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PubMed1980

Intrarenal distribution of trimethoprim and sulfamethoxazole.

In the present study, rats were given trimethoprim (TMP, 10 mg/kg), sulfamethoxazole (SMZ, 50 mg/kg), or a combination of the respective doses of TMP and SMZ. Thirty-six rats received each of the drugs studied. Six recipients of a compound (or mixture) were evaluated hourly, from 1 to 6 h after intraperitoneal injection of the agent. At each timed interval, serum, urine, cortex, medulla, and papilla were analyzed for drug content. Peak serum values of 1.1 microgram of TMP and 131.1 microgram of active SMZ (nonacetylated sulfonamide) per ml were observed after injection of the combination TMP-SMZ. Although the cortical, medullary, and papillary TMP concentrations were severalfold higher than the respective serum values (P < 0.01), microbiologically active SMZ did not concentrate in the renal parenchyma and was found in lower concentration there than in the serum (P < 0.01). The levels of SMZ in all parts of the kidney of animals which received the mixture SMZ-TMP were lower than those detected in the animals which were given SMZ alone. The average ratio of active SMZ to TMP within the medulla and the papilla was less than 20 to 1 in the first 2 h. The intrarenal distribution of these drugs may have therapeutic implications.

Animals↗
PubMed1988

Contact allergy to colour developing agents in the guinea pig.

Colour developing agents, derivatives of p-phenylenediamine, can cause contact allergy. Patch test reactions to more than one colour developer are sometimes seen in patients. To study whether this is due to simultaneous sensitization or cross-reactivity, guinea pig maximization tests (GPMT) with CD-2, CD-3 and CD-4 were carried out. 5 experiments were performed, using pet. or water as vehicles. When pet. was used, the challenge concentrations could be raised and cross-reactivity between the colour developers, but not with p-phenylenediamine-dihydrochloride, was revealed. When water was used as vehicle, the challenge concentrations were limited because of staining of the test sites and irritation. CD-2, CD-3 and CD-4 were found to be extreme sensitizers according to the classification by Magnusson and Kligman. The importance of using an appropriate vehicle to obtain optimal conditions for the GPMT is stressed. To study the purity and stability of the chemicals used, analysis by HPLC of the test substances at different stages of the GPMT procedure was performed. Aqueous solutions of the colour developers were found to be unstable, while pet. mixtures were stable.

Animals↗
PubMed2006

Exhaustive extraction of sulfonamide antibiotics from aged agricultural soils using pressurized liquid extraction.

A pressurized liquid extraction (PLE) method was developed for the quantification of five sulfonamide antibiotics (sulfadiazine, sulfadimethoxine, sulfamethazine, sulfamethoxazole, and sulfathiazole) in aged soil samples. To account for sequestration effects the extraction was optimized using a composite grassland soil sample collected 11 days after the application of manure containing these substances. The optimized method uses a mixture of buffered water (pH 8.8) and acetonitrile (85:15) as solvent for the extraction at 200 degrees C and 100 bar during five min. The most important parameter for the extraction efficiency was temperature whereas the pH of the extraction solvent did hardly influence extraction efficiency between pH 4.1 and 8.8. A temperature increase from 100 to 200 degrees C improved the extraction efficiency up to a factor of six for aged residues in soils. In contrast, no temperature dependence was observed during short-term spike experiment. After 90 min exposure in these spike experiments we recovered 62-93% of the sulfonamides, except for sulfamethoxazole with only 41%. These percentages decreased substantially after a contact time of 6 and 17 days. The reasons for this decline remained unknown. Inter-day precision of the method was very satisfactory: relative standard deviations from the average were below 10%. Limits of detection for the extraction procedure were lower than 15 microg/kg. The performance of the developed extraction method was demonstrated by measuring the decrease of sulfonamide concentration in a top soil after manure application. Within 3 months the concentration of sulfadiazine dropped from 450 to 150 microg/kg.

Anti-Bacterial Agents↗
PubMedDate not supplied

Characterization of sulfonamides by flow injection and liquid chromatography-electrospray ionization-mass spectrometry after online photoderivatization.

The online photochemical identification of six sulfa compounds, sulfadiazine, sulfamerazine, sulfamethoxazole, sulfaisoxazole (SIX), sulfamoxole (SMX), and sulfamethizole, are investigated using flow injection and liquid chromatography (LC)-electrospray ionization-mass spectrometry (MS). Although the identification of some of the mentioned sulfonamides can be performed by recognizing their respected protonated molecules, more positive MS identification of many of these compounds is possible because they undergo various phototransformation processes to produce different product profiles. The LC separation and online photolysis of a mixture containing the geometric isomers SIX and SMX is such an example. With no photolysis, the MS spectra for SIX and SMX are virtually identical, showing primarily the sodiated molecule at m/z 290 with a relative abundance of 100% in addition to a few small peaks caused by fragments. With photolysis, SMX is found to form multiple major ions from 100 to 241 amu. However, SIX follows a similar fragmentation pathway either with or without photolysis. Online photochemistry should be a viable approach to extend the capabilities of LC instruments interfaced to a single quadrupole MS detector.

Chromatography, Liquid↗
PubMed2007

Allosteric tuning of the intra-cavity binding properties of a calix[6]arene through external binding to a ZnII center coordinated to amino side chains.

Molecular recognition by calix[6]arene-based receptors bearing three primary alkylamino side chain arms (1) is described. Complexation of Zn(II) ion provides the dinuclear mu-hydroxo complex 2G(OH), XRD characterization of which, together with solution studies, provided evidence of its hosting of neutral polar organic guests G. Treatment of this complex with a carboxylic acid or a sulfonamide (XH) results in the formation of mononuclear species 3G(X), one of which (X = Cl) has been characterized by XRD. A dicationic complex 3G(RNH2) is obtained upon treatment of 2G(OH) with a mixture of an alkylamine and a strong acid. Each of these Zn(II) complexes features a tetrahedral metal ion bound to the three amino arms of ligand 1 and to an exogenous ligand (either HO-, X-, or RNH2) sitting outside of the cavity. As a result, the metal ion structures the calixarene core, constraining it in a cone conformation suitable for guest hosting. The receptor properties of these compounds have been explored in detail and are compared with those of the trisammonium receptor 1G(3H+), based on the same calixarene core, as well as those of the trisimidazole-based dicationic Zn funnel complexes. This study reveals very different host properties, in spite of the common hydrophobic, pi-basic, and hydrogen-bonding acceptor properties of the calixarene cores. A harder external ligand produces a less polarized receptor that is consequently particularly sensitive to the hydrogen-bonding ability of its guest. The less electron-rich the apical ligand, and a fortiori the trisammonium host, the more sensitive the receptor to the dipole moment of the guest. All this stands in contrast with the funnel Zn complexes, in which the coordination link plays a dominant role. It is also shown that the asymmetry of an exo-coordinated enantiopure amino ligand is sensed by the guest. This supramolecular system nicely illustrates how the receptor properties of a hydrophobic cavity can be allosterically tuned by the environment.

Binding Sites↗
PubMed2006

Water remediation by micelle-clay system: case study for tetracycline and sulfonamide antibiotics.

Removal of tetracycline and sulfonamide antibiotics from water by micelles pre-adsorbed on montmorillonite was studied. Micelles of benzyldimethylhexadecylammonium (BDMHDA) were used. Batch experiments demonstrated that the micelle-clay complexes (1% w/w) removed 96-99.9% of antibiotics from their water solutions containing from 5 to 50 mg/L of pharmaceuticals. Column filters (25 cm) made of a mixture of quartz sand and BDMHDA micelle-clay complex at 100:1 w/w ratio removed 94-99.9% of above pharmaceuticals from initial solutions containing 10mg/L and 89% of sulfamethizole from an initial solution containing 10 microg/L of this antibiotic. These filters were also very efficient in the removal of antibiotics in the presence of dissolved soil organic matter removing 89-99% of tetracycline and sulfamethizol from initial solutions containing 10 mg/L of antibiotic in the presence of 8 mg/L of humic acid, or 9 mg/L of fulvic acid. These data indicate that micelle-clay complexes are very efficient for water purification from tetracycline and sulfonamide antibiotics.

Aluminum Silicates↗
PubMedDate not supplied

Simultaneous determination of binary mixtures of sulfonylurea herbicides in water by first-derivative photochemically induced spectrofluorimetry.

First-derivative photochemically induced spectrofluorimetry (PIF-1D) is applied to the simultaneous determination of binary mixtures of 4 sulfonylurea herbicides in aqueous micellar samples. Synthetic binary mixtures of sulfometuronmethyl with chlorsulfuron, metsulfuron-methyl, and 3-rimsulfuron, respectively, are well resolved by using the zero-crossing point procedure. PIF-1D allows the determination of binary mixtures of these herbicides with linear dynamic ranges over about 2 orders of magnitude, limits of detection between 0.5 and 52 ng/mL, and relative standard deviations within 0.3-2.9%. Application to the determination of binary mixtures of these herbicides in spiked tap water samples yielded satisfactory recoveries (90-117%).

Arylsulfonates↗
PubMed2001

Determination of ebrotidine metabolites in overlapping peaks from capillary zone electrophoresis using chemometric methods.

This paper illustrates the possibilities of chemometric methods in the resolution and quantification of various compounds in overlapping peaks from capillary electrophoresis. Ebrotidine and most of its metabolites were efficiently separated by capillary zone electrophoresis (CZE) in a fused-silica capillary. However, the procedure was not suitable for the physical separation of the three less ionizable metabolites, which comigrated and overlapped with the electroosmotic flow signal. Multivariate curve resolution based on an alternating least squares procedure was used for their mathematical resolution. For such a purpose, data obtained in the CZE system with a diode array detector, which consisted of UV spectra registered over time, were analyzed. The ebrotidine metabolites were successfully resolved and quantified in synthetic mixtures and urine samples.

Benzenesulfonates↗
PubMed2002

Amplification of screening sensitivity through selective destruction: theory and screening of a library of carbonic anhydrase inhibitors.

A new method for identifying enzyme inhibitors is to conduct their synthesis in the presence of the targeted enzyme. Good inhibitors form in larger amounts than poorer ones because the binding either speeds up synthesis (target-accelerated synthesis) or shifts the synthesis equilibrium (dynamic combinatorial libraries). Several groups have successfully demonstrated this approach with simple systems, but application to larger libraries is challenging because of the need to accurately measure the amount of each inhibitor. In this report, we dramatically simplify this analysis by adding a reaction that destroys the unbound inhibitors. This works similar to a kinetic resolution, with the best inhibitor being the last one remaining. We demonstrate this method for a static library of several sulfonamide inhibitors of carbonic anhydrase. Four sulfonamide-containing dipeptides, EtOC-Phe(sa)-Phe (4a), EtOC-Phe(sa)-Gly (4b), EtOC-Phe(sa)-Leu (4c) and EtOC-Phe(sa)-Pro (4d), were prepared and their inhibition constants measured. These inhibitors migrated to the carbonic anhydrase compartment of a two-compartment vessel. Although higher concentrations of the better inhibitors were observed in the carbonic anhydrase compartment, the concentration differences were small (1.83:1.71:1.54:1.46:1 for 4a:4b:4c:4d:5, where 5 is a noninhibiting dipeptide EtOC-Phe-Phe). Addition of a protease rapidly cleaved the weaker inhibitors (4d and 5). Intermediate inhibitor 4c was cleaved at a slower rate, and at the end of the reaction, only 4a and 4b remained. In a separate experiment, the ratio of 4a to 4b was found to increase over time to a final ratio of nearly 4:1. This is greater than the ratio of their inhibition constants (approximately 2:1). The theoretical model predicts that these ratios would increase even further as the destruction proceeds. This removal of poorer inhibitors simplifies identification of the best inhibitor in a complex mixture.

Binding, Competitive↗
PubMed2005

Cyclo-oxygenase-2, endothelium and aortic reactivity during deoxycorticosterone acetate salt-induced hypertension.

OBJECTIVE: To test the hypothesis that the enhanced vascular responsiveness to norepinephrine that occurs during deoxycorticosterone acetate (DOCA)-salt induced hypertension is causally related to increased expression of cyclo-oxygenase (COX)-2 and oxidative stress, which diminishes the vasomodulatory influence of endothelium-derived nitric oxide. METHODS: Four groups of age-matched, male Sprague-Dawley rats were studied: Sham (normotensive); DOCA-salt (hypertensive); DOCA-salt treated with manganese(III) tetra(4-benzoic acid) porphyrin chloride [MnTBAP, an antioxidant; 15 mg/kg intraperitoneally (i.p.) for 21 days]; DOCA-salt treated with {N-[2-(cyclohexyloxy)-4-nitrophenyl]-methane sulfonamide} (NS-398, a COX-2 selective blocker; 5 mg/kg i.p. for 7 days). Contraction and relaxation were measured with FT03 force transducers coupled to a Grass polygraph in aortic rings bathed with physiologic salt solution (37 degrees C) and bubbled with a 5%CO2/95%O2 gas mixture. Aortic sensitivities (pD2 values) to norepinephrine and serum isoprostanes (8-iso-prostaglandin F2alpha, a marker of oxidative stress) were measured for each experimental paradigm. RESULTS: NS-398 significantly reduced maximal contractions in response to norepinephrine in aortic rings from Sham (44 +/- 3%) and DOCA-salt (96 +/- 2%) group rats. Expression of COX-2 protein increased significantly in vessels from DOCA-salt rats compared with those from Sham group rats. Treatment of DOCA-salt rats with either MnTBAP or NS-398 alleviated hypertension, normalized aortic pD2 values for norepinephrine and restored serum 8-isoprostane concentrations towards those observed in Sham group rats. CONCLUSIONS: COX-2 expression increases during DOCA-salt hypertension, and mediates production of factors that enhance rat aortic contractility in response to norepinephrine. Our data also suggest a role for increased oxidative stress, which is at least in part dependent on enhanced COX-2 expression, in the mechanism(s) of enhanced aortic contractility in response to norepinephrine during DOCA-salt hypertension.

Animals↗
PubMed1983

Acute toxicity of some silver salts of sulfonamides in mice and the efficacy of penicillamine in silver.

The silver salt of 2-metanilamido-5-chloropyrimidine (AgMCP) and the sodium, amminosilver and trimethylphosphite-silver salts of 3',5'-dichlorobenzenesulfonanilide (NaDBS, AgNH3DBS and AgP(OCH3)3DBS were synthesized as possible antibiotic of antiparasitic drugs. All the organosilver compounds were extremely water-insoluble. For animal studies these, and other reference compounds, were given as fine suspensions in an Emulphor-safflower oil mixture. The ip LD50's in mice in mmol/kg were: 1.67 for NaDBS, 0.22 for silver acetate (AgAc), 0.15 for AgP(OCH3)3DBS, 0.13 for AgMCP and 0.10 for AgNH3DBS. When given by mouth, 15 mmol AgAc/kg produced a high mortality, but none of the organosilver compounds caused death in maximal doses (1.9 to 2.6 mmol/kg) that could be given based on considerations of total volume and stability of the suspension. All the silver compounds, including AgAc, produced a similar toxic syndrome with initial hyperexcitability, ataxia, central nervous depression, labored breathing, loss of righting reflex and death. Most deaths occurred between 12 and 24 hours after dosing. In contrast, animals given NaDBS often died within 3 hours although the major signs were very similar to those produced by the silver compounds. When given ip as a single dose 30 minutes after AgAc, D-penicillamine was effective in reducing mortality, but it had no effect on the mortality of the organosilver compounds. Histological studies revealed similar patterns of silver deposition, especially in the liver and kidneys, at 6, 18 and 24 hours after the organosilver compounds and after AgAc. We conclude that the presence of silver contributes significantly to the acute toxicity of these sulfonamides although they may dissociate free silver less readily than does AgAc.

Animals↗
PubMed2006

Multi-component analysis of tetracyclines, sulfonamides and tylosin in swine manure by liquid chromatography-tandem mass spectrometry.

A multi-component method focussing on thorough sample preparation has been developed for simultaneous analysis of swine manure for three classes of antibiotic-tetracyclines, sulfonamides, and tylosin. Liquid manure was initially freeze-dried and homogenised by pulverization before extraction by pressurised liquid extraction. The extraction was performed at 75 degrees C and 2,500 psig in three steps using two cycles with 0.2 mol L(-1) citric acid buffer (pH 4.7) and one cycle with a mixture of 80% methanol with 0.2 mol L(-1) citric acid (pH 3). After liquid-liquid extraction with heptane to remove lipids, the pH of the manure was adjusted to 3 with formic acid and the sample was vacuum-filtered through 0.6 mum glass-fibre filters. Finally the samples were pre-concentrated by tandem SPE (SAX-HLB). Recoveries were determined for manure samples spiked at three concentrations (50-5,000 microg kg(-1) dry matter); quantification was achieved by matrix-matched calibration. Recoveries were >70% except for oxytetracycline (42-54%), sulfadiazine (59-73%), and tylosin (9-35%) and did not vary with concentration or from day-to-day. Limits of quantification (LOQ) for all compounds, determined as a signal-to-noise ratio of 10, were in the range 10-100 microg kg(-1) dry matter. The suitability of the method was assessed by analysis of swine manure samples from six different pig-production sites, e.g. finishing pigs, sows, or mixed production. Residues of antibiotics were detected in all samples. The largest amounts were found for tetracyclines (up to 30 mg kg(-1) dry matter for the sum of CTC and ECTC). Sulfonamides were detected at concentrations up to 2 mg kg(-1) dry matter (SDZ); tylosin was not detected in any samples.

Animals↗