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  • Author or Editor: Ramesh Sane x
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Among the complex mixture of biologically active compounds in the leaves of Alstonia scholaris , a plant used in traditional medicine, ursolic acid, a constituent of the leaves, has been used as an analytical marker indicative of the quality of the plant. A sensitive thin-layer chromatographic method has been developed for determination of ursolic acid in the leaves of Alstonia scholaris . Chromatographic separation was performed on silica gel HPTLC plates with toluene-ethyl acetate-triethylamine-methanol, 7 + 2 + 1 + 1 ( v/v ), as mobile phase. The plates were scanned densitometrically at λ = 366 nm. The method was validated for precision, repeatability, and accuracy. Intra-day and inter-day RSD were 0.43% and 1.54%, respectively. Instrumental precision and repeatability of the method were found to be 0.54 and 1.20 (% CV), respectively. The accuracy was checked by studying recovery at three levels; average recovery was 100.26%. The method proposed for quantitative monitoring of ursolic acid in Alstonia scholaris is rapid, simple, and accurate and can be used for routine quality testing.

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Aerva lanata collected during summer, monsoon and winter were subjected to similar extraction conditions as well as sample application conditions on precoated silica 60F254 TLC plates. The plates were developed in ethyl acetate-toluene (7:3 v/v) in order to study the seasonal variation in HPTLC fingerprints. A similar procedure was also followed for the plant samples collected from three different states of India, in order to study the geographical variation. p-Hydroxybenzoic acid, used as reference standard for comparison with each sample, was observed in samples collected in all three seasons but in different concentrations. The compound was also observed in samples collected from Gujarat and Maharashtra, but was found to be absent in the sample from Kerala. The sample from Kerala showed a different compound at R F 0.74, having a λ max of 280 nm. This compound exhibited a spectrum very different from that of p-hydroxybenzoic acid having a λ max of 252 nm, which separates out at R F 0.73 on the plate. The proposed method was validated according to ICH guidelines in terms of linearity, accuracy and specificity, intra-day and inter-day precision, repeatability of measurement of peak area, repeatability of sample application and specificity. The calibration graph was found to be linear over a range of concentration of 25.0–175.0 ng, with a regression coefficient of 0.9986. Determination of accuracy by standard addition method at three different concentration levels returned a mean recovery value of 97.24 ± 7.36. Intra-day and inter-day precision values were found to be less than 2%. The relative standard deviations (RSDs) of repeatability of sample application and measurement of area were found to be 1.24% and 0.93%, respectively.

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Eugenol is used as a flavor in the food industry, has a variety of biological activity, and can serve as a biomarker. Because eugenol is present in the leaves of Cinnamomum tamala Nees and Eberm., which are used as a spice, a sensitive and reliable quantitative high-performance thin-layer chromatographic method has been established for quantification of the compound in the leaves of the plant. A methanol extract of the powder of dried leaves of Cinnamomum tamala Nees and Eberm. was applied to silica gel 60 F 254 TLC plates and these were developed with toluene-ethyl acetate-formic acid, 90 + 10 + 01 ( v/v ), as mobile phase. Detection and quantitation was performed by densitometry at λ = 280 nm. The accuracy of the method was checked by conducting recovery studies for two different levels of eugenol; the average recovery was found to be 98.39%. The average eugenol content, as estimated by use of the proposed method, was 5.405 mg g −1 . The HPTLC method proposed for the quantitative monitoring of eugenol in Cinnamomum tamala leaf powder is rapid, simple, and precise.

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A high-performance thin layer chromatographic method has been developed for the determination of rosiglitazone in pharmaceutical preparations. This method uses silica gel 60F 254 as the stationary phase, ethyl acetate-toluene-methanol, 45 + 55 + 1 ( v/v ) as mobile phase. Detection was performed at 242 nm and pioglitazone hydrochloride was used as internal standard. The response was found to be linearly dependent on amount of rosiglitazone between 100 and 1200 ng. The method was validated to determine its accuracy and precision. System-suitability tests were conducted to verify that the resolution and reproducibility of the system were adequate for the analysis. The determination of rosiglitazone in tablets is described.

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A sensitive and reliable high-performance thin layer chromatographic method has been developed for quantitation of camptothecin in the dry stem powder of Nothapodytes foetida (Wight) Sleumer. A methanolic extract of the dry powder was chromatographed on silica gel 60F 254 plates with toluene-acetonitrile-glacial acetic acid, 6.5 + 3.5 + 0.1 ( v / v ), as mobile phase. Detection and quantitation were performed by densitometric scanning, in fluorescence mode at λ = 370 nm, by use of a mercury lamp. The accuracy of the method was checked by determination of recovery, using the standard-addition method. Recovery was 99.49%. The average camptothecin content of the powder was 0.059%. The method is rapid, simple, and precise.

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A normal-phase high-performance thin-layer chromatographic (HPTLC) method has been established for quantitative estimation of itopride hydrochloride, a gastroprokinetic agent, in its pharmaceutical formulation and in the bulk drug substance. Analysis was performed on silica gel 60F 254 TLC plates with methanol-ethyl acetate-toluene-triethylamine, 1.0 + 2.5 + 6.0 + 0.5 ( v/v ), as mobile phase. Detection and quantitation were performed densitometrically at 1 = 230 nm. Diltiazem hydrochloride was used as the internal standard. Response to itopride hydrochloride was found to be linear in the concentration range 50.00 to 2000.00 μg mL −1 . The method was validated for accuracy and precision. Accuracy was checked by conducting recovery studies; the average recovery was found to be 99.27%. The method is simple, rapid, and precise and can be used for routine quality control.

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A sensitive, simple, and accurate reversed-phase high-performance thin-layer chromatographic method has been established for determination of protodioscin in fruit powder from Tribulus terrestris L. A methanol extract of the fruit powder was used for experimental work. Separation was performed on RP-18F 254s HPTLC plates with 0.1 m KH 2 PO 4 -acetonitrile-methanol-triethylamine, 5 + 4 + 1 + 0.1 ( v/v ), as mobile phase. After development, plates were treated with 0.1 m H 2 SO 4 and detection and quantification were performed by densitometry at λ = 366 nm. Detection and quantitation limits were 0.03 μg and 0.05 μg, respectively. Response was a linearly dependent on amount of protodioscin in the range 0.05 to 1.00 μg. The validated RP-HPTLC method can be used for a routine quality-control analysis of Tribulus terrestris L. fruit powder and quantitative determination of protodioscin.

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This paper describes a high-performance thin-layer chromatographic method developed for determination of doxazosin in its pharmaceutical formulation. The analysis was performed on aluminum foil-backed silica gel 60 F 254 HPTLC plates with ethyl acetate-methanol, 9 + 1 (v/v) as mobile phase. Detection was performed at λ = 277 nm. Terazosin hydrochloride, a structurally similar molecule was used as internal standard. The developed method was subjected to statistical validation to determine its accuracy and precision. The repeatability was also determined. System suitability tests were performed to verify that the resolution and reproducibility of the chromatography was adequate for the analysis to be done. The determination of doxazosin in tablets is described.

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A sensitive, simple, and reliable reversed-phase HPTLC method has been established for quantification of mimosine in Mimosa pudica Linn. whole plant powder. The plant powder was first extracted with methanol. The residue was then extracted with water and the aqueous extract was used for quantification. Chromatography was performed on silica gel RP-18 F254s plates with ethyl acetate-glacial acetic acid-water, 6 + 1 + 1.7 ( v/v ), as mobile phase. Quantification was achieved by densitometric scanning at λ max = 282 nm in reflectance-absorbance mode. The response to mimosine was a linear function of concentration over the range 30 to 100 μg mL −1 in the extract. The amount of mimosine in M. pudica was found to be 20 mg g −1 whole plant powder. The method was validated for linearity, precision, accuracy, and robustness.

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