Indian Drugs 48(4), 49-55 (2011). HPTLC of hydrochlorothiazide (HCZ), amlodipine besylate (AMB) and valsartan (VAL) on silica gel with ethyl acetate - methanol - 10 % ammonia 17:4:2. The hRf value was 26 for AMB, 34 for VAL and 82 for HCZ. The linearity range was 100-700 ng/band for VAL and HCZ and 50-400 ng/band for AMB.

Anal. Chim. Acta 633 (2) 188-196 (2009). HPTLC of lycorine and galanthamine from Narcissus jonquilla ‘Pipit’ on silica gel with chloroform - methanol - 25 % ammonia 18:1:1. Quantitative evaluation by absorbance measurement at 207 nm. The correlation coefficients were r=0.9882 and 0.9908, respectively, for the mean values of galanthamine and lycorine. Investigation of different extraction solvents showed that extraction with methanol and 1 % tartaric acid in methanol at default conditions (120 °C, p = 60 bar, time: 10 min, one static cycle) provide the highest yields of total alkaloids, whereas for toluene the lowest amounts were measured. Lycorine to galanthamine mean ratios were dependant on the type of solvent used, and in toluene galanthamine and related alkaloids were preferably extracted.

Planta Med. 77, 548 (2011). HPTLC of forskolin and extracts from rhizomes of Coleus forskohlii on silica gel with toluene - methanol 12:1. The hRf value of forskolin was 27. Anisaldehyde-sulfuric acid reagent was used for spraying followed by heating of the plate at 105 °C for 5 min. Quantitative determination by densitometric scanning in absorbance mode at 545 nm.

J. Ethnopharmacol. 137, 341-344 (2011). HPTLC of quercetin (1) and kaempferol (2) in the leaves of Argyreia speciosa on silica gel with toluene - ethyl acetate 93:7. Quantitative determination by absorbance measurement at 254 nm. The hRf values of (1) and (2) were 32 and 75, respectively and their amount was found to be 0.6 % and 0.2 %, respectively.

J. AOAC Int. 93, 783-786 (2010). HPTLC of etoricoxib (ETO) and thiocolchicoside (THIO) on silica gel (prewashed with methanol) with ethyl acetate - methanol 4:1 in a twin-trough chamber after preconditioning for 20 min. Quantitative determination by absorbance measurement at 290 nm. The calibration curve was linear over a range of 50-250 and 100-500 ng/band with correlation coefficients of 0.9948 and 0.9958 for ETO and THIO, respectively. LOD and LOQ were 11 and 33 ng/band for ETO and 25 and 76 ng/band for THIO. %RSD values were found to be 0.5 and 0.8 % for ETO and THIO for intra-day variations, while inter-day variations were 1.2 and 1.0 %, respectively. The recovery for ETO was between 100.2-101.1 % and for THIO 98.7-100.4 %.

J. Planar Chromatogr. 23, 343-347 (2010). TLC and HPTLC of (derivatized) sulfide ions on silica gel with dichloromethane - methanol - diethyl ether - 25 % ammonia 40:5:5:1 in a horizontal chamber saturated for 20 min. Detection by using the methylene blue method, i.e. production of methylene blue by oxidative coupling of sulfide with N,N-dimethyl-p-phenylenediamine in the presence of iron(III) ions in acidic medium. Quantitative determination by absorbance measurement at 660 nm (method I), or analysis by TLSee software (method II). Response for both was a linear function in the concentration range of 20-100 pmol/zone. The LOD and LOQ were 10 pmol/zone (3.2 mg/L) and 20 pmol/zone (6.4 mg/L). The repeatability of both methods (%RSD) was 1.9-4.2 % for method I and 1.5-3.9 % for method II.

J. of Chromatogr. A 1248, 169-177 (2012). Purified oligomers of hyalobiuronic acid are indispensable tools to elucidate the physiological and pathophysiological role of hyaluronan degradation by various hyaluronidase isoenzymes. Establishment and validation of a novel sensitive, convenient, rapid, and cost-effective HPTLC method for the qualitative and quantitative analysis of small saturated hyaluronan oligosaccharides consisting of 2–4 hyalobiuronic acid moieties. HPTLC on amino phase with 1-butanol - formic acid - water 3:5:2 or 3:4:1. Detection 1) by spraying with orcinol in various concentrations of sulfuric acid; 2) by dipping into the reagent of orcinol in 10 % sulfuric acid and Morgan–Elson reagent; 3) by illuminating with white light and UV 366 nm after heating. The simple reagent-free in situ derivatization of 3) resulted in a detection limit of 7–19 pmol/band and LOQ of 37–71 pmol/band depending on the analyzed saturated oligosaccharide. Identification of the analytes by TLC-ESI-MS. The validated HPTLC method, as an alternative to sequential techniques such as HPLC and CE, can easily be automated and is applicable to the analysis of multiple samples in parallel.

J. Planar Chromatogr. 25, 77-80 (2012). HPTLC of gemcitabine on silica gel with toluene - methanol - chloroform 6:6:5. Quantitative determination by absorbance measurement at 268 nm. The hRf value of gemcitabine was 48. Linearity was in the range of 500-3000 ng/band. Intraday and interday precisions (%RSD) were 1.4-1.6 % and 1.6-1.8 %, respectively. Recovery was found to be in the range of 98.3-101.8 %.