Determination of chlorpheniramine in human plasma by HPLC-ESI-MS/MS: application to a dexchlorpheniramine comparative bioavailability study

In the present study a fast, sensitive and robust validated method to quantify chlorpheniramine in human plasma using brompheniramine as internal standard (IS) is described. The analyte and the IS were extracted from plasma by LLE (diethyl ether-dichloromethane, 80:20, v/v) and analyzed by HPLC-ESI-MS/MS. Chromatographic separation was performed using a gradient of methanol from 35 to 90% with 2.5 mm NH(4)OH on a Gemini Phenomenex C(8) 5 mu m column (50 x 4.6 mm i.d.) in 5.0 min/run. The method fitted to a linear calibration curve (0.05-10 ng/mL, R > 0.9991). The precision (%CV) and accuracy ranged, respectively: intra-batch from 1.5 to 6.8% and 99.1 to 106.6%, and inter-batch from 2.4 to 9.0%, and 99.9 to 103.1%. The validated bioanalytical procedure was used to assess the comparative bioavailability in healthy volunteers of two dexchlorpheniramine 2.0 mg tablet formulations (test dexchlorpheniramine, Eurofarma, and reference Celestamine (R), Schering-Plough). The study was conducted using an open, randomized, two-period crossover design with a 2 week washout interval. Since the 90% confidence interval for C(max) and AUC ratios were all within the 80-125% interval proposed by ANVISA and FDA, it was concluded that test and reference formulations are bioequivalent concerning the rate and the extent of absorption. Copyright (C) 2009 John Wiley & Sons, Ltd.

Rapid Screening and Identification of Polar Constituents from Brazilian Arnica Lychnophora sp by LC-UV/DAD-ESI-MS and LC-UV/DAD-ESI-MS/MS Analysis

This paper describes an analytical method for the rapid screening and identification of the phenolic constituents present in the polar extracts of different Lychnophora spp. using LC-UV/DAD-ESI-MS and LC-UV/DAD-ESI-MS/MS. Compounds were identified based on UV, retention time, MS experiments and MS/MS of precursor ion or standard. On-line phytochemical investigation of Lychnophora spp. allowed for the identification of flavonoids, chlorogenic acid derivatives and lactones. Some of the observed compounds were for the first time identified in Lychnophora species in a fast analytical procedure. The data obtained here may be helpful to the investigation of polar constituents from other Lychnophora species.

Reactivity of Beer Bitter Acids Toward the 1-Hydroxyethyl Radical as Probed by Spin-Trapping Electron Paramagnetic Resonance (EPR) and Electrospray Ionization-Tandem Mass Spectrometry (ESI-MS/MS)

The iso-alpha-acids or isohumulones are the major contributors to the bitter taste of beer, and it is well-recognized that they are degraded during beer aging. In particular, the trans-isohumulones seem to be less stable than the cis-isohumulones. The major radical identified in beer is the 1-hydroxyethyl radical; however, the reactivity between this radical and the isohumulones has not been reported until now. Therefore, we studied the reactivity of isohumulones toward the 1-hydroxyethyl radical through a competitive kinetic approach. It was observed that both cis- and trans-isohumulones and dihydroisohumulones are decomposed in the presence of 1-hydroxyethyl radicals, while the reactivities are comparable. On the other hand, the tetrahydroisohumulones did not react with 1-hydroxyethyl radicals. The apparent second-order rate constants for the reactions between the 1-hydroxyethyl radical and these compounds were determined by electron paramagnetic resonance (EPR) spectroscopy and electrospray ionization-tandem mass spectrometry [ESI(+)-MS/MS]. It follows that degradation of beer bitter acids is highly influenced by the presence of 1-hydroxyethyl radicals. The reaction products were detected by liquid chromatography electrospray ionization-ion trap-tandem mass spectrometry (LC-ESI-IT-MS/MS), and the formation of oxidized derivatives of the isohumulones was confirmed. These data help to understand the mechanism of beer degradation upon aging.

Characterization of protein hydrolysates of cosmetic use by CE-MS

Protein hydrolysates have been used as active principles in cosmetic products conferring different properties to the final formulations, which are mostly controlled by the peptide size and its amino acid sequence. In this work, capillary electrophoresis coupled to mass spectrometry analyses were carried out in order to investigate such characteristics of protein hydrolysates. Samples of different origins (milk, soy and rice) were obtained from a local company, and were analyzed without a previous preparation step. The background electrolyte (BGE) and sheath liquid compositions were optimized for each sample. The best BGE composition (860 mmol/L formic acid - pH 1.8 - in 70: 30 v/v water/methanol hydro-organic solvent) was chosen based on the overall peak resolution whereas the best sheath liquid was selected based on increased sensitivity and presented different compositions to each sample (10.9-217 mmol/L formic acid in 75: 25-25: 75 v/v water/methanol hydro-organic solvent). Most of the putative peptides in the hydrolysate samples under investigation presented molecular masses of 1000 Da or less. De novo sequencing was carried out for some of the analytes, revealing the hydrophobicity/polarity of the peptides. Hence, the technique has proved to be an advantageous tool for the quality control of industrial protein hydrolysates.

Synthesis and characterization of the [Ru(3)O(CH(3)COO)(6)(py)(2)(BPE)Ru(bpy)(2)Cl](PF(6))(2) dimer

The polymetallic [Ru(3)O(CH(3)COO)(6)(py)(2)(BPE)Ru( bpy)(2)Cl](PF(6))(2) complex (bpy = 2,2`-bipyridine, BPE = trans- 1,2-bis(4-pyridil) ethylene and py = pyridine) was assembled by the combination of an electroactive [Ru(3)O] moiety with a [ Ru( bpy) 2( BPE) Cl] photoactive centre, and its structure was determined using positive ion electrospray (ESI-MS) and tandem mass (ESI-MS/MS) spectrometry. The [Ru(3)O(CH(3)COO)(6)(py)(2)(BPE)Ru(bpy)(2)Cl] (2+) doubly charged ion of m/z 732 was mass-selected and subject to 15 eV collision-induced dissociation, leading to a specific dissociation pattern, diagnostic of the complex structure. The electronic spectra display broad bands at 409, 491 and 692 nm ascribed to the [Ru(bpy)(2)(BPE)] charge-transfer bands and to the [Ru(3)O] internal cluster transitions. The cyclic voltammetry shows five reversible waves at - 1.07 V, 0.13 V, 1.17 V, 2.91 V and - 1.29 V (vs SHE) assigned to the [Ru(3)O](-1/0/+ 1/+ 2/+3) and to the bpy (0/-1) redox processes; also a wave is observed at 0.96 V, assigned to the Ru (+2/+ 3) pair. Despite the conjugated BPE bridge, the electrochemical and spectroelectrochemical results indicate only a weak coupling through the pi-system, and preliminary photophysical essays showed the compound decomposes under visible light irradiation.

The use of electrospray ionization tandem mass spectrometry on the structural characterization of novel asymmetric metallo-organic supermolecules, based on pentafluorophenylporphyrins and ruthenium complexes

The novel asymmetric metallo-organic triads cis- and trans-[B(4-py)BPFPH(2){Ru(3)O(Ac)(6)(py)(2)}(Ru(bpy)(2)Cl}](PF(6))(2) (5a,b) for which cis- and trans-B(4-py)BPFPH(2)=5,10-bis(pentafluorophenyl)-15,20-bis(4-pyridyl)porphyrin and 5,15-bis(pentafluorophenyl)-10,20-bis(4-pyridyl)porphyrin, respectively; Ac = acetate; py = pyridine and bpy = 2,2`-bipyridine, as well as their corresponding monosubstituted dyads cis- and trans-[B(4-py)BPFPH(2){Ru(3)O(Ac)(6)(py)(2)}]PF(6) (4a,b) have been structurally characterized via electrospray ionization mass spectrometry (ESI-MS and ESI-MS/MS). The ESI-MS of dyads 4a,b display two characteristic Ru-multicomponent clusters of isotopologue ions corresponding to singly charged ions 4a,b(+) of m/z 1629 and doubly charged ions [4a,b+H](2+) of m/z 815 and the triads 5a,b are detected by ESI-MS as the intact doubly charged cluster of isotopologue ions of m/z 1039 [5a,b](2+). The ESI-MS/MS of 4a,b(+), [4a,b+H](2+) and [5a,b](2+) reveal characteristic dissociation pathways, which confirm the structural assignments providing additional information on the intrinsic binding strengths of the gaseous ions. Although the gas-phase behavior of each pair of isomers was rather similar, the less symmetric dyads 4a,b are distinguished via the (1)H NMR spectral profile of the pyrrolic signals. Exploratory photophysical assays have shown that both modifying motifs alter the porphyrinic core emission profile, opening the possibility to use these asymmetric systems as photophysical devices. (C) 2008 Elsevier Ltd. All rights reserved.

Characterization of lipopeptides from Paenibacillus sp (IIRAC30) suppressing Rhizoctonia solani

The main aim was to identify the active compound against Rhizoctonia solani produced by the cassava endophyte Paenibacillus sp. IIRAC-30. The compounds produced were extracted with ethyl acetate and purified by Sephadex column prior to analysis by Q-TOF mass spectrometry. A C(15)-lipopeptide with an estimated molecular weight of 1036 Da and homologues were identified. The lipopeptide had a cyclic structure, which was deduced by interpreting the ESI-MS/MS spectra of main protonated homologues containing 15:0 FA, and the amino acid composition was Glu-Leu-Leu-Val-Asp-Leu-Leu. Therefore, the lipopeptides produced by isolate IIRAC-30 was characterized as a surfactin series. Thus, the main mechanism used by Paenibacillus sp. IIRAC-30 to suppress R. solani was elucidated. Furthermore, because lipopeptides active against phytopathogens generally show low toxicity to humans and the environment, the positive findings presented here suggest that the isolate IIRAC-30 could be a possible candidate for biocontrol of R. solani.

Dithiocarbazate complexes with the [M(PPh(3))](2+) (M=Pd or Pt) moiety Synthesis, characterization and anti-Tripanosoma cruzi activity

New neutral Pd(II) and Pt(II) complexes of the type [M(L)(PPh(3))] (M Pd or Pt) were prepared in crystalline form in high-yield synthesis with the S-benzyldithiocarbazates and S-4-nitrobenzyldithiocarbazates derivatives from 2-hydroxyacetophenone, H(2)L(1a) and H(2)L(1b), and benzoylacetone, H(2)L(2a) and H(2)L(2b). The new complexes [Pt(L(1a))(PPh(3))] (1), [Pd(L(1a))(PPh(3))] (2), [Pt(L(1b))(PPh(3))] (3), [Pd(L(1b))(PPh(3))] (4), [Pt(L(2a))(PPh(3))] (5), [Pd(L(2a))(PPh(3))] (6), [Pt(L(2b))(PPh(3))] (7) and [Pd(L(2b))(PPh(3))] (8) were characterized on the basis of elemental analysis, conductivity measurements, UV-visible, IR, electrospray ionization mass spectrometry (ESI-MS), NMR ((1)H and (31)P) and by X-ray diffraction studies. The studies showed that differently from what was observed for the H(2)L(1a) and H(2)L(1b) ligands, H(2)L(2a) and H(2)L(2b) assume cyclic forms as 5-hydroxypyrazolinic. Upon coordination, H2L2a and H2L2b suffer ring-opening reaction, coordinating in the same manner as H(2)L(1a) and H(2)L(1b), deprotonated and in O,N,S-tridentate mode to the (MPPh(3))(2+) moiety. All complexes show a quite similar planar fourfold environment around the M(II) center. Furthermore, these complexes exhibited biological activity on extra and intracellular forms of Trypanosoma cruzi in a time- and concentration-dependent manner with IC(50) values ranging from 7.8 to 18.7 mu M, while the ligand H(2)L(2a) presented a trypanocidal activity on trypomastigote form better than the standard drug benznidazole. (C) 2010 Elsevier Inc. All rights reserved.

Caracterização das vítimas de ferimentos por arma de fogo, atendidas pelo Serviço de Atendimento Móvel de Urgência em Campo Grande-MS

A violência, em todas as suas apresentações, tem crescido de forma avassaladora no país, elevando os indicadores de morbidade e mortalidade por causas externas. O uso das armas de fogo, muitas vezes, faz vítimas fatais ou que podem permanecer sequeladas. Tal fato tem aumentado o ônus do estado com internações hospitalares e acréscimo dos anos de vida perdidos da população jovem, que constitui a grande maioria dessas vítimas. Nesse sentido, o presente estudo objetivou fazer um levantamento das vítimas de ferimentos por arma de fogo, atendidas pelo Serviço de Atendimento Móvel de Urgência no município de Campo Grande-MS, no período de abril de 2005 a abril de 2007, nos dois primeiros anos de funcionamento, desde a implantação desse serviço na capital do Estado de Mato Grosso do Sul. Realizou-se estudo descritivo, baseado em análise documental do sistema de informação do SAMU do município de Campo Grande-MS. Foram descritos 233 atendimentos. Os resultados evidenciaram 213 vítimas do sexo masculino, a faixa etária mais acometida foi dos 20 aos 24 anos de idade, a cabeça e o pescoço foram as partes do corpo mais atingidas e a região Sul do município de Campo Grande foi a que concentrou maior número de atendimentos. Conclui-se que a violência por arma de fogo em Campo Grande-MS atinge a camada economicamente ativa da população e provém de regiões de bolsões de pobreza e desigualdade social, justificando a implantação de um serviço como o SAMU.

HPLC separation, NMR and QTOF/MS/MS structure elucidation of a prominent nitric oxide donor agent based on an isomeric composition of a nitrosyl ruthenium complex

A new and promising nitrosyl ruthenium complex, [Ru(NO)(bdqi-COOH)(terpy)](PF(6))(3), bdqi-COOH is 3,4-diiminebenzoic acid and terpy is 2,2`-terpyridine, has been synthesized as a NO donor agent. The procedure used for [Ru(NO)(bdqi-COOH)(terpy)](PF(6))(3) synthesis has, apparently, yielded the formation of two isomers in which the ligand bdqi-COOH appears to be coordinated in its reduced form (bdcat-COOH), which could have differences in their pharmacological properties. Therefore, it was intended to separate the two possible isomers by high-performance liquid chromatography (HPLC) and to characterize them by high resolution mass spectrometry (QTOF MS) and by magnetic nuclear resonance spectroscopy (NMR). The results obtained by MS showed that the ESI-MS mass spectra of both HPLC column fractions, e.g. peak 1 and peak 2, are essentially equal, showing that both isomers display nearly identical gas-phase behavior with clusters of isotopologue ions centered at m/z 573, m/z 543 and m/z 513. Regarding the NMR analysis, the results showed that the positional isomerism is located in the bdqi-COOH ligand. From the observed results it can be concluded that the synthesis procedure that has been used results in the formation of two [Ru(terpy)(bdqi-COOH)NO](PF(6))(3) isomers. (c) 2009 Elsevier B.V. All rights reserved.

Antimicrobial activity in the tick Rhipicephalus (Boophilus) microplus eggs: Cellular localization and temporal expression of microplusin during oogenesis and embryogenesis

Arthropods display different mechanisms to protect themselves against infections, among which antimicrobial peptides (AMPs) play an important role, acting directly against invader pathogens. We have detected several factors with inhibitory activity against Candida albicans and Micrococcus luteus on the surface and in homogenate of eggs of the tick Rhipicephalus (Boophilus) microplus. One of the anti-M. luteus factors of the egg homogenate was isolated to homogeneity. Analysis by electrospray mass spectrometry (ESI-MS) revealed that it corresponds to microplusin, an AMP previously isolated from the cell-free hemolymph of X (B.) microplus. Reverse transcription (RT) quantitative polymerase chain reactions (qPCR) showed that the levels of microplusin mRNA gradually increase along ovary development, reaching an impressive highest value three days after the adult females have dropped from the calf and start oviposition. Interestingly, the level of microplusin mRNA is very low in recently laid eggs. An enhance of microplusin gene expression in eggs is observed only nine days after the onset of oviposition, achieving the highest level just before the larva hatching, when the level of expression decreases once again. Fluorescence microscopy analysis using an anti-microplusin serum revealed that microplusin is present among yolk granules of oocytes as well as in the connecting tube of ovaries. These results, together to our previous data. suggest that microplusin may be involved not only in protection of adult female hemocele, but also in protection of the female reproductive tract and embryos, what points this AMP as a considerable target for development of new methods to control R. (B.) microplus as well as the vector-borne pathogens. (c) 2009 Elsevier Ltd. All rights reserved.

Simple method for determination of cocaine and main metabolites in urine by CE coupled to MS

in this work, a simple method for the simultaneous determination of cocaine (COC) and five COC metabolites (benzoylecgonine, cocaethylene (CET), anhydroecgonine, anhydroecgonine methyl ester and ecgonine methyl ester) in human urine using CE coupled to MS via electrospray ionization (CE-ESI-MS) was developed and validated. Formic acid at 1 mol/L concentration was used as electrolyte whereas formic acid at 0.05 mol/L concentration in 1:1 methanol:water composed the coaxial sheath liquid at the ESI nozzle. The developed method presented good linearity in the dynamic range from 250 ng/mL to 5000 ng/mL (coefficient of determination greater than 0.98 for all compounds). LODs (signal-to-noise ratio of 3) were 100 ng/mL for COC and CET and 250 ng/mL for the other studied metabolites whereas LOQ`s (signal-to-noise ratio of 10) were 250 ng/mL for COC and CET and 500 ng/mL for all other compounds. Intra-day precision and recovery tests estimated at three different concentration levels (500, 1500 and 5000 ng/mL) provided RSD lower than 10% (except anhydroecgonine, 18% RSD) and recoveries from 83-109% for all analytes. The method was successfully applied to real cases. For the positive urine samples, the presence of COC and its` metabolites was further confirmed by MS/MS experiments.

Mechanistic study of the addition reaction of TeCl(4) to alkynes: Participation of TeCl(3) centered-radical

The mechanism of the addition reaction of TeCl(4) to alkynes was indirectly established by the detection of TeCl(3) centered radicals using EPR spin trapping, ESI-MS and ESI-MS/MS characterization. Crown Copyright (C) 2008 Published by Elsevier B. V. All rights reserved.

The inducing NO-vasodilation by chemical reduction of coordinated nitrite ion in cis-[Ru(NO(2))L(bpy)(2)](+) complex

The synthesis of [Ru(NO(2)) L(bpy)(2)](+) (bpy = 2,2'-bipyridine and L = pyridine (py) and pyrazine (pz)) can be accomplished by addition of [Ru(NO) L(bpy) 2](PF(6))(3) to aqueous solutions of physiological pH. The electrochemical processes of [Ru(NO2) L(bpy) 2]+ in aqueous solution were studied by cyclic voltammetry and differential pulse voltammetry. The anodic scan shows a peak around 1.00 V vs. Ag/AgCl attributed to the oxidation process centered on the metal ion. However, in the cathodic scan a second peak around-0.60 V vs. Ag/AgCl was observed and attributed to the reduction process centered on the nitrite ligand. The controlled reduction potential electrolysis at-0.80 V vs. Ag/AgCl shows NO release characteristics as judged by NO measurement with a NO-sensor. This assumption was confirmed by ESI/MS(+) and spectroelectrochemical experiment where cis-[Ru(bpy)(2)L(H(2)O)](2+) was obtained as a product of the reduction of cis-[Ru(II)(NO(2)) L(bpy)(2)](+). The vasorelaxation observed in denuded aortic rings pre-contracted with 0.1 mu mol L(-1) phenylephrine responded with relaxation in the presence of cis-[RuII(NO2) L(bpy) 2]+. The potential of rat aorta cells to metabolize cis-[RuII(NO(2)) L(bpy)(2)](+) was also followed by confocal analysis. The obtained results suggest that NO release happens by reduction of cis-[RuII(NO(2)) L(bpy)(2)](+) inside the cell. The maximum vasorelaxation was achieved with 1 x 10(-5) mol L(-1) of cis-[RuII(NO(2)) L(bpy)(2)](+) complex.

Saxitoxins accumulation by freshwater tilapia (Oreochromis niloticus) for human consumption

The accumulation of saxitoxins (STXs) in fish from freshwater aquaculture was investigated for the first time in the present study. Cyanotoxins have been monitored in liver and muscle samples of Oreochromis miloticus by chromatographic methods, both before and after the deputation process. The results show that tilapia can accumulate STXs. Our findings suggest that deputation with clean water is an alternative process to eliminate STXs from fish and, therefore, improve the safety of tilapia for consumers. (C) 2009 Elsevier Ltd. All rights reserved.