J. Planar Chromatogr. 22, 425-428 (2009). HPTLC of olmesartan medoxomil and hyrochlorothiazide on silica gel, prewashed with methanol, with chloroform - methanol - toluene 6:4:5 in a twin trough chamber saturated for 15 min. Quantitative determination by absorbance measurement at 258 nm.

J. Planar Chromatogr. 22, 405-410 (2009). TLC of hydrochlorothiazide, triamterene, furosemide, and spironolactone on silica gel with hexane - ethyl acetate - methanol - water - acetic acid 42:40:15:2:1 with chamber saturation. Quantitative determination by absorbance measurement at 264 nm. The limit of detection for the different compounds was between 22 and 150 ng/band, and the limit of quantification was between 68 and 450 ng/band.

Abstract No. F-245, 61st IPC (2009). HPTLC of atorvastatin (AT) calcium, ramipril (RA) and aspirin (AS) on silica gel with benzene - ethyl acetate - toluene - methanol - acetic acid 40:45:10:5:1. Quantitative determination by absorbance measurement at 220 nm. The hRf values were 45, 28 and 72 for AT, RA and AS, respectively. The linearity ranges were 0.5-2.5 µg/band (r2=0.998) for AT, 0.5-2.5 µg/band (r2=0.9978) for RA and 0.75-3.75 µg/band (r2=0.9946) for AS with mean recoveries of 100.3, 99.1 and 98.9 for AT, RA and AS, respectively.

Abstract No. F-252, 61st IPC (2009). HPTLC of tenofovir on silica gel with n-butanol - acetic acid - water 4:1:1. The hRf value was 58. Quantitative determination by absorbance measurement at 260 nm. Linearity was in the range of 120-600 ng/band. The compound was subjected to different stress conditions (acid, alkali, oxidation, photodegradation and thermal) and degradations products were well resolved from the main component.

Abstract No. F-247, 62st IPC (2009). HPTLC of nebivolol HCl and S-amlodipine besylate on silica gel (prewashed with methanol) with chloroform - toluene - methanol - acetic acid 50:20:1. The hRf value was 33 and 48 for S-amlodipine and nebivolol, respectively. Quantitative determination by absorbance measurement at 271 nm. The method was linear in the range of 500-2500 ng/band for nebivolol and 250-1280 ng/band for S-amlodipine, respectively.

J. Planar Chromatogr. 23, 84-86 (2010). TLC of 18 drugs (6 antibiotics [benzyl-penicillin procaine, benzyl-penicillin potassium, penicillic acid, tetracycline hydrochloride, oxytetracyline hydrochloride, chlortetracycline hydrochloride], 2 analgesics [aminophenazone, salicylamide], 2 anaesthetics [phenazone, procaine hydrochloride], and one each of anti-rheumatic [penicillamine], anti-inflammatory [metamizole sodium], antitussive [codeine phosphate], broncholytic [aminophylline], spasmolytic [papaverine hydrochloride], hypnotic [phenobarbital], sympathomimetic [ephedrine hydrochloride] and vitamin [ascorbic acid] drugs) on silica gel with butanol - anhydrous acetic acid - water 3:1:1. Detection by spraying with 10 mL each of a solution of (A) 0.25 g titanum dioxide in 0.1 mol/L potassium permanganate, (B) 0.25 g titanium dioxide in 1.0 mol/L potassium iodide, (C) 0.25 g titanium dioxide in 1.0 mol/L potassium bromide, which was the best (most sensitive) one, and (D) 0.25 g titanium dioxide in 1.0 mol/L potassium chloride. After spraying with reagents C and D, plates were illuminated for 10 min, sprayed with 0.1 mol/L silver nitrate solution and illuminated again for 3 min. In all experiments the TLC plates were illuminated by use of UV lamps with the radiation at 366 nm. LODs for most of the drugs studied were in the range 0.2-0.5 µg/spot.

J. Planar Chromatogr. 23, 212-218 (2010). TLC of bupropion on silica gel with ethanol - chloroform - glacial acetic acid 30:10:1. The hRf value was 56. Quantitative determination by densitometry at 254 nm. Linearity was in the range 200-1000 ng/band (via peak area). The limits of detection and quantitation were 11 and 35 ng per band, respectively. The intra-day repeatability of the method was around 1-2 % RSD. Recovery was between 102.1 and 104.6 % and between 97.2 and 102.2 % for quality-control standards and for bupropion hydrochloride, respectively.

62nd Indian Pharmaceutical Congress Abstract No. F-382 (2010). The partition coefficient (logP) of a drug in benzene – water is an important parameter to determine the absorbance of the drug in body, thus influencing its therapeutic response. A NP-TLC method for the determination and calculation of log P values is proposed. By this method differential values like Rfb/w, LogRfb/logRfw were calculated, which were very close to values reported in literature. LogP values of different drugs were 0.46 for paracetamol, 0.22 for atenolol, 5.11 for telmisertan, and 0.9 for nimesulide.