GLC-MS Methods Research Articles

MYCOSTATIC ACTIVITY OF EXTRACTS FROM LEAVES OF PLANTAGO MEDIA L. AND PLANTAGO ALTISSIMA L.

A variety of drugs are widely used to treat fungal infections. Mostly they are products of chemical synthesis, but recently, due to the increased resistance of fungi to many synthetic drugs, the relevance of the use of herbal remedies in the complex treatment of both skin infections and deep mycoses has been increasing. The aim of our research was to study the chemical composition of the lyophilic extracts of Plantago media and Plantago altissima of the flora of Ukraine by HPLC and GLC-MS methods and also mycostatic activity of ethanol and lyophilic extracts of the studied plants. As a result of the research, aucubin iridoid was detected in the lyophilic extracts of both species. There were also detected 15 polyphenolic compounds among which prevails acteoside, plantamayoside, ferulic and chlorogenic acid. Alcohol and lyophilic extracts of P. media and P. altissima showed mycostatic activity to all studied strains of yeast, dermatophytic fungi and aspergillus. The mycostatic effect of alcoholic extracts of P. media and P. altissima was more evident in comparison with the mycostatic effect of lyophilic extracts. The most evident antifungal effect was presented by alcoholic extract of P. media in relation to the clinical strain of Aspergillus oryzae (18.0±1.0 mm), and alcoholic extract of P. altissima to the clinical strain of Malassezia sp. (18.0±0.5 mm). The data obtained indicate a wide range of mycostatic effects of Plantago media and Plantago altissima extracts and the prospectivity of these objects for practical use in medicine.

GLC-MS investigations on cardenolide genins

A new GLC-MS method for the separation and identification of cardenolide acetates in hydrolyzed plant extracts was established. The method was shown to be selective and linear in the range from 10 μg to 5 mg/ml. Detection limits in a selected ion modus (SIM) were determined to be 5 μg/ml for digitoxigenin acetate, digoxigenin diacetate and diginatigenin triacetate and 1 μg/ml for gitoxin diacetate. Recovery rates were determined to be 96%. MS-fragmentation revealed that cardenolides with different hydroxylation patterns can be differentiated by using distinct mass fragments as indicators. While 12 β-hydroxylated cardenolides are characterized by m/z 201 and 229, cardenolides without this function fragment mainly to m/z 203 and 231. Δ5,6-unsaturated cardenolides (xysmalogenin acetate) or 5α-cardenolides (uzarigenin acetate) show fragmentation patterns similar to those of saturated or 5β-cardenolides.

GLC-MS of reduced, acetylated, and methylated (2 → 4)- and (2 → 8)-linked disaccharides of 3-deoxy- [formula omitted]- manno-octulopyranosonic acid (Kdo)

Synthetic α- and β-(2 → 4)- and α- and β-(2 → 8)-linked disaccharides of 3-deoxy- pD - manno-octulopyranosonic acid (Kdo), of which the synthesis of the β-(2 → 4)-linked compound is described here, were used to develop a simple GLC-MS method for the determination of their anomeric configuration. The GLC and GLC-MS data for the reduced and acetylated or methylated derivatives of the above compounds indicate the α-linked synthetic disaccharides to be identical to those isolated from bacterial lipopolysaccharides.

Bioequivalence of two Thorazine Tablet Formulations Using Radioimmunoassay and Gas Chromatographic-mass Spectrometric Methods

Two analytical methods for the analysis of chlorpromazine (CPZ), a radioimmunoassay (RIA) and a GLC-MS method, were compared in a bioequivalence study of two CPZ tablet formulations (Thorazine: film coated and sugar coated). Thirty-six nonsmoking, healthy, male volunteers completed the study. Each subject ingested single doses (2 × 25 mg) of the test (T) and the reference (R) formulations in a two-way crossover design with a two-week drug-free interval between doses. Following each administration, plasma concentrations of CPZ were monitored over a period of 24 h by both RIA and GLC-MS methods. Plasma concentrations and pharmacokinetic parameters determined by either analytical method showed wide intersubject variation, with the GLC-MS data showing relatively higher magnitude of intersubject variation than the RIA data. In general, plasma concentrations measured by RIA were significantly different from those measured by GLC-MS (paired t tests: p < 0.0001). As indicated by the regression analysis, concentrations determined by RIA were 1.3–1.4 times higher than those determined by GLC-MS. There were strong and significant correlations between the two methods for both T and R (r > 0.75: p < 0.0001). Similar statistical relationships were found between the plasma concentrations of CPZ determined by the two methods at each sampling time and the bioequivalence parameters area under the plasma level versus time curves up to the last measurable concentration (AUC0t) and the maximum plasma concentration (Cmax). Bioequivalence parameters AUC0t, AUC0∞, and (Cmax). determined separately from the data obtained by the two methods for the two formulations were examined by analyses of variance (ANOVA) and other criteria and tests for bioequivalence. Results of ANOVA, confidence intervals of test/reference ratios of AUC0t, AUC0∞, and Cmax, and statistical tests for bioequivalence indicated that, except for Cmax by GLC-MS, data generated by both methods indicated bioequivalence of the two formulations (i.e., test/reference ratio was within 100 ± 20%). The experiments suggest that despite significant differences between the absolute plasma concentration values obtained, both methods yielded data for the two formulations which demonstrated that they were bioequivalent.

Distribution of Substituents in Methylcellulose

Abstract The distribution of methyl groups in methylcelluloses (DS 1.7) has been determined. The partially methylated monosaccharides obtained on complete hydrolysis of methylcellulose were converted into alditols by reduction. They were identified as their acetates or trimethylsilyl ethers by gas-liquid chromatography-mass spectrometry and quantified by gas-liquid chromatography. In addition, 13C-nuclear magnetic resonance spectra of native and hydrolyzed methylcelluloses as well as the partially methylated alditols obtained by hydrolysis and reduction were analyzed. The main glucose methyl ethers obtained were in decreasing order 2,6-, 2,3,6-, 2-, 6-, and 2,3-. The 2-and 6-positions were occupied by methyl groups in 70.0 and 61.5%, respectively, while the 3-position contained only 37.4%. The GLC-MS method gave a more accurate determination of the distribution of methyl groups in methylcellulose compared to NMR spectroscopy.

A pharmacokinetic study of trifluoperazine in two ethnic populations.

The single dose pharmacokinetics of trifluoperazine (5 mg, Stelazine) were investigated in black (n = 25) and white (n = 32) healthy male subjects. Plasma samples were harvested over 24 h and analysed by a GLC-MS method. There were wide intersubject variations in all pharmacokinetic parameters examined, including Cmax, AUC, apparent oral volume of distribution at steady state, and elimination half-life. For each of these parameters the distribution was positively skewed in both blacks and whites and the geometric mean gave a better estimate of central tendency than the corresponding arithmetic mean. In all pharmacokinetic parameters examined there was no significant difference detected between black and white subjects or between smokers and non-smokers.

Analytical Problems in the Investigation of Unsaturated Acids Conversion II: Determination of Position Isomers, Conjugated Unsaturated Bonds and Composition of Fatty Acids

AbstractThe paper discusses the methods of determination of the position of unsaturated bonds in a chain of acids, the determination of the sum of conjugated unsaturated bonds and the composition of the fatty acids. The position of unsaturated bonds in acids of modified oils may be determined most quickly by the method of pyrrolidide derivatives and determinations by the GLCMS method. The content of conjugated bonds had been determined by standardized method of UV spectrometry, and the composition of the fatty acids had been determined by gas chromatography.

Analysis of chlorpromazine in plasma: Effect of specimen storage

Two analytical methods for the analysis of chlorpromazine (CPZ), a radioimmunoassay (RIA) and a GLC-MS method, were compared in a bioequivalence study of two CPZ tablet formulations (Thorazine: film coated and sugar coated). Thirty-six nonsmoking, healthy, male volunteers completed the study. Each subject ingested single doses (2 × 25 mg) of the test (T) and the reference (R) formulations in a two-way crossover design with a two-week drug-free interval between doses. Following each administration, plasma concentrations of CPZ were monitored over a period of 24 h by both RIA and GLC-MS methods. Plasma concentrations and pharmacokinetic parameters determined by either analytical method showed wide intersubject variation, with the GLC-MS data showing relatively higher magnitude of intersubject variation than the RIA data. In general, plasma concentrations measured by RIA were significantly different from those measured by GLC-MS (paired t tests: p < 0.0001). As indicated by the regression analysis, concentrations determined by RIA were 1.3–1.4 times higher than those determined by GLC-MS. There were strong and significant correlations between the two methods for both T and R (r > 0.75: p < 0.0001). Similar statistical relationships were found between the plasma concentrations of CPZ determined by the two methods at each sampling time and the bioequivalence parameters area under the plasma level versus time curves up to the last measurable concentration (AUC0t) and the maximum plasma concentration (Cmax). Bioequivalence parameters AUC0t, AUC0∞, and (Cmax). determined separately from the data obtained by the two methods for the two formulations were examined by analyses of variance (ANOVA) and other criteria and tests for bioequivalence. Results of ANOVA, confidence intervals of test/reference ratios of AUC0t, AUC0∞, and Cmax, and statistical tests for bioequivalence indicated that, except for Cmax by GLC-MS, data generated by both methods indicated bioequivalence of the two formulations (i.e., test/reference ratio was within 100 ± 20%). The experiments suggest that despite significant differences between the absolute plasma concentration values obtained, both methods yielded data for the two formulations which demonstrated that they were bioequivalent.

The determination of homovanillic acid in human and rat urine using gas chromatography with flame ionization and mass spectrometric detection

New gas-liquid chromatographic (GLC) methods were developed for the assay of homovanillic acid (HVA) in human and rat urine. The methods are based on the use of extraction and efficient column purifications (silicic acid and lipophilic Sephadex) before quantitative GLC analysis using either a flame ionization detector (FID) with 3-methoxy-4-hydroxy-phenylpropionic acid as internal standard or mass spectrometric (MS) detection using a deuterated HVA derivative as carrier and internal standard. The precision was found to be ± 3–5 per cent (S.D.) for the GLC-FID method and ± 10 per cent (S.D.) for the GLC-MS method. The main advantage over existing gas chromatographic methods is about a 100-fold increased sensitivity which allows accurate quantitation of normal or decreased levels of HVA.

The Essential Oils of Lilium Makinoi Koidz. and L. auratum Lindle.

The essential oils of L, Makinei and L. auratum were examined in detail. From L. Makinei 12 compounds were isolated and confirmed by direct comparison with the authentic samples, and 4 trace components were identified by GLC-MS method. Among them 2, 6, 6-trimethyl-2-vinyl-5-ketotetrahydropyran (2) was newly isolated as natural product. On the other hand, 25 compounds were isorated from L, auratecm and characterized, and 6 trace components were also identified.The essential oil of L. Makinoi. contained cis-2, 6, 6-trimethyl-2-vinyl-5-hydroxytetrahydropyran (1) as the'main component, along with small amount of linalool relatively large amounts of the other oxidation compounds of linalool, and small amounts of a few phenolic compounds. The essential oil of L. auratum, on the contrary, contained linalool, many phenolic compounds in large guantities, and some oxidation compounds of linalool in smail quantities.

The Use of Gas Phase Analytical Methods For the Analysis of Phospholipids

Gas phase analytical procedures have been developed for the direct study of phospholipids. Glycerophospholipids undergo thermal cleavage to yield diglycerides. The reaction apparently involves an ortho acid (ester) structure as an intermediate. The phosphate ester group was also eliminated from silylated sphingomyelins when these compounds were subjected to direct GLC analysis. The derivatives corresponded to dehydration products. Ceramides were investigated by GLC, because of their structural relationship to sphingomyelins. It was possible to obtain TMSi derivatives of ceramides which could be studied by GLC and GLC-MS methods. The mass spectra of the derivatives showed characteristic fragmentation patterns that permitted their identification in terms of specific structural relationships.

The Glc Separation of Indole Amines and Indole Alcohols as Heptafluorobutyryl Derivatives

Abstract Indole amines and indole alcohols were converted to heptafluoro-butyryl (HFB) derivatives by an acyl transfer reaction with heptafluoro-butyrylimidazole. The indole NH group as well as all amino and hydroxyl groups were acylated. The HFB derivatives have excellent gas chroma-tographic properties and can be used with either hydrogen flame or electron capture detection systems. Mass spectra of the HFB derivatives of biologic N, N-dialkyl indole amines are very characteristic; these compounds can be identified easily by GLC-MS methods.