Optimization of a CUPRAC-Based HPLC Postcolumn Assay and Its Applications for Ginkgo biloba L. Extracts.

The aim of the present work was to improve and validate the HPLC-CUPRAC postcolumn method for the evaluation of active antioxidant markers from the acetonic extracts of Ginkgo biloba leaves. Improvement of the HPLC online assay was performed by evaluating the suitable loop temperature, the reaction loop length, and the impact of flow rate. Separation of the analytes was performed by the HPLC method on an ACE C18 analytical column using a gradient elution program. The separated antioxidant markers in the extracts reacted with copper(II)-neocuproine (Cu(II)-Nc) reagent in the postcolumn reaction coil. The reagent was reduced by antioxidants to the copper(I)-neocuproine (Cu(I)-Nc) chelate with a maximum absorption at 450 nm. Validation experiments confirmed sufficient precision, sensitivity, and effectiveness of the corresponding method, which could be used for further evaluations of active antioxidant compounds in similar plant materials.

Application of high-performance liquid chromatography for research of salicin in bark of different varieties of Salix.

Willow (Salix L.) species are widely spread in Lithuanian natural dendroflora. Willow bark contains active substances known for anti-inflammatory properties and is known as a phytotherapeutic precursor of aspirin. Bark extracts are components of analgesic and antirheumatic preparations. Therapeutic effectiveness is associated with salicin (2-(hydroxymethyl)phenyl-beta-D-glucopyranoside), which turns into salicylic acid. Increasing attention to natural preparations gives primary importance to research of plants. This study focused on 12 willow taxa and employed routine pharmacopoeia methods. High-performance liquid chromatography method was applied for the analysis of bark extractions. The investigation revealed that not all willow species accumulated a therapeutically sufficient amount of salicin. Bark samples were investigated after 1- and 2-year growth in autumn and spring. Salicin content ranged from 0.08 to 12.6%. Higher contents of active materials were determined in autumn and in 2-year-old willows. Certain willow taxa (Salix alba L., Salix mollissima L., Salix triandra L., Salix viminalis "Americana", Salix dasyclados L.) possessed extremely low salicin amounts. In the second year, analysis covered 32 willow species. Results indicated striking differences in salicin amounts (from 0.04% in Salix viminalis "Americana" to 12.06% in Salix acutifolia). Willow species, plant age, and season should be considered when collecting medicinal plant material. The amount of salicylates in 2-year-old willow bark collected in autumn exceeded by 25% that in 1-year-old willow bark collected in spring. Bark of some analyzed willow species contained the amount of salicylates too low for using as anti-inflammatory or antipyretic remedy.

[The chemical-toxicological research of psychostimulator mixture by thin-layer chromatography]. / Psichostimuliatoriu misinio cheminis-toksikologinis tyrimas plonasluoksnes chromatografijos metodu.

With increasing number of intoxications with some preparations at the same time there is a lack of literature data about chemical-toxicological research of psychostimulator mixture. The aim of the study was to analyze the possibility of identification of four preparations in the mixture. The thin-layer chromatography method was used. The most acceptable solvent systems were determined: ethylacetate-methanol-conc. ammonia hydroxide (40:4:2:25) and dioxane-benzenum-conc. ammonia hydroxide-acetone (28:14:2:25).

[UV spectrophotometric research of drug mixture in sudden poisoning cases]. / Vaistu misinio UV-spektrofotometrinis tyrimas uminiu apsinuodijimu atvejais.

UNLABELLED: The objective of this research--to develop the methodics for analysis of amitriptyline, fluoxetine and codeine in the mixture. RESULTS: The analytical method of amitriptyline, codeine and fluoxetine in the mixture identification and quantitative determination using ultraviolet spectrophotometry was established. Preparations in the mixture can't be separated, because material ultraviolet light peaks are in insufficient distance and therefore cover one another. The maximum of ultraviolet light absorption for amitriptyline is at 217-220 and 238-240 nm; fluoxetine--at 226-228 nm; codeine--at 224-248 and 284-286 nm. Using ultraviolet spectroscopy it's possible to identify amitriptyline, fluoxetine and codeine only after separating mixture components by thin-layer chromatography, the same time executing cleaning of extracts from blood and urine. Using ultraviolet spectroscopy can be identificated at least 0.5 micro g/ml amitriptyline, 1.5 micro g/ml fluoxetine and 1.0 microg/ml codeine. The intervals of the quantitative determination: 5-25 microg/ml amitriptyline; 5-30 microg/ml fluoxetine; 100-300 microg/ml codeine; relative error of the measurement, when confidence level is 95%, is from 0.66 to 1.2% for amitriptyline; from 0.66 to 1.45% for fluoxetine; from 0.33 to 0.88% for codeine. Standard deviation is from 1.15 to 2.08% for amitriptyline; from 1.15 to 2.52% for fluoxetine; from 0.57 to 1.53% for codeine. Molar absorption coefficients for all three preparations in distillated water were determinated. CONCLUSIONS: recommended methodology suits for mixture, extracted from biological liquids, components separation, identification and quantitative determination.

[Poisonings with psychotropic drug mixtures: analysis using the thin-layer chromatography method]. / Apsinuodijimu psichotropiniu vaistu misiniu tyrimas plonasluoksnes chromatografijos metodu.

It is observed increase in number of remedy intoxications in Lithuania, especially important is intoxication with psychotropic drugs and their mixtures. The thin-layer chromatography (TLC) method was proposed for separation and identification of drugs in mixture aminazine: nitrazepam: barbamylum. The mixture of these drugs excreted from body fluids (blood and urine) was investigated by TLC. Most acceptable these mobile phases: 1. Diethyl ether: dioxane--40:60. Rf values for drugs: aminazine 0.23-0.25; barbamylum 0.85-0.9; nitrazepam 0.75-0.8. 2. Diethyl ether: NH3 (25%): benzenum--80:10:10. Rf values for drugs: aminazine 0.55-0.58; barbamylum 0.32-0.35; nitrazepam 0.17-0.2.

[Analysis of benzodiazepine derivative mixture by gas-liquid chromatography]. / Benzodiazepino dariniu misinio analize duju ir skysciu chromatografijos metodu.

The analysis of mixture of benzodiazepine derivates (chlordiazepoxide, flunitrazepam, medazepam, nitrazepam, oxazepam and tetrazepam) by gas--liquid chromatography (GLC) in purpose to separate and identify these psychotropic drugs in mixture is presented in this article. The experiment was carried out in vitro, accommodating this method for identification and separation of drugs, isolated from biological objects (blood and urine). Referring to data of annual reports of chemical investigations (1) above-mentioned psychotropic drugs are very frequent among drug intoxication. In most cases they are detected in the mixture of the same or different pharmacological group, and this causes difficulty for separation and identification. The analysis of the mixture was carried out by GLC, which is widely used in practice of forensic-chemical examination. Adsorbents and stationery phases were changed; the conditions and parameters of chromatography were modified, in purpose totally separate preparations in the mixture. For the separation and identification of all three preparation the column packed with Inerton Super with stationary phase 3% OV-17 is suitable. The column temperature-290 degrees C. The mixture of these drugs was excreted from body fluids (blood and urine) in vitro and investigated by GLC under these conditions. The results of investigation were similar.

[Ultraviolet spectrophotometric determination of psychotropic drug mixtures]. / Psichotropiniu vaistu misinio tyrimas ultravioletines spektrofotometrijos metodu.

The mixture of psychotropic drugs aminazine, barbamylum and nitrazepam using ultraviolet (UV) spectrophotometric method was researched. As the solvent, most acceptable for identification and differentiation of these preparation was found 0.1N solution of sulphuric acid. By measuring the optical density of the solutions in different concentration the calibration diagrams for all preparations were made. The standard deviation, by determining the quantity of aminazine is 2.8; 4.0; 4.3; barbamylum--1.0; 2.5; 1.15; nitrazepam--2.64; 1.0; 1.35.