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.

60th Indian Pharmaceutical Congress PA-195, (2008). HPTLC of trandolapril on silica gel with toluene - ethyl acetate - methanol - formic acid 5:16:2:1. The hRf value of trandolapril was 51. Trandolapril was subjected to different stress conditions like acidic and alkaline hydrolysis, oxidation, dry heat, wet heat, neutral condition and photodegradation. The degradation products were well resolved from the pure drug. Quantitative determination by absorbance measurement at 220 nm. Linearity was between 300-1800 ng/spot. The method was suitable for routine analysis of the drug in bulk and pharmaceutical dosage form.

J. Pharm. Res. (7)4, 229-232 (2008). HPTLC of lumefantrine and artemether on silica gel with toluene - ethyl acetate - formic acid 60:60:7. Quantitative determination by absorbance measurement of lumefantrine at 267 nm and of artemether at 561 nm. The hRf value for lumefantrine was 54 and of artemether 89. Linearity was in the range of 1200-6000 ng/spot for lumefantrine and 200-1000 ng/spot for artemether. The method was successfully applied to the analysis of commercial formulations.

Food Chem. 114, 1413-1420 (2009). HPTLC of methanolic fractions of stingless bee honey samples and commercial samples from Apis mellifera (European honey bee) on silica gel with a five step development with two different mobile phases: ethyl acetate - formic acid - acetic acid - water 100:11:11:27 and toluene - ethyl acetate - acetic acid 10:9:1. Detection by fluorescence measurement at 400 nm and absorbance measurement at 240 nm, after fluorescence induction at 365 nm with a mercury vapor lamp. Detection of flavonoids by spraying with an aqueous solution of 4 % aluminium sulphate. Flavonoids and coumarins were identified by comparison with commercial standards.

J. Planar Chromatogr. 21, 361-366 (2008). OPLC of xanthine standards (caffeine, theophylline, theobromine) and green tea extract on silica gel (prewashed with 15 mL acetonitrile - water 17:3) with chloroform - trifluoroacetic acid - acetonitrile - methanol 760:40:67:133. Quantitative determination by absorbance measurement at 280 nm. Xanthine standards were used as model compounds to test the connected systems OPLC-UV and OPLC-DAD-ESI-MS. Sensitivity of OPLC-UV or OPLC-DAD was increased by hyphenation with ESI-MS coupled in series. After background subtraction the extracted ion chromatogram ( m / z = 181.1 Da) yielded well measurable peaks for theophylline and theobromine in tea leaf extract. Analysis time was 10 min only.

Anal. Chim. Acta, 572 (2), 237-242 (2006). Presentation of a stability-indicating method for simultaneous determination of the steroidal hormones levonorgestrel and ethinyloestradiol both in bulk drug and in low-dosage oral contraceptives by HPTLC on silica gel with hexane - chloroform - methanol 4:12:1. The hRf value of levonorgestrel was 65 and of ethinyloestradiol 43. The compounds were well separated from their degradation products. Quantitative determination by absorbance measurement at 225 nm. Linearity of levonorgestrel and ethinyloestradiol was 200–800 and 40–160 ng/spot, respectively.

J. Sep. Sci. 32, 1454-1458 (2009). HPTLC of carbamazepine in human serum on silica with ethyl acetate – toluene – methanol – glacial acetic acid 10:8:1:1. Detection by dipping in a solution of perchloric acid 60 % – ethanol – water 1:1:1, followed by heating at 120-150 °C for 5-10 min. Quantitative determination by fluorescence measurement at 366/>400 nm. The accuracy and precision did not exceed 3.2 % RSD at any level. The hRf value of carbamazepine was 55 and selectivity regarding matrix was given. Linearity was between 3 and 20 ng/µL. The intra-assay and inter-assay precision, expressed as the RSD, were in the range of 0.4 - 1.2 % (n = 3) and 2.2 - 3.2 % (n = 9), respectively. The limit of detection and quantification was 0.19 and 0.57 ng, respectively. Recovery (by standard addition) was between 99.0 and 102.0 %.