J. Planar Chromatogr. 8, 238-240 (1995). TLC of sulfadiazine, sulfadimidine, sulfadimetoxine, sulfaquinoxaline on silica with ethyl acetate - dichloromethane 4:1 after preconcentration with acetonitrile. Detection after drying by spraying with a 0.02 % solution of fluorescamine in acetone, and observation under UV 366 nm.

J. Planar Chromatogr. 9, 138-141 (1996). HPTLC of cisapride and degradation products on silica with chloroform - methanol - toluene - acetic acid 70:30:60:3 in a chamber conditioned with the solvent system for 30 min. Quantification by densitometry at 307 nm. Detection limit 10 ng. Fast, sensitive, and specific TLC method.

J. Planar Chromatogr. 9, 388-390 (1996). HPTLC of verapamil hydrochloride (5-[N-(3,4-dimethoxyphenethyl)-methylamino]-2-(3,4-dimethoxyphenyl)-2-isopropylvaleronitrile monohydrochloride) on silica with ethyl acetate - methanol - water 100:13:10. Quantification by densitometry (absorbance) at 278 nm. Intraday and interday precision were 0.17-0.62% and 0.88-1.00%, respectively.

Proc. 9th Internat. Symp. Instr. Chromatogr., Interlaken, April 9.-11., 387-389 (1997). Elaboration of TLC methods that were reproducible and as simple as possible for the testing of finished products containing active substances from the Essential Drug List. The purposes of the search for suitable TLC conditions for the different substances are: 1. Detection of the identity of various pharmaceutical preparations (and if possible also the purity of the active substances, including testing for decomposition products); 2. Preparation of samples and implementation of TLC should involve the simplest procedures possible; 3. Only precoated plates with as few as possible common stationary phases from different manufacturers should be used; 4. The mobile phase systems should be as simple and non-toxic as possible and cause minimum pollution of the environment; 5. Special reference substances should not be necessary.

J. Planar Chromatogr. 11, 132-136 (1998). HPTLC of fourteen 1,4-benzodiazepines (diazepam, bromazepam, dipotassium chlorazepate, chlordiazepoxide, clonazepam, flurazepam flunitrazepam, nitrazepam, medazepam, lormetazepam, oxazepam, prazepam, temazepam, tofisopam; clobazam, midazolam, triazolam, alprazolam, clotiazepam) on silica gel with chloroform - acetone 4:1and benzene. After thermal treatment the Bratton - Marshall diazotization reaction can be used for the detection of benzodiazepines (BZ) and benzophenones when the substituent is a secondary amino group. Thermal treatment alone also gives color reactions with some BZ, and in combination with Bratton-Marshall reagent and the Rf values of the drugs serves as a specific method of identification of various BZ.

J. Planar Chromatogr. 12, 161-164 (1999). HPTLC of isosorbide mononitrate on silica gel with chloroform - methanol - acetic acid 270:30: 1. Evaluation by densitometry in absorbance mode at 200 nm. The HPTLC method for determination of IS-5-MN in pharmaceuticals has been fully validated and applied successfully for process-parameter assessment and in-process monitoring of Monosan tablets. Terfenadine was used as the internal standard. Large sample throughput, small solvent consumption, and robustness in terms of in situ analyte stability and applied volumes are the main advantages of the HPTLC method. System suitability results indicate that the method could be used for impurity and stability testing of IS-5-MN when IS-2-MN and ISDN (isosorbide dinitrate) are considered as impurities.

J. Liq. Chrom. & Rel. Technol.19, 17-21 (1996). HPTLC of salicylic acid on silica gel with n-pentyl formate - chloroform - formic acid 2:7:1. Detection under UV 254 nm; quantitation by densitometry in the single-beam reflectance mode. Variation coefficients for the analyses was 3.9 and 5.6 %, respectively.

Part 1. Lipophilicity of 1-(1-arylimidazolin-2-yl)-3-arylureas and 1-aryl-2-imine-3-arylaminocarbonylimidazolidines. J. Planar Chromatogr. 13, 52-56 (2000). Determination of the lipophilicity of forty new derivatives of 1-aryl-2-aminoimidazolines (twenty 1-(1-arylimidazolin-2-yl)-3-arylureas and twenty 1-aryl-1-2-imine-3-arylaminocarbonyl-imidazolidines) by RP-TLC with methanol - acetic acid - water. Visualization under UV at 254 nm.