62nd Indian Pharmaceutical Congress Abstract No. F-253 (2010). TLC of ambroxol hydrochloride and doxophylline on silica gel with n-butanol – toluene – ethyl acetate – 25 % ammonia 50:30:20:1. The hRf values were 36 and 45 for doxophylline and ambroxol, respectively. Quantitative determination by absorbance measurement at 258 nm. The method was linear in the range of 300-1100 ng/band for ambroxol and 100-1100 ng/band for doxophylline.

62nd Indian Pharmaceutical Congress Abstract No. F-236 (2010). TLC of rupatadine formulation on silica gel with acetonitrile – water – formic acid 50:50:3. The hRf value was 67. Quantitative determination by absorbance measurement at 263 nm. The method was linear in the range of 1-20 µg/band.

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.

Abstracts, 42nd Middle Atlantic Regional Meeting of the American Chemical Society, College Park MD, USA, May 21-24 (2011). The four TLC methods for acetaminophen, acetylsalicylic acid, ibuprofen, and chlorpheniramine maleate contained in the Compendium of methods developed by A.S. Kenyon and T.P. Layloff at the US FDA for use in countries with limited resources were transferred to quantitative HPTLC. The used sample preparation methods provide suitable calibration curves covering the range of 70-130 % of the label value of the products. Quantitative determination by absorbance measurement at 254 nm.

J. AOAC Int. 93, 754-764 (2010). The review describes analytical methods for drug substances, formulations, and clinical samples analyzed and validated by HPTLC during the period 1996-2009. Procedures, materials, and instrumentation for the different steps in the chromatographic procedure and validation of results are given; application to bulk drugs, formulations, stability studies, biological samples (e.g., urine and plasma), and hydrophobicity studies; and prospects for the future use of HPTLC for drug analysis are described. The sections cover the experimental procedures (sample preparation, stationary phases, mobile phases, application of standards and samples, chromatogram development, detection, documentation of chromatograms, densitometric quantitative analysis), determination of hydrophobicity, confirmation of zone identity, method validation, chiral separations, micropreparative layer chromatography, applications of HPTLC-densitometry, and future prospects for HPTLC in drug analysis. 155 references are reviewed.

J. Planar Chromatogr. 24, 211-213 (2011). HPTLC of exo-polysaccharides from bacterial fermentation and a series of mono-, oligo-, and polysaccharide reference solutions on silica gel with chloroform - toluene - 35 % formic acid - methanol 10:2:2:7 in a twin-trough chamber saturated for 1 h. Detection of starch-type polysaccharides by placing the plate into a twin-trough chamber saturated with iodine vapor. After drying determination by densitometry in absorbance mode at 400 nm. The plates were then immersed for 1 min in a solution of 10 % concentrated sulfuric acid in n-propanol - toluene 1:1, followed by heating at 115 °C for 10 min. The zones were evaluated visually and densitometrically at 400 nm.

J. Planar Chromatogr. 24, 524-528 (2011). TLC of cefixime on silica gel with toluene - ethyl acetate - formic acid - water 5:29:11:5 with chamber saturation for 30 min at 25 +/- 2 °C. The hRf value was 54. Quantitative determination by densitometry in absorbance mode at 293 nm. Linearity was between 500 and 1500 ng. The repeatability (%RSD) was below 2 %. The limit of detection and the limit of quantification was 9 and 42 ng/zone, respectively. The recovery was between 98.9-100.3 %.

J. Planar Chromatogr. 23, 323-325 (2010). HPTLC of taraxerol on silica gel with hexane - ethyl acetate 9:1 in a saturated twin-trough chamber. Detection by spraying with anisaldehyde - sulfuric acid reagent followed by heating for 5 min at 80 °C. Quantitative determination by absorbance measurement at 540 nm. The average recovery was between 99.6 and 100.3 % with %RSD less than 2 %. For both intra-day and inter-day precision %RSD was less than 2 %. The LOD and LOQ were 47 and 140 ng/band, respectively. The linearity range was 0.5-2.5 µg/band. The hRf value of taraxerol was 22.