J. Planar Chromatogr. 9, 197-198 (1996). TLC of sorbic acid, p-hydroxybenzoic acid, parabens, carbamazepine, methylparaben, propylparaben on silica with e.g. toluene - isopropanol - diethylamine 10:10:1 in the first direction and after impregnation of the plate with paraffin in n-hexane resp. with methanol - water - acetic acid 350:150:1, saturated with liquid paraffin, in the second direction. Detection under UV. The proposed approach has the advantage of enabling determination of p-hydroxybenzoic acid in the presence of other acidic compounds.

J. Planar Chromatogr. 9, 282-285 (1996). TLC of dextromethorphan hydrobromide and doxylamine succinate on silica with methanol - 25% NH3 14:1. Quantification by densitometry at 223 nm. RSD for dextromethorphan hydrobromide 1.51%, for doxylamine succinate 1.81%. Detection limit for dextromethorphan hydromide 0.13 mg/spot, for doxylamine succinate 1.05 mg/spot. Simple quantitative procedure for routine analysis.

Proc. 9th Internat. Symp. Instr. Chromatogr., Interlaken, April 9.-11., 231-237 (1997). HPTLC of granisetron (2-methyl-N-(endo-9-methyl-9-azabicyclo[3,3,1]non-9-yl)-2H-indazole-3-carboxamide hydrochloride) and its impurities on silica with ethyl acetate - 2-propanol - NH3 110:60:13. Quantification by densitometry at 303 nm. Linearity, selectivity, reproducibility, percentage recovery and detection limits of granisetron from dosage forms have been calculated. The method provides reliable results when applied to the analysis of raw materials and dosage forms. Fast, accurate and simple method.

J. Planar Chromatogr. 11, 254-257 (1998). TLC of salbutamol sulfate and bromhexine hydrochloride on silica gel with methanol - chloroform - triethylamine 110:90:1. Densitometry at 276 nm. Calibration curves were linear in the concentration range 20 - 580 ng/µl for both compounds. Recoveries were 98.84%; 99.0% and 99.62%; 99.63%, respectively. Simple, rapid and precise quantitative TLC method.

J. AOAC Int. 82, 31-37 (1999). Examination of the retention behavior of 10 dihydroxythiobenzanilides for acquisition of log k' data. With water-acetone mixtures as the mobile phases, the concentration range for which the correlation between log k' and acetone concentration is linear was established for each stationary phase and used to determine hydrophobicity parameters log k'w by linear extrapolation. TLC on RP-8 and RP-18 in a sandwich chamber with chamber saturation with organic solvent vapor. Water-acetone was applied as mobile phase, with the concentration of acetone in the range 0.3-1.0v/v at increments of 0.05 v/v. Detection by densitometry at 325 nm.

J. Liq. Chrom. & Rel. Technol. 22, 153-159 (1999). HPTLC of diphenhydramine hydrochloride on silica gel (after pre-cleaning of the plate by development to the top with dichloromethane - methanol 1:1) with ethyl acetate - methanol - NH3 17:2:1. Densitometry at 260 nm.

(Spanish). Bol. Soc. Chil. Quim. 44, 479-485 (1999). HPTLC validation of metamizol-Na on silica gel with ethyl acetate - methanol - NH3 (75:24:1) to 50 mm. Quantitation by densitometry at 273 nm by linear regression (50-250 ng). Limit of detection is 10,9 ng and limit of quantification 16,1 ng. CV is 2,45%, recovery is 102,48% (225 ng), 98,78% (250 ng) and 100,69% (275 ng). The HPTLC method is precise, exact, proportional, linear and sensitive. Results do not differ statistically from the Official Method described in the German Pharmacopoeia.

J. Planar Chromatogr. 13, 420-425 (2000). HPTLC of 18 2,4-dihydroxythiobenzanilides on RP-18 with mixtures of water with organic modifier (acetone or methanol) at concentrations from 0.4 to 0.75 at intervals of 0.5. Detection by densitometry at 325 nm. Determination of physicochemical parameters (retention factors, log kw, and hydrophobicity, A12) describing the structural properties and phase affinity of 2,4-dihydroxythiobenzanilides. The parameters obtained were further used to estimate the hydrophobic character and biological activity of the compounds examined.