and their herbal formulations. J. Planar Chromatogr. 31, 451-459 (2018). HPTLC of berberine chloride (1) and galangin (2) in Tinospora cordifolia M._x000D_ and Alpinia galanga on silica gel with toluene ‒ ethyl acetate ‒ formic acid 3:6:1. Quantitative determination by absorbance measurement at 267 nm. The hRF values for (1) and (2) were 17 and 82. Linearity was between 200 and 1200 ng/zone. LOD and LOQ were 28 and 86 ng/zone for (1) and 2 and 5 ng/zone for (2), respectively. The intermediate precision was <2 % (n=3). Recovery was between 97.5 and 102.6 % for (1) and (2).

J. Planar Chromatogr. 31, 383-388 (2018). HPTLC of cocaine hydrochloride (1) and levamisole hydrochloride (2) on silica gel with cyclohexane – toluene – diphenylamine 75:15:10. Quantitative determination by absorbance measurement at 230 nm. The hRF values for (1) and (2) were 24 and 48, respectively. Linearity was between 200 and 2400 ng/zone for (1) and 100 and 1200 ng/zone for (2). LOD and LOQ were 14 and 42 ng/zone for (1) and 6 and 19 ng/zone for (2), respectively. The intermediate precision was <2 % (n=6). Average recovery was 99.8 % for (1) and 99.9 % for (2).

Pharmacogn. Mag. 14, 377-383 (2018). HPTLC fingerprinting of Cichorium intybus seeds on silica gel with toluene – ethyl acetate – formic acid 3:4:1. The fingerprint was recorded under UV light at 254 and 366 nm.

J. Chromatogr. 438, 419-422 (1988).Reversed-phase and normal phase HPTLC of a number of ecdysteroids on octadecyl-bonded silica and silica with methanol - water systems. Detection by fluorescence quenching under UV 254 nm. Discussion of the effects of varying the water content on Rf values of ecdysone and 20-hydroxyecdysone on both layers.

Acta Chromatographica 14, 60-69 (2004). TLC on silica gel with 1-butanol - glacial acetic acid - water 3:1:1 with chamber saturation. Detection by spraying with ninhydrin reagent (0.3 g ninhydrin in 100 mL 1-butanol plus 2 mL glacial acetic acid), followed by heating at 110 ºC for several min. Quantification by densitometry at 495 nm. Validation of the accuracy by analysis of spiked blank and standard addition samples and precision by performing replicate analysis on a single day and on different days. Recoveries and RSD for spiked blank and standard addition samples were 98.8 % and 98.5 %, 1.92 % and 0.67 %, respectively. Discussion of use of the method for the routine quality control of nutritional supplements.

CBS 90, 10-11 (2003). HPTLC of periwinkle cell samples on prewashed silica gel with ethylacetate - diethylamine 9:1 in horizontal developing chamber over 25 mm. Detection by radiation with short-wave UV 254 nm. Quantitative determination by fluorescence measurement at 254 nm or 365 nm.

CBS 91, 12-13 (2003). HPTLC of flavonoids with tetrahydrofuran - toluene - formic acid - water 16:8:2:1, diterpenes with toluene - ethyl acetate 9:2, and iridoids with ethyl acetate - methanol - water 77:15:8 (with chamber saturation), in horizontal developing chamber over 52 mm. Detection of flavonoids by dipping warm plate in natural products reagent (0.5 % in ethyl acetate) followed by dipping in PEG 400 solution (5 % in dichloromethane), of diterpenes by dipping in 10 % methanolic sulfuric acid followed by heating at 105 °C, and iridoids by dipping in 4-dimethylaminobenzaldehyde reagent (1 % in 1 N methanolic HCl). Visual evaluation at 366 nm (flavonoids), white light (diterpenes), and white light with sharp cut filter 560 nm (iridoids). Stability of extracts was investigated under drastic stress conditions (acid, base, light, heat, humidity).

Indian J. Pharm. Sci. 66 (3), 306-308 (2004). HPTLC on silica gel with n-butanol - methanol - 6 M ammonia 5:1:2. Gatifloxacin showed Rf values of 0.47 ± 0.03. Quantitative determination by absorbance measurement at 292 nm. The method was validated in terms of linearity (400-1200 ng/spot), precision (intra-day variation 1.3 to 3.2 %, inter-day variation 3.9 to 5.0 %), accuracy (93.3 to 99.4 %), and specificity. The limit of detection and limit of quantification for gatifloxacin were found to be 10 ng/spot and 50 ng/spot respectively. The method is simple, sensitive, precise, and can be used for the routine quality control testing of marketed tablet formulations (400 mg).