Indian J. Pharm. Sci. 69(3), 473 (2007). Dried leaves were Soxhlet extracted with methanol and concentrated. HPTLC of andrographolide in Andrographis paniculata on silica gel with chloroform - methanol 7:1 with chamber saturation for 15 min. Densitometric evaluation at 232 nm. The hRf value of andrographolide was 35, of neoandrographolide 15 and of andrographoside 3. The linearity range was 200 - 1000 ng/zone. Average andrographolide contents were 1.56 % in dried leaves sample.

59th Indian Pharmaceutical Congress C-42, 234, (2007). HPTLC of E-guggulsterone (a steroidal ketone present in oily resin of Commiphora mukul) and five marketed ayurvedic tablet formulations, on silica gel with toluene - propane-1-ol - glacial acetic acid 8:1:1. Densitometry at 254 nm. The hRf of E-guggulsterone was 61. Several marketed formulations were evaluated for E-guggulsterone, the UV spectra of the standard and that of the formulations were comparable in respect of E-guggulsterone. The TLC pattern showed several other zones corresponding to unknown phytochemicals. The method was suitable for quantitative evaluation of formulation in respect of E-guggulsterone in presence of other phyto chemicals.

J. Planar Chromatogr. 21, 107-112 (2008). Optimization and comparison of the acidic visualization methods most often used for steroids. OPLC of ethinyl estradiol, ’dienolether’ (3-methoxyestra-2,5(10)-dien-17b-ol), norethisterone, norethisterone acetate, norethisterone enanthate, nandrolone, and nandrolone decanoate on HPTLC silica gel with cyclohexanone - ethyl acetate - chloroform 1:1:1. Detection with sulfuric acid at three different concentrations, phosphomolybdic acid, and phosphoric acid with different heating temperatures for different times. Evaluation under UV 366 nm (sulfuric acid, phosphoric acid) and in white light (phosphomolybdic acid). It was found that derivatization at higher temperatures for shorter periods usually results in greater sensitivity, although heating for longer periods at lower temperatures leads to a more stable and robust result. Evaluation by videodensitometry.

Chromatographia 67 (7-8), 607-613 (2008). Quantitative estimation of the two major alkaloids strychnine and brucine in Strychnos nux vomica by TLC on silica gel with chloroform - ethyl acetate - diethyl amine 1:17:2. The hRf values for strychnine and brucine were 55 and 42 and selectivity regarding matrix was given. Recovery was between 93.1 and 99.8 % for strychnine and between 96.9 and 99.5 % for brucine. The limit of detection and quantification for strychnine was 2 and 8 ng, respectively, and for brucine 2 and 9 ng, respectively.

Ind. J. Pharm. Sci. 69 (6) 841 - 844 (2007). HPTLC of artesunate on silica gel with toluene - ethyl acetate - acetic acid 20:80:2. Detection by treatment with vanillin reagent (1 % vanillin in 5 % ethanolic sulphuric acid) leads to pink zones which are stable for more than a day. Quantitative determination by absorbance measurement at 520 nm. The hRf value for artesunate was 44. Linearity was between 100 and 600 ng per spot. Recovery (by standard addition method) was 98.9 - 99.9 % for tablets and injections.

J. Chromatogr. A 1209 (1-2), 230-237 (2008). TLC of purines (adenosine and its major metabolites, inosine, and hypoxanthine) in rat brain tissue preparations, on silica gel with a two-step gradient mobile phase consisting of (1) n-butanol – water – acetonitrile - 10% ammonia - acetic acid 10:4:8:2:1 and (2) n-butanol – chloroform – acetonitrile - 10 % ammonia - acetic acid 10:4:8:2:1. Quantitative determination by absorbance measurement at 258 nm (via peak area). Application of the method to estimate the endogenous purines in discrete regions of rat brain. Development of a novel protocol for tissue preparation using 0.1 M HCl and 0.15 M NaOH solutions in 60 % methanol, which provided well-resolved peaks and high recoveries.

using HPLC, HPTLC and densitometry. Phytochem. Anal. 19, 550-559 (2008). HPTLC of the leaves of Lawsonia inermis L., on silica gel with ethyl acetate – formic acid – water 82:9:9 followed by drying at 110 °C for 15 min. Detection by spraying with diphenylborinic acid aminoethylester 0.5 % in ethyl acetate, followed by drying and dipping into macrogol reagent (1 g polyethylene glycol 400 in 20 mL dichloromethane). Quantitative determination by absorbance measurement at 337 nm. Chemical fingerprint was used for quality evaluation of herbal products and detection of adulteration. Comparison with an HPLC method gave comparable results.

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.