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PubMed2000

Investigation and analytical application of the reactions of eriochrome cyanine R with fluvoxamine and fluoxetine.

Eriochrome cyanine R (ECR) reacts with fluvoxamine (FXM) and fluoxetine (FXT) forming coloured ion-association compounds. The composition of the compounds, studied by spectrophometric methods showed that the molar ratio ECR:FXM = 1:2 and ECR:FXT = 1:2. The formation and extraction conditions of the compounds were established. The compounds were characterised by UV, VIS, and IR spectrometry. It was found that the compounds are insoluble in water but quantitatively extracted into buthanol. Under the optimal experimental conditions fluvoxamine and fluoxetine were determined in the range 2-40 microg/ml and 2-20 microg/ml, respectively. The relative standard deviation is about +/- 2%.

Benzenesulfonates↗
PubMed2001

First derivative spectrophotometric, TLC-densitometric, and HPLC determination of acebutolol HCL in presence of its acid-induced degradation product.

Three methods are presented for the determination of acebutolol HCl in presence of its acid-induced degradation product. The first method was based on measurement of the first derivative amplitude of acebutolol HCl at 266.6 nm. The second method was based on separation of acebutolol HCl from its acid-induced degradation product followed by densitometric measurement of the spots at 230 nm. The separation was carried out on silica gel 60 F254, using ethanol-glacial acetic acid (4:1, v/v) as mobile phase. Second order polynomial equation was used for the regression line. The third method was based on high performance liquid chromatographic (HPLC) separation of acebutolol HCl from its acid-induced degradation product on a reversed phase, ODS column using a mobile phase of methanol-water (55:45, v/v) with UV detection at 240 nm. The first derivative spectrophotometric method was utilized to investigate the kinetics of the acid degradation process at different temperatures.

Acebutolol↗
PubMed1996

The effect of Fe3+ ion on benzylpenicillin in micellar and nonmicellar aqueous solutions.

The effect of Fe3+ ions on the hydrolysis of benzylpenicillin in aqueous solution below and above the critical micellar concentration (c.m.c. = 0.26 M) has been studied. The catalytic effect of Fe3+ ions on hydrolysis of this drug has been demonstrated; the reaction rate constant, calculated from UV absorption data of non-micellar solutions, decreases with concentration. It is likely that Fe3+ ions form complexes with the products of degradation. The bright brown slightly soluble product formed in micellar solutions was analyzed by UV - Vis reflection, IR and mass spectroscopy and, in agreement with the results of elemental analysis, is postulated to be an octahedral binuclear complex, Fe2BP4(OH)2. This study has been linked with the clinical observation that prolonged treatment with penicillin leads to anemia.

Catalysis↗
PubMed2000

Comparison of the composition of some petroleum samples which may be applied for skin and mucous membrane treatment.

A particular Croatian petroleum (sample P1) and its three derivatives (samples P2, P3 and P4), potentially applied as healing preparations for skin and mucous membrane treatment, were studied in order to learn their composition and to discriminate them according to two criteria: composition of natural petroleum compounds, and lacking aromatics. Elemental (C, H, N and S) and group composition (by LC, UV/VIS, IR and 1H NMR) were determined and the single component distributions were analyzed (by GC) and identified (by GC-MS). Focussed saturated compounds (n-alkanes, pristane and phytane, drimanes/eudesmanes, steranes and hopanes) were studied in order to emphasize the preservation or destruction of genuine petroleum structures in derivatives. Samples P2 (petroleum-brownish color, petroleum like smell) and P3 (colorless, transparent, slight pine-like odor), were found, now constituting petroleum, to still be composed of the components of their native structure. Compared to sample P1, they were missing light and heavy compounds. While sample P2 contained different compound classes, sample P3 comprised exclusively saturated hydrocarbons, satisfying pharmacopoeia's requirement regarding the low aromatics content. Almost a half of sample P3 was composed of cyclic moieties, including terpenoids, possibly responsible for the odor. Samples P1, P2 and P3 were found rather rich in steranes. Sample P4 (colorless, transparent, no smell) was found denaturalized. In spite of high similarity in bulk properties to sample P3, it comprised no detectable amount of n-alkanes, pristane and phytane, or drimanes/eudesmanes, steranes and hopanes (although found rich in oligocycles).

Administration, Topical↗
PubMed2000

First derivative spectrophotometric and LC determination of benoxinate hydrochloride and its degradation products.

Two methods are presented for the determination of benoxinate HCI and its acid and alkali-induced degradation products using first derivative (1D) spectrophotometry with zero-crossing measurements and liquid chromatography. Benoxinate HCl was determined by measurement of its first derivative amplitude in mcllvaine's-citric acid phosphate buffer pH 7.0 at 268.4 and 272.4 nm in the presence of its alkali- and acid-induced degradation products, respectively. The acid- and alkali-induced, degradation products were determined by measurement of their first derivative amplitude in the same solvent at 307.5 nm. The LC method depends upon using a mu bondapak CN column with a mobile phase consisting of acetonitrile-water triethylamine (60:40:0.01, v/v) and adjusted to apparent pH 7. Quantitation was achieved with UV detection at 310 nm based on peak area. The proposed methods were utilized to investigate the kinetics of the acidic and alkaline degradation processes at different temperatures. The pH-rate profile of degradation of benoxinate HCl in Britton-Robinson buffer solutions was studied.

Anesthetics, Local↗
PubMed2003

Isolation, purification and partial characterization of antibacterial activities produced by a newly isolated Streptomyces sp. US24 strain.

A new actinomycete strain designated US24 producing antibacterial activities against Gram-positive and Gram-negative bacteria was isolated from Tunisian soil. Culture characteristic studies strongly suggested that the US24 strain belonged to the genus Streptomyces. Analysis of the nucleotide sequence of the 16S rRNA gene of the Streptomyces sp. US24 strain showed high similarity (98%) with the 16S rRNA gene of Streptomyces caelestis which produces two antibiotics, niddamycin and celesticetin. Study of the influence of different nutritional compounds on antibiotic biosynthesis showed that the highest antibacterial activities were obtained when starch at 1% (w/v) was used as sole carbon source in the presence of traces of mineral oligoelements. Application to the supernatant culture of the Streptomyces sp. US24 strain of various separation steps led to isolation of two pure active molecules having a retention time of 34 and 37.26 min, respectively. P(34 min) possessed antibacterial activity against Gram-positive and Gram-negative bacteria, whereas P(37.26 min) inhibited only Gram-positive bacteria. Partial characterization of the P(34 min) molecule using spectroscopic studies showed that this active molecule is different from the two antibiotics produced by the S. caelestis strain.

Anti-Bacterial Agents↗
PubMed2001

Reaction of Lys-Tyr-Lys triad mimics with benzylpenicillin: insight into the role of Tyr150 in class C beta-lactamase.

Small and simple molecules mimicking a Lys-Tyr-Lys triad and some 'mutant' derivatives were designed and synthesized. These-compounds react with benzylpenicillin in water (75mM phosphate buffer, pH 7), apparently through general base assistance by the phenolic moiety. Class C beta-lactamase has a Lys-Tyr-Lys triad in its active site, and our finding gives some insight into the role of this triad in the enzymatic beta-lactam hydrolysis mechanism.

Enzyme Inhibitors↗
PubMed2002

Phytoecdysteroids from the juice of Serratula coronata L. (Asteraceae).

Seven phytoecdysteroids have been isolated from Serratula coronata L. One of them is a new phytoecdysteroid, 3-epi-20-hydroxyecdysone. Two further ecdysteroids, 20-hydroxyecdysone 22-acetate and taxisterone, are isolated from this species for the first time in addition to the typical S. coronata ecdysteroids, 20-hydroxyecdysone, ecdysone, ajugasterone C and polypodine B. The juice squeezed from aerial parts of fresh plants of S. coronata was extracted with ethyl acetate. The ecdysteroids were isolated by a combination of chromatographic techniques (mainly HPLC) and identified by 1D and 2D (1)H and (13)C NMR experiments and mass-spectrometry. The biological activities of 3-epi-20-hydroxyecdysone (EC(50)=1.6 x 10(-7) M), taxisterone (EC(50)=9.5 x 10(-8) M) and ajugasterone C (EC(50)=6.2 x 10(-8) M) have been determined in the Drosophila melanogaster B(II) bioassay for ecdysteroid agonist activity.

Asteraceae↗
PubMed2003

Design and synthesis of 4H-3-(2-phenoxy)phenyl-1,2,4-triazole derivatives as benzodiazepine receptor agonists.

A series of new 5-substituted analogues of 4H-3-(2-phenoxy)phenyl-1,2,4-triazole and its chlorinated derivatives was designed and prepared. Conformational analysis and superimposition of energy minima conformers of the compounds on estazolam, a known benzodiazepine receptor agonist, revealed that the main proposed benzodiazepine pharmacophores were well matched. Rotarod and pentylenetetrazole-induced lethal convulsion tests showed that the introduction of an amino group in position 5 of 1,2,4-triazole ring especially in chlorinated derivatives had the best effect which was comparable with diazepam.

Animals↗
PubMed2002

Improvement of an ultrasound assisted method for the analysis of total carbohydrate in environmental and food samples.

The determination of the carbohydrate content of environmental and food samples, performed by spectroscopic and chromatographic methods, needs a preliminary hydrolysis which converts polysaccharides into monosaccharides prior to the analytical measurement. In this paper, a modified procedure of the ultrasound-assisted method for the determination of total carbohydrates, published by the same authors in a previous paper, is presented and discussed. The modified procedure represents an improvement with respect to the previous one because it shortens the hydrolysis time and the colorimetric determination times through the use of two acid media (formic and acetic acid) that also allows quantitative recoveries of total carbohydrates from food and environmental samples.

Acetates↗
PubMed2000

Spectroscopic studies of some novel CuI and CuII complexes derived from the tribochemistry reactions of Kbr, KI and CaI2 with CuII-Girard's T complex [Cu(GT)Cl2(H2O)2(EtOH)]Cl.H2O.

Novel CuI and CuII complexes derived from the tribochemistry reactions of [Cu(GT)Cl2(H2O)2(EtOH)Cl.H2O with KBr, KI and CaI2 have been isolated and characterized. The reactions of KI and CaI2 with [Cu(GT)Cl2(H2O)2(EtOH)]Cl.H2O in the solid state are accompanied by colour change, reduction of CuII to CuI and substitution of the chloride by iodide ions. Also, the tribochemistry reaction of KBr with the CuII-GT complex is accompanied by change in colour, substitution of chloride by bromide ions but no reduction has been occurred. All the isolated solid complexes have been characterised by spectral (UV-vis, IR, 1H-NMR), magnetic and thermal measurements. The effect of the variation of the ratio between alkali and/or alkaline earth metal halides (KI, KBr, and CaI2) and the CuII-GT complex has also been investigated.

Betaine↗
PubMed2001

Spectral studies on metal-ligand bonding in complexes of 1-acetyl-2-(coumariniminecarboxamide-3-yl)hydrazine.

Several new transition metal complexes derived from 1-acetyl-2-(coumariniminecarboxamide-3-yl)hydrazine (HL) have been prepared and characterized by elemental analyses, 1H-NMR, magnetic susceptibility, IR, UV, EPR and thermal analyses. Stereochemistries are proposed for the complexes on the basis of the spectral and magnetic studies. The i.r. data indicate that the carbonyl oxygen of the carboxamide constituents chelating backbone in most complexes. The visible and EPR spectral studies indicated that the Cu(II) complexes have a tetragonal geometry. From the EPR spectrum of the Cu(II) complexes, various parameters were calculated.

Benzopyrans↗
PubMed2000

Spectroscopic study of low temperature interactions in metal-organic co-condensates.

The results on spectroscopic study of low temperature interactions of metal atoms, small clusters and nanoparticles with different organic and inorganic substances in the temperature range 12-300 K are presented. Complexation and reactions of atoms and clusters of magnesium, samarium and silver with carbon dioxide, ethylene and some mesogenic cyanophenyls were studied by the technique of matrix isolation and low temperature co-condensation of metal and ligand vapors, low temperature UV-Vis, IR- and ESR-spectroscopy in combination with quantum chemistry calculations. It was shown that cryochemical reactions of metal particles of different sizes reflected the system's redundant energy.

Carbon Dioxide↗
PubMed2000

Spectroscopic study of low temperature interactions in Sm-mesogenic cyanophenyl co-condensates.

The IR- and UV-Vis spectroscopic study of samarium-mesogenic 4-pentyl-4'-cyanobiphenyl low temperatures co-condensates was made in temperature range 90-300 K. Two labile complexes with different metal/ligand ratio of 1:2 and 1:1 were found. They were characterized by methods of IR- and UV-spectroscopy. The solid state transformation of complex Sm(5CB)2 to Sm(5CB) was shown to take place at 170-210 K. The kinetics of the process revealed a wide distribution of complex reactivity and of reaction activation energy.

Biphenyl Compounds↗
PubMed2002

Spectral studies and molecular orbital PPP-calculations of some azo-dyes.

The UV, IR and 1H-NMR spectra of some 4-(R-phenyl azo) 1-hydroxy 2-naphthoic acid derivatives are studied. The effects of substituent groups and the solvent polarity on electronic spectral, IR bands and 1H-NMR proton chemical shifts are considered, the molecular orbital calculations obtained are rationalized quantitatively with that obtained practically using the PPP-model with configuration interaction (CI).

Azo Compounds↗
PubMed2002

Photochemical reaction monitoring by ultra-violet spectrophotometry.

Within the framework of the monitoring of the trichloroacetylchloride (TCAC) photosynthesis, ultra-violet (UV) spectrophotometry is proposed as a simple and rapid tool allowing, in real time, the control of the process efficiency. A good correlation has been obtained between the results acquired by this alternative method and the standard gas chromatography.

Chloroacetates↗
PubMed2003

Molecular complexes of antipsychotic pharmaceutical parent molecule phenothiazine and unsaturated acid anhydrides.

The charge-transfer complexes (CTC) between a parent molecule of antipsychotic pharmaceuticals, phenothiazine, and seven unsaturated acid anhydrides, 1,4,5,8-naphtalenetetracarboxylic dianhydride, diphenic anhydride, maleic anhydride (MA), 3,4,5,6-tetrahydrophthalic anhydride (THPA), 3-hydroxy-1,8-naphthalic anhydride (HONA), 4-chloro-1,8-naphthalic anhydride (ClNA), and 1,8-naphthalic anhydride (NA) were studied using IR and UV spectroscopy. Stability constants (K) at different temperatures were measured, and based on the K's DeltaH and DeltaS were calculated. The values of electron affinity (E(A)) of anhydrides were obtained according to Mulliken's theory. The results show that phenothiazine is an excellent donor and has strong ability to complex with the carbonyl group, and the E(A) values have good linear relationships with DeltaH and K, respectively. The solvent effect on CTCs was also determined and explained. The CTC of phenothiazine-succinic anhydride (SA) was studied under the same conditions. It was deduced from the results obtained that there were two charge-accepting centers in the unsaturated acid anhydrides when they formed CTCs with phenothiazine. The first one was carbon atom of the two carbonyl groups and the second one was their -C=C- in the molecules.

Anhydrides↗