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. 3, 370-375 (1990). The influence of derivatization technique, plate drying, reagent concentration, and selected detector parameters on the densitometric determination of flavonoids was investigated using the two main flavonoid glucoronides from Malva silvestris leaves as an example. Postchromatographic derivatization by dipping successively in 0.5 % NST (2-aminoethyl diphenylborinate) in ethyl acetate and 5 % polyethylene glycol in dichloromethane. The method is also appropriate for the quantitative determination of flavonoids.

Planar Chromatogr. 3 79-81 (1990). TLC separation of lanthanides and other elements (Ce, Nd, Sm, Gd, Ho, Yb, Y, Ti, V, Zr, Th, U) on silica impregnated with different concentrations of H2MEHP, using different concentrations of nitric acid (0.05 - 3.0 M). Detection by spraying with 1% solution of 8-hydroxyquinoline in ethanol, followed by exposure to NH3.

Chinese J. Chromatogr. 10, 169-170 (1992). TLC of gangliosides on silica with 1) chloroform – methanol – water 11:9:2, 2) acetic acid – propanol – chloroform – methanol – water 5:4:4:4:3, 3) chloroform – methanol – NH3 40:32:7. Detection by spraying with a solution containing 0.2 g resorcinol, water 10 mL, hydrochloric acid (36 %) 80 mL, 0.1 mol/L copper sulfate, and heating for 15 – 20 min at 110 °C.

Chinese J. Pharm. Anal. (Yaowu Fenxi Zazhi) 12, 159-162 (1992). TLC of ß-eudesmol, magnolol and honokiol on silica with chloroform – benzene – ethyl acetate – methanol 10:8:2:1. Detection by exposure to iodine vapor. Quantification by GC.

J. Planar Chromatogr. 5, 316-318 (1992). TLC of ecdysteroids (ecdysone, 2-dioxyecdysone, ponasterone A, decrysterone, cyasterone, 20-hydroxyecdysone, makisterone A) after “overspotting” a methanolic solution (2 µL of 10 mg/mL solution) of butyl-, phenyl-, or aminophenylboronic acid on RP-18 silica with methanol - water 7:3. Detection under UV 254 nm.

J. West China Univ. Med. Sci. (Huaxi Yike Daxue Xuebao) 24, 194-197 (1993). Presentation of a novel stable fluorescent reagent CGE(N) for the detection of compounds containing amino groups with TLC detection of glucine as example. Fluorescent excitation at 277 nm and emission wavelength of the spot at 356 nm, resp. Detection limit of 240 ng/spot.

Indian Drugs 41 (3), 149-152 (2004). HPTLC on silica gel with toluene - ethyl acetate 1:24. Quantitative determination by absorbance measurement at 260 nm. The linearity range is 100-500 µg/µL and recovery is 100.7 %. The method was validated and compared with HPLC. The results were comparable. Advantages of HPTLC in terms of handling many samples. Thus, a simple, fast and precise HPTLC method was developed for quantification of ebastine in tablets.