J. Planar Chromatogr. 23, 201-207 (2010). TLC and HPTLC of 17 5,5-disubstituted hydantoins on silica gel with ethyl acetate - toluene (with 30-60 % ethyl acetate) and acetonitrile - toluene (with 30-50 % acetonitrile) and on RP18 with methanol - water (with 56-80 % methanol) and acetonitrile - water (with 30-60 % acetonitrile) at room temperature without chamber saturation. Detection under UV 254 nm. The effect of the structures of the derivatives on their retention in both normal and reversed-phase modes was investigated by use of QSRR and molecular descriptors. Cross-validation indicated the best models are reliable QSRR models.

J. Liq. Chromatogr. Relat. Technol. 33, 825-836 (2010). NP-TLC of ibuprofen standard and in tablet extracts on silica gel (prewashed with methanol) with n-hexane - ethyl acetate - acetic acid 150:50:7 and RP-TLC on RP18 with methanol - water 9:1 in a saturated twin-trough chamber. Quantitaitve determination by absorbance measurement at 200 and 224 nm for NP-TLC and RP-TLC analysis, respectively. The hRf values were 61 and 67. Linearity was between 2.50-12.50 and 2.50-12.50 µg/spot, the correlation coefficient (r) was 0.998 and 0.994. LOD was 0.60 and 1.00 µg/spot, and LOQ 12.50 and 12.50 µg/spot. Recovery was 98.2 % and 96.1 %, with a standard deviation of 1.21 and 1.45, and RSD 1.28 and 1.81 for NP-TLC and RP-TLC, respectively.

Analytical Methods 2, 275-281 (2010). HPTLC on silica gel with toluene - methanol 9:1. The hRf value was 75. Densitometric evaluation at 372 nm. The method was linear in the range of 100-600 ng/band. The recovery was 99.2-100.4 %. The method was suitable for microemulsion based formulations without any interference from excipients.

J. Planar Chromatogr. 24, 331-336 (2011). HPTLC of pioglitazone (PIO), metformin (MET), and glimepiride (GLI) in pharmaceutical preparations on silica gel, prewashed with methanol, with acetonitrile - methanol - propanol - ammonium acetate solution 7:2:1:1 in a twin trough chamber saturated for 10 min. Quantitative determination by densitometry at 240 nm. The hRf value was 83, 21, and 89 for PIO, MET, and GLI, respectively. Linearity was in the concentration range of 300-1200 ng/band, 10-40 µg/band and 40-160 ng/band with correlation coefficients of 0.995, 0.996, and 0.998 for PIO, MET, and GLI, respectively. The LOD and LOQ was 57 and 171 ng for PIO, 6 µg and 18 µg for MET, and 12 and 36 ng for GLI. The %RSD for method and intermediate precision was below 2 %. The mean recovery (n = 5) was 98.2-99.5 % for PIO, 98.6-99.3 % for MET, and 98.7-99.7 % for GLI with %RSD between 0.4 and 1.3 %.

J. Planar Chromatogr. 24, 40-43 (2011). TLC of fluoxetine and citalopram on RP-18 with methanol - 0.05 M phosphate buffer (pH 5) - triethylamine 68:27:5 after chamber saturation for 15 min. Detection under UV light at 254 nm. Quantitative determination by densitometry in absorbance mode at 230 nm. Linearity was between 500 and 5000 ng/zone. Recovery was in the range of 100.8-101.1 % for fluoxetine and 99.7-100.9 % for citalopram. Corresponding %RSD values were less than 1.6 % for fluoxetine and 0.8 % for citalopram.

J. Liq. Chromatogr. Relat. Technol. 35, 484-498 (2012). HPTLC of vitamin K homologues including phylloquinone (1), menaquinone-4 (2), and menaquinone-7 (3) on silica gel with methanol - ethanol - isopropanol - water 15:1:1:3. Quantitative determination by absorbance measurement at 254 nm. The hRf values of compounds (1) to (3) were 56, 43 and 23, respectively. Linearity was in the range of 1-200 ng/band. Limits of detection and quantification were in the range of 0.2-0.9 and 0.7-2.5 ng/band, respectively. The intermediate/inter-day/intra-day precisions for (1) to (3) were in the range of 0.5-1.3 % (n=5). Recoveries were ranged from 95.3 to 100.8 %.

J. Planar Chromatogr. 25, 72-76 (2012). HPTLC of mirtazapine on silica gel with methanol - chloroform 9:1. Quantitative determination by absorbance measurement at 294 nm. The hRf of mirtazapine was 56. Linearity was in the range of 400-2000 ng/band. The intermediate/interday/intra-day precision was below 2 %.

J. Liq. Chromatogr. Relat. Technol. 36, 700-716 (2013). HPTLC of sertraline in bulk and formulation on silica gel with toulene - ethyl acetate 1:5+1 drop ammonia. Quantitative determination by absorbance measurement at 273 nm. The hRf value of sertraline was 70. Linearity was in the range of 25-2000 ng/zone. LOD and LOQ were 15.3 and 46.8 ng/zone. Intermediate precision was below 0.83 %. Recovery range was in the range of 99.6-100.3 %. The hRf values of acid and base-induced degradation products were 40, 52, 90 and 25.