Abstract No. F-365, 61st IPC (2009). HPTLC of rivastigmine hydrogen tartrate on silica gel with methanol - 25 % ammonia - acetic acid 200:7:2. The hRf value was 54. Quantitative determination by absorbance measurement at 215 nm. The method was linear in the range of 1-10 µg/band.

J. Planar Chromatogr. 23, 208-211 (2010). HPTLC of prednisolone (and hydrocortisone as impurity) on silica gel (prewashed with methanol) with chloroform - methanol 19:1 in a twin-trough chamber previously saturated for 30 min. Quantitative determination by scanning densitometry at 250 nm. Linearity was in the range of 2-10 µg/band (r = 0.9967, calculated via peak area). LOD and LOQ was 200 and 600 ng/spot, respectively. Recovery was 100.0 % for prednisolone. Repeatability was 0.74 % and the inter-day (n = 6) and intra-day (n = 12) precision was 2.6 and 2. 7 %, respectively.

J. Chromatogr. Sci. 48(8), 685-689 (2010). TLC combined with HPLC for detection of the intermediates and the end-product from the synthesis process of vinorelbine. Specific TLC separation of vinblastine sulfate, anhydrovinblastine, and vinorelbine on silica gel with petroleum ether - chloroform – acetone - diethyl amine 47:24:4:5. Quantitative evaluation with HPLC.

J. Pharm. Biomed. Anal. 53, 911-918 (2010). Comparative study on several approaches of TLC lipophilicity determination with the goal of standardization: single TLC runs, extrapolation of retention, principal component analysis of a retention matrix, PARAFAC on a three-way array and a PLS regression. All techniques were applied to 35 simple model solutes (e.g. benzoic acid, caffeine, benzocaine, isoniazide) using nine concentrations of six modifiers (acetonitrile, acetone, dioxane, propan-2-ol, methanol and tetrahydrofurane). Methanol and dioxane were most suitable as modifiers, while acetonitrile provided no suitable correlation of retention with lipophilicity. The approach of single TLC runs provided surprisingly good results. The chemometric processing methods (PCA, PARAFAC and PLS) did not show any advantage compared to classical methods. There is a need to use robust regression and correlation measures due to presence of significant outliers.

J. Planar Chromatogr. 24, 227-231 (2011). TLC of diethylamino hydroxybenzoyl hexyl benzoate (DHHB) and octyl methoxycinnamate (OMC) on silica gel with cyclohexane - diethyl ether - acetone 15:1:2 with chamber saturation for 20 min. Quantitative determination by densitometry in absorbance mode at 300 nm (for OMC) and 360 nm (for DHHB). Linearity was between 200 and 2000 ng/zone both for DHHB and OMC. LOD and LOQ was 50 and 472 ng/zone for DHHB and 50 and 488 ng/zone for OMC. The hRf value was 30 for DHHB and 47 for OMC. Recovery of DHHB was between 97.8-101.9 % and of OMC between 98.8-102.7 %

J. AOAC Int. 93, 783-786 (2010). HPTLC of etoricoxib (ETO) and thiocolchicoside (THIO) on silica gel (prewashed with methanol) with ethyl acetate - methanol 4:1 in a twin-trough chamber after preconditioning for 20 min. Quantitative determination by absorbance measurement at 290 nm. The calibration curve was linear over a range of 50-250 and 100-500 ng/band with correlation coefficients of 0.9948 and 0.9958 for ETO and THIO, respectively. LOD and LOQ were 11 and 33 ng/band for ETO and 25 and 76 ng/band for THIO. %RSD values were found to be 0.5 and 0.8 % for ETO and THIO for intra-day variations, while inter-day variations were 1.2 and 1.0 %, respectively. The recovery for ETO was between 100.2-101.1 % and for THIO 98.7-100.4 %.

J. Liq. Chromatogr. Relat. Technol. 35, 1459-1480 (2012). HPTLC of itraconazole on silica gel with toluene - ethyl acetate 1:5 + 1 drop ammonia. Quantitative determination by absorbance measurement at 266 nm. The hRf value of itraconazole was 77 and selectivity regarding matrix was given. Linearity was in the range of 50-2000 ng/zone. The intra-day and inter-day accuracy were in the range of 81.9-97.8 and 89.2-97.1 %, respectively. The limits of detection and quantification were 14 and 43 ng/zone, respectively. Recovery (by standard addition) was between 99.6 and 100.2 %.

J. Liq. Chromatogr. Relat. Technol. 36, 1528-1539 (2013). HPTLC of mebeverine hydrochloride (1), metronidazole benzoate (2), diloxanide furoate (3) and metronidazole (4) in pharmaceutical suspensions on silica gel with hexane - acetone - triethylamine 35:15:3. Quantitative determination by absorbance measurement at 254 nm. The hRf values of compounds (1) to (4) were 10, 34, 49 and 64, respectively. Linearity was 0.4-2.4 µg/zone for (1), 0.3-2.0 µg/zone for (2) and 0.4-2.4 µg/zone for both (3) and (4). Intermediate precision was below 1.2 %. Recovery (by standard addition) was 99.9-100.1 % for compounds (1) to (4). Comparable results were obtained when compared with reported RP-HPLC methods.