Part I. Nicotinic acid and its amides. J. Liq. Chromatogr. Relat. Technol. 30, 2317-2327 (2007). TLC and HPTLC of nicotinic acid, nicotinamide, N-methylnicotinamide, and N,N-diethylnicotinamide on RP-18 with methanol - water 3:7, and dioxane - water 1:4 and 1:9. The best separation was achieved on alumina with acetone - n-hexane 1:1. Detection under UV light at 254 nm. Quantitative determination by absorbance measurement at 254 nm.

Food Chemistry 113, 640-644 (2009). HPTLC of curcumin (1), demethoxycurcumin (2), and bisdemethoxycurcumin (3) from the rhizomes of Curcuma longa on silica gel with chloroform – methanol 24:1. Quantitative determination by absorbance measurement at 425 nm. The hRf values of (1), (2), and (3) were 66, 48, and 30, respectively. Selectivity regarding matrix was given. Recovery was 98.7 % for (1), 96.3 % for (2), and 97.2 % for (3). The limit of detection for (1), (2), and (3) was 0.1 µg/spot. The linear regression equation was y=4447.26 + 61.993X for (1), y=1089.881 + 70.003X for (2), and y=2611.84 + 51.565X for (3).

60th Indian Pharmaceutical Congress PA-204, (2008). HPTLC of carvedilol on silica gel with methanol - ethyl acetate 13:7. The hRF was 49. Quantitative determination by absorbance measurement at 242 nm. Linearity was between 200-1000 ng/spot. The recovery was 98-102 %. The method was suitable for routine quality control of the drug in formulation.

J. Pharm. Res. 7(2), 126-128 (2008). HPTLC on silica gel with acetone - chloroform - ethyl acetate - methanol 6:6:6:1. Quantitative determination by absorbance measurement at 280 nm. The hRf value for telmisartan was 27 and for hydrochlorothiazide 45. The regression curve shows good linear relationship in the concentration range of 25.5 - 128.0 µg for hydrochlorothiazide and 81.6 - 408.0 µg for telmisartan. The content uniformity test was carried out as per the USP specification of the content uniformity test. The percent drug estimated from the marketed formulations were found to be in the range 99.3 and 100.5 for both drugs. The percent recoveries of drug carried out by the standard addition method was found to be 100.3 and 99.4 for hydrochlorothiazide and telmisartan respectively. The proposed method was found suitable for routine quality control and content uniformity tests.

J. Liq. Chromatogr. Relat. Technol. 30, 2369-2383 (2007). TLC of 2-arylpropionic acids, namely ibuprofen and naproxen, on silica gel and silica gel impregnated with a 0.03 mol/L solution of L-arginine in methanol by dipping for 2 s, with ethanol and ethanol containing several drops of acetic acid. Quantitative determination by absorbance measurement at 254 nm. It was demonstrated that the crystalline chirality of the silica gel adsorbent is most probably responsible for the horizontal enantioseparation, whereas the molecular chirality of L-arginine deposited on the silica gel layer is responsible for the vertical enantioseparation.

Ind. J. Pharm. Sci. 69 (5), 689 - 686 (2007). A simple, fast precise and accurate HPTLC method has been developed for the simultaneous estimation of lansoprazole and domperidone in tablet formulations. This method allows the determination of 100-500 ng/spot of lansoprazole and 100-500 ng/spot of domperidone. HPTLC on silica gel with n-butanol - acetic acid - water 36:12:1:2. Quantitative determination by absorbance measurement at 288 nm. The hRf value of lansoprazole was 78 and of domperidone 21. The limit of detection and quantification for lansoprazole was 10 ng/spot and 40 ng/spot, and for domperidone 30 ng/spot and 65 ng/spot, respectivey. The method was suitable for routine quality control.

The effect of a complex biological matrix on quantitative performance. J. Planar Chromatogr. 22, 9-14 (2009). HPTLC-OPLC of fructose, glucose, galactose, sucrose, lactose, 1-kestose, raffinose, nystose, and fructosil-nystose on silica gel with acetonitrile - water 17:3. After development and drying, the separated bands were derivatized by a thermal in-situ reaction on a hot plate. The plates were immersed in lead(IV) acetate-dichlorofluorescein reagent for 9 s and heated at 105 °C for 3 min. Quantitative determination by fluorescence measurement at 313 nm.

Ind. J. Pharm. Sci. 70(5), 644-647 (2008). HPTLC of meloxicam on silica gel with ethyl acetate - cyclohexane - glacial acetic acid 325:175:1 with chamber saturation for 45 min. Quantitative determination by absorbance measurement at 353 nm. The method was linear in the range of 100-500 ng/zone, recovery was 100.3 %. The method was evaluated for stability (acid, base, thermal, oxidative, photodegradation) and degradation products were well separated from the main drug.