I. Isolation of a substance from marine algae with antiviral effect. Herba Hungarica 30, 47-53 (1991). TLC of antibiotic substance on silica with butanol - ethanol - chloroform - NH3 4:5:2:5 or MEK - ethanol - NH3 1:1:1. Detection by spraying with sulfuric acid. Quantification by densitometry.

J. AOAC Int. 77, 1101-1104 (1994). TLC of chloramphenicol on silica with 1-propanol - hexane 3:17. Visualization by spraying with stannous chloride solution, heating at 110 °C for 15 min, spraying with 2N sodium hydroxide solution, then with buffer solution pH 8.3 followed by heating at 110 °C for 5 min and spraying with fluorescamine solution. Examination under UV after placing in dark for 15 min. Detection limit 10 ng/kg.

Proc 9th Internat. Symp. Instr. Chromatog. Interlaken, April 9.-11. 129-146 (1997). In pharmaceutical analysis TLC can be used for identification, purity testing, stability testing, assay and even to study metabolism. For each of these applications examples show how well TLC may perform in the analysis of antibiotics. Comparison with LC is made. Example for identification: separation of (30) cephalosporins on silanized silica with seven different mobile phases, two of which are sufficient for complete identification. Identification of chlorotetracycline, demeclocycline, doxycycline, metacycline, minocycline, oxytetracycline and tetracycline on impregnated with a 100 g/L solution of edetate with a pH of 7.0, 8.0 or 9.0 with dichloromethane - methanol - water 59:35:6. Detection under UV 365 nm. Determination of neomycin C in neomycin on silica with methanol - 20% sodium chloride solution. Visualization by reaction with ninhydrin. Quantification by fluorescence scanning. Purity control and assay of minocycline and determination of erythromycin are also mentioned.

Part V. Quantitation and evaluation of several classes of antibiotics. J. Planar Chromatogr. 12, 280-287 (1999). HPTLC of antibiotics (amikacin, gentamycin, tobramycin, ciprofloxacin, norfloxacin, ofloxacin, aztreonam, clavalinic acid, cefotetan, erythromycin, imipenem, vancomycin, rifampin, trimethorprim, chloramphenicol, nitrocefin, clindamycin, tetracycline, sulfamethazole) on hydrocarbon-impregnated silica gel without prior elution. Standards and samples were dissolved in water and spotted on to the plate, where they remained as single spots centered around the point of application. Direct quantitation by densitometry at different wavelengths.

Anal. Chem. 75, 2493-2498 (2003). TLC of clindamycin, sildenafil, ferrocene and biferrocene on RP-18 on small channels cut on a Teflon plate with methanol - dichloromethane and on silica gel coated on alumina plate with hexane. The interfaces are two bound optical fibers inserted into the RP-18-bonded particles at the exit of a small TLC channel and a small commercial TLC strip with a sharpened tip. Detailed description of the design can be found. Organic mixtures were separated succesfully and detected on-line using the TLC/ES-MS techniques.

J. Planar Chromatogr. 19, 62-67 (2006). TLC of erythromycin, troleandomycin, tylosin, rifamycin B, and rifampicin on RP18 with a wide range (from 0 to 100 %) of mixtures of alcohols with dimethyl sulfoxide or hexamethyldisiloxan in pre-saturated chambers. Visualization by spraying with a 1:4 mixture of concentrated sulfuric acid and methanol followed by heating in an incubator at 120 °C for 10 min.

CBS 98, 5-7 (2007). HPTLC of gatifloxacin on silica gel in a saturated twin-trough chamber with n-propanol - methanol - ammonia 25% 50:10:9 over 80 mm. Quantitative determination by absorbance measurement at 292 nm. The hRf value of gatifloxacin was 60 and selectivity regardnig matrix was given. Linearity was between 400 and 1200 ng/band. The intraday and interday precision both were below 0.03 %. The limit of detection and quantification was 2.7 and 8.3 ng/zone, respectively. Recovery was between 99.2 and 101.9 %. The HPTLC method was suited to study gatifloxacin stability under different stress conditions according to ICH guidelines (acid, base, heat, oxidation, photostability).

Chinese J. Pharm. Anal. 26 (2), 221-224 (2006). HPTLC of gentamycin and related compounds on silica gel with chloroform – methanol – 25 % ammonia 5:7:6. The main compound is well separated from the impurities. Quantification by densitometry at 485 nm. Linearity was between 4.0 – 40 ng/spot (r2 = 0.99) and the limit of detection was at the low ng level.