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PubMed1999

[A rapid separation and quantitation of sodium cyclamate in food by ion-pair reversed-phase high performance liquid chromatography].

A method of separation and quantitation of sodium cyclamate in foods by ion-pair reversed-phase high performance liquid chromatography is described. Sodium cyclamate can be separated on ODS column at room temperature by using a mobile phase of V(methanol):V(water, containing ion-pair reagent) = 30:70 at 1 mL/min flow rate. The effects of ion-pair reagent and methanol on the retention of sodium cyclamate were studied. The samples were quantified with an ultraviolet detector operated at 205 nm. The calibration curve was linear in the range of 0.50-2.50 g/L with a correlation coefficient of 0.9996. The recoveries were 96.9%-101.7%. The detection limit was 0.05 g/L. This method is simple, rapid and sensitive.

Calibration↗
PubMed1977

[Studies of the interractions of cyclamate with phenprocomon (author's transl)].

The effect of cyclamate on the anticoagulant activity of phenprocoumon was investigated in rats after single oral doses of phenprocoumon, cyclamate, or phenprocoumon/cyclamate. By means of high pressure liquid chromatrography [HPLC] the change of the concentration of phenprocoumon per unit time in sera was determined. The anticoagulant acitivity of phenprocoumon was determined by the extension of the prothromin-time (Quick-test). It was found that cyclamate gives rise to an elevated of phenprocoumon in the blood, and a reduction of the anticoagulanting potency.

4-Hydroxycoumarins↗
PubMed2002

Octahedral (cis-cyclam)iron(III) complexes with O,N-coordinated o-iminosemiquinonate(1-) pi radicals and o-imidophenolate(2-) anions.

Three octahedral complexes containing a (cis-cyclam)iron(III) moiety and an O,N-coordinated o-iminobenzosemiquinonate pi radical anion have been synthesized and characterized by X-ray crystallography at 100 K: [Fe(cis-cyclam)(L(1-3)(ISQ))](PF(6))(2) (1-3), where (L(1-3)(ISQ)) represents the monoanionic pi radicals derived from one-electron oxidations of the respective dianion of o-imidophenolate(2-), L(1), 2-imido-4,6-di-tert-butylphenolate(2-), L(2), and N-phenyl-2-imido-4,6-di-tert-butylphenolate(2-), L(3). Compounds 1-3 possess an S(t) = 0 ground state, which is attained via strong intramolecular antiferromagnetic exchange coupling between a low-spin central ferric ion (S(Fe) = 1/2) and an o-imino-benzosemiquinonate(1-) pi radical (S(rad) = 1/2). Zero-field Mössbauer spectra of 1-3 at 80 K confirm the low-spin ferric electron configuration: isomer shift delta = 0.26 mm s(-1) and quadrupole splitting DeltaE(Q) = 1.96 mm s(-1) for 1, 0.28 and 1.93 for 2, and 0.33 and 1.88 for 3. All three complexes undergo a reversible, one-electron reduction of the coordinated o-imino-benzosemiquinonate ligand, yielding an [Fe(III)(cis-cyclam)(L(1-3)(IP))](+) monocation. The monocations of 1 and 2 display very similar rhombic signals in the X-band EPR spectra (g = 2.15, 2.12, and 1.97), indicative of low-spin ferric species. In contast, the monocation of 3 contains a high-spin ferric center (S(Fe) = 5/2) as is deduced from its Mössbauer and EPR spectra.

Journal Article↗
PubMed2003

Thermically and electrochemically induced isomerization of a (bis(ferrocene)-cyclam)copper(II) complex.

The new bis(ferrocene)-cyclam macrocycle 1,8-bis(ferrocenylmethyl)-1,4,8,11-tetraazacyclotetradecane, denoted L, has been synthesized. Two Cu(II) complexes with L have been isolated and characterized from X-ray structure determination and electrochemical studies. These two LCu(II) complexes correspond to the type I (ferrocenyl subunits in the same side of the cyclam plane) and type III (ferrocenyl subunits above and below the cyclam plane) isomers. The type I LCu(II) complex was synthesized from L and a Cu(2+) salt, while the type III isomer was obtained by oxidation in air or by comproportionation of the Cu(I) complex. The interconversion between type I and type III LCu(II) complexes is negligible in acetonitrile and slow in dimethyl sulfoxide but fast via an electrochemical reduction-reoxidation cycle. According to UV-vis and electrochemical characterizations, the type III isomer is thermodynamically more stable and the type I isomer is kinetically favored. A type III LNi(II) complex was also isolated and characterized by X-ray diffraction analysis and from electrochemical studies.

Journal Article↗
PubMed2003

Synthesis and photophysical properties of new chromium(III) complexes of N-derivatized 1,4,8,11-tetraazacyclotetradecane ligands cis-[Cr(1,8-R(2)cyclam)Cl(2)]Cl, where R is a pendant chromophore. exclusive formation of the cis isomer.

Several new chromium(III) complexes have been synthesized utilizing derivatives of the macrocyclic ligand cyclam (1,4,8,11-tetraazacyclotetradecane) with various N-substituted chromophores in the 1 and 8 positions (1,8-R(2)cyclam) where R = CH(3), CH(2)Ph, CH(2)Nph (Nph = naphthyl), and CH(2)Anth (Anth = anthracyl). X-ray crystal structures were determined for all four complexes, and these are formed exclusively in the cis configuration with the two tertiary amines in the "hinge" positions (i.e., along the folding axis) of the coordinated ligand. As a result, the cis isomers appear to be inert to isomerization under conditions dramatically more forcing than needed to effect the cis to trans isomerization of the unsubstituted Cr(cyclam)Cl(2)(+) ion. Photophysical studies demonstrated that emission occurs solely from the metal-centered ligand field doublet excited states regardless of whether initial excitation is into the quartet ligand field bands or into the pi-pi bands of the pendant chromophore. Thus, excitation of the pendant chromophore results in efficient intramolecular energy transfer to the metal centered ligand field excited states.

Journal Article↗
PubMed2004

Proton-driven self-assembled systems based on cyclam-cored dendrimers and [Ru(bpy)(CN)4]2-.

1,4,8,11-tetraazacyclotetradecane (cyclam), which is one of the most extensively investigated ligands in coordination chemistry, in its protonated forms, can play the role of host toward cyanide metal complexes. We have investigated the acid-driven adducts formed in acetonitrile-dichloromethane (1:1 v/v) solution by [Ru(bpy)(CN)4](2-) with 1,4,8,11-tetrakis(naphthylmethyl)cyclam (1) and a dendrimer consisting of a cyclam core appended with 12 dimethoxybenzene and 16 naphthyl units (2). [Ru(bpy)(CN)4](2-), 1, and 2 exhibit characteristic absorption and emission bands, in distinct spectral regions, that are strongly affected by addition of acid. When a solution containing equimolar amounts of [Ru(bpy)(CN)4](2-) and 1 or 2 is titrated by trifluoroacetic acid, or when [Ru(bpy)(CN)4](2-) is titrated with (1.2H)2+ or (2.2H)2+, [[Ru(bpy)(CN)4](2-).(2H+).1] or [[Ru(bpy)(CN)4](2-).(2H+).2] adducts are formed in which the fluorescence of the naphthyl units is strongly quenched by very efficient energy transfer to the metal complex, as shown by the sensitized luminescence of the latter. The [[Ru(bpy)(CN)4]2-.(2H+).1] and [[Ru(bpy)(CN)4](2-).(2H+).2] adducts can be disrupted (i) by addition of a base (1,4-diazabicyclo[2.2.2]octane), yielding the starting species [Ru(bpy)(CN)4](2-) and 1 or 2, or (ii) by further addition of triflic acid, with formation of (1.2H)2+ or (2.2H)2+ and protonated forms of [Ru(bpy)(CN)4](2-). It is shown that upon stimulation with two chemical inputs (acid and base) both [[Ru(bpy)(CN)4](2-).(2H+).1] and [[Ru(bpy)(CN)4](2-).(2H+).2] exhibit two distinct optical outputs (a naphthalene-based and a Ru(bpy)-based emission) that behave according to an XOR and an XNOR logic, respectively.

Journal Article↗
PubMed1970

Production of mouse urinary bladder carcinomas by sodium cyclamate.

Sodium cyclamate was suspended in cholesterol pellets that were surgically implanted in the urinary bladders of mice. In duplicate experiments, incidences of mouse bladder carcinomas observed in animals exposed to these pellets were 78 and 61 percent compared with incidences of 13 and 12 percent in control mice exposed to pellets of pure cholesterol. The exposure of the mouse bladder to sodium cyclamate was very brief, as the time required for 50 percent of the compound to disappear from the pellets was about 1 hour. This experimental technique was found to be highly sensitive, reproducible, and predictive of the bladder carcinogenicity of orally administered cyclamate.

Animals↗
PubMed1970

Bladder tumors in rats fed cyclohexylamine or high doses of a mixture of cyclamate and saccharin.

Papillary transitional cell tumors were found in the urinary bladders in 8 rats out of 80 that received 2600 milligrams per kilogram of body weight per day of a mixture of sodium cyclamate and sodium saccharin (10:1) for up to 105 weeks. From week 79 on, several of these rats received cyclohexylamine hydrochloride (125 milligrams per kilogram per day, the molecular equivalent of the conversion of about 10 percent of the cyclamate dosage to cyclohexylamine) in addition to the sodium cyclamate and sodium saccharin. In another study in which 50 rats were fed daily 15 milligrams of cyclohexylamine sulfate per kilogram of body weight for 2 years, eight males and nine females survived. One of the eight males had a tumor of the urinary bladder. In neither study were bladder tumors found in the control rats or in rats treated with lower doses of the compounds.

Amines↗
PubMed1980

Complexing of Tc-99m with cyclam: concise communication.

The macrocyclic amine, cyclam, has been found to be an efficient complexing agent for Tc-99m. Complexes can be formed in yields of higher than 95% at pH 11 in 10(-3) M cyclam using 5 x 10(-6) M SnC4H4O6 as a reducing agent. The complex is positively charged and is stable in air. It is not decomposed by dilution, by 0.05 M NaOH, or 0.05 M H2O2, but does show slight decomposition in 0.05 M HCl. In unanesthetized mice the complex is cleared rapidly from the blood by the kidneys and liver. Preliminary studies show that derivatives of cyclam also complex Tc-99m.

Animals↗
PubMed1988

No evidence found for induction of dominant lethal mutations and heritable translocations in male mice by calcium cyclamate.

Calcium cyclamate, an artificial sweetener, was studied for its effectiveness in inducing transmissible chromosomal aberrations in germ cells of male mice. Both the dominant-lethal and the heritable translocation tests were carried out following daily treatment (on weekdays) of males by oral intubation with the maximum tolerated dose for 6 weeks. Calcium cyclamate is negative in both tests; therefore, there is no evidence of induced chromosome breakage and exchange.

Animals↗
PubMed1988

Intake of saccharin and cyclamate from Finnish foods between 1979 and 1985.

The dietary intake of saccharin and cyclamate was investigated during the period 1979-1985 in order to find out about the use as sweeteners in the food industry and hospitals and to obtain intake data for the toxicological evaluation of sweeteners in the Finnish diet. Eighty-nine samples of desserts served in 85 hospitals were analysed in 1983. Other samples investigated were artificially sweetened commercial foods available in Finland, such as soft drinks, sweets and jellies. The intake evaluation was carried out with reference to the acceptable daily intake (ADI), with commercial portions for a child being 20 kg and for an adult 60 kg. The most important foods with regard to the intake of saccharin and cyclamate were soft drinks. In 1979, 1982 and 1985, soft drinks contributed 128%, 93%, and 51%, respectively, of the ADI of artificial sweeteners for children and 42%, 31%, and 17% for adults. Artificially sweetened desserts served in hospitals contributed to 35% of the ADI for children and 11% for adults.

Cyclamates↗
PubMed1975

Gas chromatographic determination of micro-amounts of cyclamates.

It was found that triethylammonium cyclamate is converted into N-hepta-fluorobutyrylcyclohexylamine in a high and constant yield by reaction with hepta-fluorobutyric anhydride at 90 degrees for 1 h, and gas chromatography of the product gives a sharp peak that is highly sensitive to an electron capture detector. A useful method for the micro-determination of cyclamates was established by combining this reaction with gas chromatography.

Chromatography, Gas↗
PubMed2001

Selective continuous monitoring and analysis of mixtures of acesulfame-K, cyclamate, and saccharin in artificial sweetener tablets, diet soft drinks, yogurts, and wines using filter-supported bilayer lipid membranes.

This work describes a technique for the rapid and sensitive electrochemical flow injection monitoring and analysis of mixtures of the artificial sweeteners acesulfame-K, cyclamate, and saccharin using stabilized systems of filter-supported bilayer lipid membranes (BLMs). Injections of artificial sweeteners were made into flowing streams of a carrier electrolyte solution, and a transient current signal with duration of seconds reproducibly appeared in less than < 1 min after exposure of the lipid membranes to the artificial sweeteners. The magnitude of this signal was linearly related to the concentration of artificial sweeteners, which could be determined at micromolar levels. Repetitive cycles of injection of artificial sweeteners have shown no signal degradation during each cycle (30 sequential injections). The time of appearance of the transient response was different for each artificial sweetener and increased in the order of cyclamic acid, acesulfame-K, and saccharin. The difference in time of response has allowed selective detection and analysis of these artificial sweeteners in mixtures. The effect of potent interferences, including a wide range of compounds usually found in foods, proteins, and lipids was investigated. The results showed no interferences from these constituents of real food samples. The major interference from proteins (most common in lipid-film-based biosensors) can be eliminated by modulation of the carrier solution that does not allow adsorption of these compounds in BLMs. The technique was applied in real food samples, that is, in artificial sweetener tablets, diet soft drinks, wines, and yogurts that contain mixtures of these artificial sweeteners with aspartame and other compounds. A comparison of results using the present method and that of an Official Method of Analysis showed good agreement between the two methods.

Beverages↗
PubMed2004

Flow-injection determination of amine contaminants in cyclamate samples based on temperature for controlling selectivity.

This paper describes a flow-injection (FI) method for the simultaneous determination of aniline and cyclohexylamine impurities in cyclamate products. The method consists of the derivatization of amines with 1,2-naphthoquinone-4-sulfonate under selective and non-selective conditions. Here, the selectivity is achieved by working at 20 degree C, at which only aniline reacts, whilst higher temperatures (80 degree C) lead to a non-selective reaction of the two analytes. The FI manifold is composed of two flow cells for the spectrophotometric detection of derivatives at 480 nm. Experimental conditions have been optimized by factorial design and multicriteria making approach. Quantification is accomplished by differential analysis of the analyte contributions in the double peaks generated when the sample reaches cell 1 and cell 2. Results obtained with the proposed method are in satisfactory agreement with those provided by the standard method for the analysis of cyclamate samples.

Aniline Compounds↗
PubMed1975

Cyclamates: a review of the current position.

Cyclamates were prohibited for use as food additives in the U.S.A. and other parts of the world during 1970 because of the fears of carcinogenicity. The author reviews the evidence leading to this ban and discusses the appeal made against the decision which led to the lifting of the cyclamate restrictions in Australia in November 1974.

Animals↗
PubMed1976

Protective effects of cholestyramine in rats fed a low-fiber diet containing toxic doses of sodium cyclamate or amaranth.

Immature male rats were fed a purified, low-fiber diet containing massive doses of sodium cyclamate or amaranth (FD and C Red No. 2). Sodium cyclamate when incorporated at a 5% level in the purified, low-fiber diet resulted in toxic manifestations which were counteracted by the concurrent administration of the anion exchange resin cholestyramine at a 2 1/2% level in the diet. Other anion exchange resins were also active in this regard. Cholestyramine at a 2 1/2% level of supplementation was also active in counteracting the toxic effects induced by amaranth when the latter was incorporated at a 5% level in the purified, low-fiber diet.

Amaranth Dye↗