peak by any of the degradation products. The method was therefore applied for stability testing of these drugs during stability studies.

J. Trad. Chinese Veterinary Med. (5), 53-55 (2010). TLC on silica gel with acetone – ethanol – hydrochloric acid 10:6:1. Detection by spraying with bismuth potassium iodide – 1 % FeCl3 in ethanol 5:1 and heating at 100 ºC. Quantitative determination of stachydrine by absorbance measurement at 510 nm. The precision was 3.7 %RSD within plate (n=8), and the stability of the measurement within 120 minutes was 4.5 %RSD (n=5). The linearity range was 3.2-38.3 µg/zone (r=0.997, n=6) and standard addition recovery was 96.6 % (RSD=2.0 %, n=6).