Rec. Nat. Prod. 3/4, 178-186 (2009). An HPTLC method has been reported for quantitative estimation of alpha-mangostin in fruit pericarp of Garcinia mangostana (Hypericaceae). HPTLC on silica gel with chloroform - methanol 9:1 in a saturated chamber (10 min). The plate was derivatized with anisaldehyde sulfuric acid reagent. Densitometric quantification at 382 nm. Alpha-mangostin was detected as a compact band with hRf value of 46. The method was linear in the range of 1-5 µg/band. The maximum yield of alpha-mangostin was obtained from the plant by hot extraction with methanol.

J. Chromatogr. A 1218 (19), 2722-2731 (2011). Review on the features of TLC in the different areas of pharmaceutical analysis, like in-process and intermediate control, illustrated by impurity testing of active ingredients and final products, as well as its application in pharmaceutical research and development. Based on examples reported in the last five years it is shown that TLC is still a very popular and frequently used analytical method in the pharmaceutical industry, although there is a tendency in current pharmacopoeias for favouring HPLC.

Quim. Nova. 34, 330-334 (2011). TLC of rosmarinic acid in preparations of Rosmarinus officinalis on silica gel with acetone – formic acid – methylene chloride 50:17:170. Detection under UV 366 nm. Quantitative determination by solid state differential pulse voltammetry (DPV). Linearity was between 0.694x10-3 to 0.526x10-3 mol/L. The limits of detection and quantification were 1.2x10-5 and 3.6x10-5 mol/L, respectively. The intermediate/interday/intraday precisions were 3.03 % and 2.2 %, respectively. Recovery (by standard addition) was 96.3 % for rosmarinic acid. The method presented high recovery levels compared to an HPLC method.

Der Pharma Chemica 2(3), 8-18 (2010). HPTLC of berberine on silica gel with methanol – acetic acid – water 8:1:1. The band corresponding to berberine showed an hRf value of 74. Quantitative determination by absorbance measurement at 350 nm. The method was linear in the range of 100-500 ng/band. Different samples analysed by the proposed method were found to contain 11.8-12.5 mg/g berberine. The recovery was between 98.0-100.3 %.

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. Sep. Sci. 34, 2397-2404 (2011). HPTLC of 23 newly synthesized N-substituted 2-alkylidene-4-oxothiazolidines on RP-18 with 1) methanol - water, 2) acetonitrile - water, and 3) tetrahydrofurane - water. A quantitative structure-retention relationship study allowed to understand the chromatographic behavior of similar compounds.

J. Planar Chromatogr. 24, 491-496 (2011). HPTLC of pentose, hexose and disaccharides in pharmaceutical formulations on silica with aqueous micellar bile salt, sodium deoxycholate in acetonitrile 1:5 with chamber saturation. This mobile phase provided the best separation of the 22 phases tested. Detection by spraying with ethanolic orcinol solution.

J. Liq. Chromatogr. Relat. Technol. 32, 3049-3055 (2009). HPTLC of cinoxacin (1), pipemidic acid (2), ofloxacin (3), and pefloxacin (4) on silica gel with buffer solution (pH 5.5) - methanol 4:1 and acetonitrile - water - acetic acid, 3:20:2. Detection by dipping into various visualization agents. The detection limits for (1) to (4) were 0.1, 0.1, 0.5, and 0.75 µg/zone, respectively. Best detection conditions for (1) and (2) were obtained by dipping in Janus blue and immediate evaluation, and for (3) and (4) by dipping in Cresol red followed by heating at 120 ºC for 10 min for (3) and (4).