J. Ethnopharmacol. 197, 165-172 (2017). HPTLC of arjunolic acid (1), arjunetin (2), berberin (3), piperine (4), resveratrol (5) and withaferin-A (6) in Ayurvedic formulation on silica gel with ethyl acetate – toluene – formic acid – acetic acid 6:3:5:1 for (1), n-butanol – glacial acetic acid – water 12:3:4 for (2), toluene – ethyl acetate – diethylether 6:3:1 for (3), chloroform – ethyl acetate – formic acid 25:10:1 for (4) and chloroform – methanol 19:1 for (5) and (6). Detection of (1-4) by spraying with anisaldehyde sulfuric acid reagent. Quantitative determination by absorbance measurement at 690 nm for (1) and (2), 366 nm for (3), 330 nm for (4), 307 nm for (5) and 225 nm for (5) and (6). The hRF values for (1-6) were 67, 31, 58, 24, 32 and 37, respectively.

Phytochem. Anal. 28, 87-92 (2017). HPTLC fingerprint of the aerial parts of Justicia secunda on silica gel with chloroform – methanol – water 6:4:1. Detection by dipping into 200 mL enzyme solution (2000 U of alpha-D-glucosidase dissolved in 200 mL buffer solution prepared with 10 g sodium acetate in 250 mL double-distilled water, pH 7.5 with acetic acid), followed by incubation for 1 h in a humid desiccator and dipping into 200 mL of substrate solution (2 mg/mL 2-naphthyl-alpha-D-glucopyranoside in 50 % aqueous ethanol and 2.5 mg/mL Fast blue salt B in double-distilled water, mixed 1:1 before applying). Detection under UV 366 nm.

J. Chromatogr. A 1482, 97-108 (2017). For the analysis of flavan-3-ols and proanthocyanidins in crude extracts of Japanese knotweed (Fallopia japonica Houtt.) rhizomes, the sensitivity of HPTLC-MS methods was improved by using two pre-developments of the silica gel layer, firstly with methanol – formic acid 10:1, and secondly with acetonitrile – methanol 2:1. HPTLC on silica gel and silica gel MS grade with toluene – acetone – formic acid 3:3:1; 6:6:1; 3:6:1, and dichloromethane – acetone – formic acid 10:10:1. Detection by derivatization with 4-dimethylaminocinnamaldehyde (DMACA) reagent and evaluation under white light allowed for the identification of flavan-3-ols and B-type proanthocyanidins from monomers up to decamers. Tentative identification of trimers, trimer gallates, tetramer gallates, pentamers, pentamer gallates, hexamers, hexamer gallates, heptamers, octamers, nonamers and decamers in Japanese knotweed rhizomes. Simultaneous identification of stilbenes (resveratrol, piceatannol hexoside, piceid) and anthraquinones (emodin, emodin-O-hexoside, emodin-O-(acetyl)-hexoside and emodin-O-(6′-O-malonyl)-hexoside).

J. Planar Chromatogr. 31, 129-134 (2018). HPTLC of hydroxysafflor yellow A in safflower on silica gel with 3.6 % hydrochloric acid – methanol – ethyl acetate 7:3:1. Quantitative determination by absorbance measurement at 399 nm. The hRf value for hydroxysafflor yellow A was 60. Linearity (starting from LOD) was in the range of 62-793 ng/zone with r=0.9991. The intermediate precision was below 3 % (n=6). The LOD and LOQ were 59 and 169 ng/zone, respectively. Recovery was between 96 and 102 %.

CBS 120, 14-15 (2018). The drugs cefixime trihydrate (CEFI) and azithromycin dihydrate (AZI) were subjected to hydrolytic degradation (with water, 0.5 N HCl or 0.5 N NaOH), oxidative degradation (with 3 % and 30 % hydrogen peroxide), thermal degradation (heated at 100 °C and 200 °C for 1 h and 2 h) and photolytic degradation (exposed to fluorescent cold white light and UV light). HPTLC of CEFI, AZI, and the degradation samples on silica gel with ethyl acetate – methanol – acetone –_x000D_ toluene – ammonia 2:10:14:1:1 to the migration distance of 80 mm. Detection of AZI by immersion into sulfuric acid reagent (1:4 in ethanol) and heating at 100 °C for 5 min. Evaluation under UV 254 nm, UV 366 nm, and white light. Quantitative determination by absorbance measurement at 235 nm for CEFI and 530 nm for AZI. Linearity was in the range of 500–2500 ng/zone for CEFI and 50–250 ng/zone for AZI. The LOD and LOQ (ng/zone) for CEFI were 58 and 175, respectively, and for AZI 3 and 10, respectively. Precision (%RSD) was <2 %. In the forced degradation studies, CEFI degraded to 4 major products under different stress conditions. AZI showed only one additional peak upon acid and neutral hydrolysis.

J. Planar Chromatogr. 31, 497-504 (2018). HPTLC of chloroacetamide derivatives on RP-18 with ethanol and tetrahydrofuran as organic modifiers with water. Lipophilicity was examined by cluster analysis and principal component analysis. The obtained chromatographic parameters of the examined acetamides were correlated with the standard measure of lipophilicity, log P.

Phytochem. Anal. 29, 452-462 (2018). HPTLC of apigenin(1), luteolin (2), kaempferol (3), quercetin (4), kaempferol‐3‐O‐glucoside (5), quercetin‐3‐O‐glucoside (6), isorhamnetin‐3‐O‐neohesperidoside (7) and rutin (8) in the fruits and aerial parts of Foeniculum vulgare (fennel), Pimpinella anisum (anise), Carum carvi (caraway), Cuminum cyminum (cumin), Coriandrum sativum (coriander), Apium graveolens (celery), Petroselinum crispum (parsley), and Anethum graveolens (dill) on silica gel with ethyl acetate – methanol – water – acetic acid 3:1:1:1. Quantitative determination by absorbance measurement at 254 nm. Heat maps and hierarchical clustering were performed for image processing. The hRF values for (1) to (8) were 97, 90, 83, 73, 30, 17, 7 and 2, respectively. LOD and LOQ were 54 and 166 ng/zone for (1), 52 and 157 ng/zone for (2), 58 and 177 ng/zone for (3), 37 and 112 ng/zone for (4), 57 and 172 ng/zone for (5), 54 and 164 ng/zone for (6), 55 and 169 ng/zone for (7) and 58 and 178 ng/zone for (8), respectively. The intermediate precision was <2 % (n=6). Average recovery was 98.4 % for (1), 92.3 % for (2), 95.3 % for (3), 96.8 % for (4), 94.5 % for (5), 95.6 % for (6), 95.1 % for (7) and 97.3 % for (8).

J. Sep. Sci. 41, 3553-3560 (2018). HPTLC of sofosbuvir (1), daclatasvir (2), and ledipasvir (3) on silica gel with methylene – chloride – methanol – ethyl acetate – ammonia (25 %) 6:1:4:1. Quantitative determination by absorbance measurement at 275 nm. The hRF values for (1) to (3) were 27, 50 and 68, respectively. Linearity ranged between 100-3000 ng/zone for (1) and (2) and 50-3000 ng/zone for (3). LOD and LOQ were 23 and 68 ng/mL for (1), 32 and 96 ng/mL for (2) and 16 and 48 ng/mL for (3). The intermediate precision was <2 % (n=3). Average recovery was 99.5 % for (1), 99.5 % for (2) and 99.7 % for (3).