62nd Indian Pharmaceutical Congress Abstract No. F-262 (2010). TLC of carbamazepine on silica gel with ethyl acetate – toluene – methanol 5:4:1. Quantitative determination by absorbance measurement at 285 nm. The hRf value was 47. The linearity was in the range of 100-600 ng/zone with r2 = 0.9995. The limit of detection was found to be 17 ng/zone, whereas the limit of quantitation was found to be 50 ng/zone.

J. Pharm. Biomed. Anal. 54, 422-425 (2011). HPTLC of aloin in several aloe dried extracts and related commercial formulations on silica gel with ethyl formate – methanol – water 200:29:20. Evaluation under 254 nm. Detection by immersion in 10 % H3BO3 in methanol, followed by heating at 110 °C for 10 min. Quantitative determination by fluorescence measurement at 365/K540 nm.

Acta Chromatographica 22 (2), 173-187 (2010), DOI:10.1556/AChrom.22.2010.2.2. HPTLC on silica gel with methanol – carbon tetrachloride – ethyl acetate – glacial acetic acid 80:636:280:4. The hRf values were 45 and 30 for atorvastatin calcium and losartan potassium, respectively. Quantification by densitometry at 238 nm. Linearity was in the range of 50–500 ng/band for each substance. The recoveries were 100.6 % and 100.5 % for atorvastatin calcium and losartan potassium, respectively. No interference from excipients was observed. The results were compared statistically using a paired t-test with results by an RP-HPLC method. Both methods provided comparable results.

Ind. J. Pharma. Sci. 72(5), 629-632 (2010). TLC of almotriptan malate on silica gel aluminum foil with butanol - acetic acid - water 3:1:1. Quantitative determination by densitometry in absorbance mode at 300 nm. The calibration curve was linear over the range of 100-700 ng/band for almotriptan malate. The method was successfully applied to the analysis of drug in a pharmaceutical form. 

International Journal of PharmTech Research 3(2), 986-999 (2011). TLC of methanolic extracts of Haritaki and gallic acid and rutin as markers on silica gel with toluene - ethyl acetate - formic acid 3:6:1 for gallic acid and chloroform - ethyl acetate - methanol - formic acid 7:10:1:2 for rutin. Quantitative determination by densitometry in absorbance mode at 280 nm for gallic acid and 254 nm for rutin. The method was linear in the range of 100-500 ng/band for gallic acid and 1000-5000 ng/band for rutin. The recovery was 99.1 % for gallic acid and 97.9 % for rutin. The LOD and LOQ of gallic acid was 71 and 213 ng/zone and of rutin 63 and 189 ng/zone.

J. Planar Chromatogr. 24, 394-399 (2011). TLC of leave extracts and six flavonoids as markers (vitexin, isovitexin, orientin, isoorientin, quercetin, and tricin) on silica gel, prewashed with methanol and methylene chloride, with methanol - ethyl acetate - acetone - methylene chloride in different ratios using automated multiple development. The developed plate was dried in air for 2 h and sprayed with 1 % aluminum trichloride in ethanol. Then the plate was left for 2 h for derivatization in a glass drying chamber. Quantitative determination by densitometry at 366 nm. The hRf values of the six marker flavonoids were 22, 31, 38, 45, 57, and 88, respectively. Linearity was between 175 and 1750 ng/band. Instrument precision (n = 10) was between 0.2-0.9 %. The repeatability for standards and samples (n = 9), was 0.7 and 0.5, 0.8 and 0.5, 0.8 and 0.5, 0.8 and 0.4, 1.3 and 0.7, 1.1 and 0.3 % for isoorientin, orientin, isovitexin, vitexin, quercetin, and tricin, respectively. The limits of detection were 35, 40, 35, 50, 80, and 20 ng/zone for isoorientin, orientin, isovitexin, vitexin, quercetin, and tricin, respectively. The intra-day and inter-day precision was between 0.1-2.9 % and 0.3-2.4 % for all six marker flavonoids.

J. Planar Chromatogr. 24, 35-39 (2011). HPTLC of olmesartan medoxomil (OLM) and hydrochlorothiazide (HTZ) on silica gel with chloroform - methanol - formic acid 16:3:1 in a chamber saturated for 1 h. Detection under UV light at 254 nm. Quantitative determination by densitometry at 260 nm for olmesartan medoxomil and 272 nm for hydrochlorothiazide. Linearity was between 0.05-1 mg/mL. Average recovery was 100.3 % and 99.9 % for OLM and HTZ, respectively. The LOD was 138 and 137 ng/zone for OLM and HTZ, respectively, and the LOQ was 459 and 456 ng/zone for OLM and HTZ, respectively. The intra-day and inter-day precision (%RSD, n = 9) was 1.2 and 1.4 % for OLM and 1.1 and 1.3 % for HTZ.

J. Planar Chromatogr. 24, 253-256 (2011). HPTLC of yohimbine on silica gel, prewashed with methanol, with toluene - ethyl acetate - diethyl amine 7:2:1 in a twin trough chamber saturated with mobile phase for 10 min at 25 +/- 2 °C. Quantitative determination by densitometry in absorbance mode at 285 nm. Linearity was between 400 and 1200 ng/band. The hRf value was 39. The repeatability as system precision and method precision (n = 6) was 0.9 and 0.8 % CV. The limit of detection and quantification was 80 ng and 260 ng. The instrument precision (n = 6), intra-day and inter-day precision (n = 3, %RSD) were 0.2, 0.1, and 0.1 %, respectively.