60th Indian Pharmaceutical Congress PA-216 (2008). HPTLC of isomers of bupropion HCl on silica gel with quinine sulphate - methanol - water 13:20:12 (quinine sulphate served as a chiral selector). Evaluation under UV 366 nm. Linearity was in the range of 10-100 µg/spot for d(+)- and l(-)-isomers of bupropion. The isomer ratio was 80 % d(+)-bupropion and 20 % l(-)-bupropion.

J. Planar Chromatogr. 22, 355-358 (2009). TLC of atorvastatin calcium and fenofibrate on silica gel, prewashed with methanol, with toluene - methanol - triethylamine 35:15:1 in a twin trough chamber saturated for 25 min at room temperature and relative humidity of 60 +/- 5 %. Quantitative determination by absorbance measurement at 258 nm. The limit of detection and quantification for atorvastatin calcium was 25 and 77 ng/zone, respectively and for fenofibrate 292 and 886 ng/zone, respectively.

Abstract No. F-159 61st IPC (2009). HPTLC of telmisartan and amlodipine besylate on silica gel with tetrahydrofuran - dichloroethane - methanol - 25 % ammonia 30:10:5:2. Both compounds were well resolved with hRf values of 22 and 45 for telmisartan and amlodipine besylate respectively. Densitometric evaluation at 326 nm. The method was found to be linear in the range of 1200-7200 ng/band for telmisartan and 400-1400 ng/band for amlodipine besylate.

J. Liq. Chromatogr. Relat. Technol. 33, 179-190 (2010). TLC of salicylic acid and its derivatives, namely acetylsalicylic acid, salicylanilide, salicylaldehyde, salicylamide, salicylhydroxamic acid, methyl salicylate, phenyl salicylate, 3,5-dinitrosalicylic acid, 2,5-dihydroxysalicylic acid, 3-aminosalicylic acid, 4-aminosalicylic acid, and 5-aminosalicylic acid, on RP8, RP18 and HPTLC on RP18 and cyano phase with methanol - water; the content of methanol in mobile phase was gradually varied by 5 % from 20-100 %. Development in a chamber saturated for 15 min. Quantitative determination by scanning densitometry in absorption mode at the respective absorption maximum. The hRf values were recalculated on the RM values. The chromatograms were repeated in triplicate and mean hRf values were calculated. The results indicate that the chromatographic parameter of lipophilicity determined on RP8 and cyano phase may be used as a measure of lipophilicity of the investigated salicylic acid and its derivatives.

J. Serb. Chem. Soc. 74(6), 677-688 (2009). An NP-TLC method has been reported to study the lipophilicity of 5 ACE inhibitors (lisinopril, quinapril, fosinopril, enalapril, cilazapril and their metabolites). TLC on silica gel with several non-aqueous mono and binary solvent systems. Binary mobile phases demonstrated a decrease in hRf values of all 5 ACE inhibitors, i.e. increased retention with increased amounts of the less polar component in the mobile phase. Metabolites usually exhibited stronger retention, i.e. lower hRf values than the corresponding ACE inhibitor. This is probably due to a different interaction with silica gel because of two carboxylic groups in the structure of the metabolites, whereas ACE inhibitors contain only one carboxyclic group. Results obtained on NP-TLC were compared with those by RP-TLC and no significant difference was found regarding lipophilicity.

J. AOAC Int. 93, 1836-1843 (2010). HPTLC of 1) lamivudine-zidovudine on silica gel with ethyl acetate - toluene - methanol 12:5:3, quantitative determination by absorbance measurement at 289 nm; of 2) metronidazole with ethyl acetate - ammonia 50:1, quantitative determination by absorbance measurement at 313 nm; of 3) neviparine with ethyl acetate - toluene 3:1, quantitative determination by absorbance measurement at 289 nm; and of 4) quinine with ethyl acetate - toluene - acetone 22:3:5, quantitative determination by absorbance measurement at 327 nm in a twin-trough chamber lined with wetted filter paper and saturated for 20 min. The average repeatability (within-laboratory) was 1.9 %, with 73 % less than 2 % and 97 % at 2.6 % or less. The average reproducibility (among-laboratory) was 2.7 %. Mean hRf values for lamivudine, metronidazole, neviparine, quinine, and zidovudine were 19, 28, 34, 33, 57.

J. AOAC Int. 93, 778-782 (2010). TLC of mirtazapine and mianserine in tablets on silica gel with n-hexane - isopropanol - 25 % ammonia 70:25:59. Quantitative determination by absorbance measurement at 280 nm. Calibration curves were linear (r2 > 0.9970) with respect to peak area in the concentration range of 500-2500 and 500-5000 ng/zone for mirtazepin anf mianserine, respectively. The LOD was 20 and 35 ng/zone for mirtazepin and mianserine, respectively. LOQ was 50 and 85 ng/zone for mirtazepin and mianserine, respectively. The instrumental precision (%RSD; n = 6) was 0.3 and 0.2 %, the repeatability of standards (%RSD; n = 6) was 0.4 and 0.5 % for mirtazepin and mianserine, respectively. The recovery values were found to be 101.2 % for mirtazepin and 99.8 % for mianserine.

J. Planar Chromatogr. 24, 428-434 (2011). HPTLC of 6-benzyl-, 6-methyl-, and 6-propyl-2-thiouracil and spiked urine samples on silica gel with methanol in a horizontal chamber saturated for 15 min at ambient temperature. Detection by spraying with a freshly prepared mixture of 4 % sodium azide and 1 % starch solution adjusted to pH 5.5, followed by exposure to iodine vapor for 5 s. Quantitative evaluation by use of an office scanner at 300 dpi resolution. The images were inverted and stored in the form of 24-bit-true color images, which were analysed by TLSee software. The determination range was 7-16 pmol/zone, 80-160 nmol/mL urine, or 133-266 nmol/mL serum. The recovery was between 93-106 %. The LOQ was 4 pmol/zone for the studied thiouracils in three investigated matrices.