Quantitative high-performance thin-layer chromatography of nucleosides

A procedure was developed for express analysis of thymidine by high-performance thin-layer chromatography in the cultural liquid in the course of microbiological synthesis.     

Rapid assessment of beta-asarone content of Acorus calamus by micellar electrokinetic capillary chromatography

This report outlines a rapid, reproducible method for the determination of beta-asarone, a known carcinogen, using micellar electrokinetic capillary chromatography (MEKC)-UV-vis absorbance and a simple alcohol extraction. The MEKC method is based on a running buffer comprised of 100 mM sodium dodecyl sulfate (SDS), pH 10. The method is reproducible and provides baseline separation of alpha-asarone and beta-asarone. This protocol was used to determine the beta-asarone content of Acorus calamus rhizome of a diploid variety harvested from the wetlands of the United States and the triploid variety from India obtained commercially. The results indicate raw product that originated from India contained 4.4% w/w beta-asarone, while that from the United States contained 0.2% w/w beta-asarone. Neither sample contained detectable concentrations of alpha-asarone. This is the first report of the use of MEKC to determine asarone in a natural source.     

Quantitative determination of valienamine and validamine by thin-layer chromatography

A simple and valid thin-layer chromatographic method for the separation and quantitative determination of valienamine and validamine is described. The two compounds are separated using a Silica gel G plate as the stationary phase and a mixture of 1-PrOH-AcOH-H2O (4:1:1, v/v/v) as the mobile phase. The plate is developed for 1 h at 25 degrees C and dried by a hairdrier, then immersed in 0.1% ninhydrin aqueous solution and heated for 5 min at 121 degrees C. The reacted spots are scanned with a single wavelength at 420 nm in the measurement mode of absorption. The limits of detection of the two compounds are both 0.4 microg. The responses of the densitometry are highly correlated with the amounts of valienamine and validamine in the range of 0.4-2.8 pg. Moreover, the method shows good accuracy and high precision.     

Quantitative determination of celanide by high-performance liquid chromatography

Methods have been developed for the quantitative determination of celanide [lanatoside C] in substances, in solutions for injection, and in tablets by high-performance liquid chromatography, with the aid of which it is possible to determine small amounts of celanide (0.025 mg/ml) with adequate accuracy. The relative error of the determination does not exceed ±4.0%.All-Union Scientific-Research Institute of Physical Culture, Moscow. Translated from Khimiya Prirodnykh Soedinenii, No. 4, pp. 476–479, July–August, 1983.     

Quantitative determination of haloperidol in tablets by high performance thin-layer chromatography

A densitometric high performance thin-layer chromatography (HPTLC) method was developed and validated for the quantitative analysis of haloperidol in tablets. Chromatographic separation was achieved on precoated silica gel F 254 HPTLC plates using a mixture of acetone/chloroform/n-butanol/acetic acid glacial/water (5:10:10:2.5:2.5 v/v/v/v/v) as the mobile phase. Quantitative analysis was carried out at a wavelength of 254 nm. The method was linear in the 10-100 ng/microL range, with a determination coefficient of 0.999. The coefficients of variation for precision were not higher than 2.35%. The detection limit was 0.89 ng/microL, and the quantification limit was 2.71 ng/microL. The accuracy ranged from 97.76 to 100.33%, with a CV not higher than 4.50%. This method was successfully applied to quantify haloperidol in real pharmaceutical samples, including the comparison with HPLC measurements. The method was fast, specific, with a good precision and accuracy for the quantitative determination of haloperidol in tablets.     

Quantitative determination of miconzole in human serum by high-performance liquid chromatography

Summary A high-performance liqid chromatographic method is reported for the measurement of miconazole in systemic, fungal infectious patients. Pharmacokinetic data are presented for a single patient receiving miconazole therapy. Sample preparation involves protein precipitation by acetonitrile (1:1, vol/vol). Analyses are carried out on a reversed-phae chromatographic system using octadecylsilane stationary phase: a mobile phase consisting of 0.05 M acetate buffer (pH 7.4)acetonitrile (20:80, vol/vol) is used to elaute miconazole is quantified on the basis of ultraviolet absorption at 220 nm. The precision of the method ranged from 3.21% at 0.5 mg/L to 0.85% at 2.0 mg/L. The limit of quantification was established as 0.1 mg/L. Interference from other drugs that are co-adimistered such as amphotericin B, 5-fluorocytosine of ketoconazole and most other comonly encountered drugs was not observed.     

Quantitative determination of phospholipids in amniotic fluid by high-performance liquid chromatography

Summary A new quantitative analytical method for the determination of phospholipids in amniotic fluid by high performance liquid chromatography (HPLC) is described. In addition to the main compounds, phosphatidylcholine (lecithin) and sphingomyelin, the so-called minor phospholipids, phosphatidylglycerol, phosphatidylinositol and phosphatidylethanolamine can also be determined. Separation is achieved using a guard-column of Lichrosorb Si 60 and an analytical column of Lichrosorb DIOL. Acetonitrile/water is used as mobile phase at an elevated temperature. By determining the recovery rates, the within-run and the between-run precision, it was shown that sufficient accuracy and precision could be achieved for all the parameters examined. The method is highly sensitive, the detection limit for sphingomyelin is 0.2 μg and 0.1 μg for all the other components. A single determination of 5 phospholipids in an amniotic fluid sample takes about two hours. By performing simultaneous extractions it is possible to analyse 5 samples per day.     

Quantitative determination of the alkaloids ofAnabasis aphylla by thin-layer chromatography

Summary A chromatographic method has been developed for the quantitative determination of the alkaloids ofAnabasis aphylla — anabasine, aphylline, lupinine, aphyllidine, and anabasamine — and also pachycarpine in the mixture of reduction products of the high-boiling fraction of alkaloids, in a thin layer of alumina.V. I. Lenin Tashkent State University. Translated from Khimiya Prirodnykh Soedinenii, No. 6, pp. 772–776, November–December, 1976.