J. Liq. Chromatogr. Relat. Technol. 38, 1731-1739 (2015). HPTLC of asenapine maleate in pharmaceutical formulations on silica gel with methanol. Quantitative determination by absorbance measurement at 235 nm. The hRF value for asenapine was 43. Linearity was in the range of 300-1800 ng/zone. LOD and LOQ were 39 and 119 ng/zone, respectively. The intermediate precision was below 0.2 % (n=3). Recovery was in the range of 99-102 %. Results were comparable to those obtained by HPLC.

J. Planar Chromatogr. 29, 287-298 (2016). HPTLC of 34 structurally diverse drugs on RP-18 with acetonitrile – pH 7.4 phosphate buffered saline 7:3. Detection under UV 254 nm. Molecular descriptors were investigated to assign the compounds to two clusters: central nervous system active (CNS+) or inactive (CNS-) describing the ability of the compounds to penetrate the brain.

J. Planar Chromatogr. 29, 99-107 (2016). Review of the application of TLC for the analysis of neutral and polar lipids found in parasite-infected and noninfected snails. Different aspects of the TLC procedure such as sample preparation, sample and standard application, layers and mobile phases, detection and quantification were reviewed. Compared to earlier reviews, the authors included lipophilic pigments as well as valuable information on numerous species of gastropod molluscs.

J. Planar Chromatogr. 29, 140-144 (2016). HPTLC of atovaquone (1) and proguanil (2) in tablets on silica gel with toluene – methanol – glacial acetic acid 40:10:1. Quantitative determination by absorbance measurement at 254 nm. The hRF values for (1) and (2) were 80 and 22, respectively. Linearity was in the range of 200-2000 ng/zone for (1) and 100-1000 ng/zone for (2). Intermediate precisions were below 1 %. The LOD and LOQ were 41 and 123 ng/zone for (1) and 31 and 94 ng/zone for (2), respectively. Recovery was in the range of 99.5-100.7 % for (1) and 100.1-100.8 % for (2).

J. Planar Chromatogr. 29, 132-139 (2016). HPTLC of ambroxol hydrochloride (1) and doxofylline (2) on silica gel with ether – n-butanol – ammonia 90:9:1. Quantitative determination by absorbance measurement at 276 nm. The hRF values for (1) and (2) were 74 and 41, respectively. Linearity was between 20-100 ng/zone for (1) and 100-500 ng/zone for (2). The intermediate precision was below 1 % (n=3). The LOD and LOQ for (1) and (2) was 1 and 4 ng/zone and 31 and 93 ng/zone, respectively. Recovery ranged between 99.3-101.1 % for (1) and 97.8-101.2 % for (2).

Planta Medica 82 (15), 1374-1380 (2016). To monitor the subfractionation with methanol on cyclodextrin of a butanol fraction of a methanolic Soxhlet extract of Tamaris Africana shoots, TLC on silica gel with n-butanol – acetic acid – water 12:3:5 and chloroform – methanol – water 70:30:3. Chromatograms were derivatized with Natural Product/PEG reagent and with cerium sulfate sulfuric acid reagent. From the obtained subfractions, flavonoids (three sulfated) and phenolic compounds (ferulic and veratric acid derivatives) could be further isolated.

J. Ethnopharmacol. 195, 10-19 (2017). HPTLC of mesembrine alkaloids (mesembrine, mesembrenone, mesembrinol, mesembrenol, epimesembranol, epimesembrenol) in the South African medicinal plant Sceletium tortuosum on silica gel with dichloromethane – methanol – 10 % ammonia 900:100:1. Quantitative determination by absorbance measurement at 280 nm. The LOD and LOQ were in the range of 18-31 ng/zone and 44-95 ng/zone, respectively.

J. Planar Chromatogr. 29, 380-387 (2016). HPTLC of metolazone (1) and spironolactone (2) on silica gel with ethyl acetate ‒ chloroform ‒ glacial acetic acid 50:50:1. Quantitative determination by absorbance measurement at 238 nm. The hRF values for (1) and (2) were 51 and 79, respectively. Linearities were between 50 and 300 ng/zone for (1) and 200 and 1200 ng/zone for (2). The intermediate precisions were below 1.3 % (n=6). The LODs and LOQs were 2 and 5 ng/zone for (1) and 5 and 16 ng/zone for (2). Average recoveries were 99.7 % for (1) and 99.7 % for (2). The developed method successfully separated drug substances from degradation products formed under various stress conditions.