[Sulfamic acid as a charring reagent in thin layer chromatography. II. An attempt to separate free bile acids and bile acid conjugates].
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Bile↗
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Determination of N-nitrosodimethylamine in nonfat dry milk: collaborative study.
Ten laboratories participated in a collaborative study of a method for the determination of N-nitrosodimethylamine (NDMA) in nonfat dry milk. NDMA is eluted with dichloromethane from a mixture of Celite, acidic sulfamic acid, and nonfat dry milk (all packed in a chromatography column), concentrated in a Kuderna -Danish concentrator, and finally analyzed by a GC-thermal energy analyzer technique. Ten samples were studied: 6 were naturally contaminated (NDMA levels 0.38-3.56 ppb) and 4 were spiked with known levels (0.96 and 3.2 ppb) of NDMA. The coefficients of variation (CV) of the complete data for the naturally contaminated samples (excluding the 2 samples containing the lowest levels) were 8.5% and 22.5% for repeatability and reproducibility, respectively. The corresponding CVs for the spiked samples were 14.4% and 20.4%, respectively. The percent recoveries of the added NDMA in the spiked samples (at the 2 levels indicated above) were 101.6 +/- 3.2 (omitting 1 outlier) and 95 +/- 2.1, respectively. The method has been adopted official first action.
Animals↗
Anomalous conductance in electrolyte solutions: a potentiometric and conductometric study of the dissociation of moderately strong acids
Properties of the associated forms of five moderately strong acids in aqueous solution (trichloro-, trifluoro-, chlorodifluoro-, and dichloroacetic acids) and sulfamic acid are studied by potentiometric and conductometric methods. Conductometric estimates of the acidity constants for the haloacetic acids are substantially different from the pH potentiometric values. However, the conductometric and pH potentiometric estimates of the acidity constants for sulfamic acid are in agreement. We interpret these results in terms of a neutral associated acid species of each of the haloacids which contributes to the electrolytic conductance.
Journal Article↗
Nitrosation of orally administered drugs under simulated stomach conditions.
Of a total of 61 drugs considered to be potentially nitrosatable on the basis of their chemical structure, 7 have indeed been nitrosated in gastric juice at pH 2 and under simulated human stomach conditions, where the pH was varied from about 7 to 2 within 60 min. The 7 nitrosatable drugs were ethambutole, despiramine hydrochloride, clomipramine hydrochloride, phenoxymethyl penicillin, aminophenazone, piperazine diadipate and analgine. Inhibition of nitrosation under simulated stomach conditions was also investigated using ascorbic acid, sulfanilamide, p-aminosalicylic acid and sulfamic acid. The first three agents were effective inhibitors, whereas sulfamic acid stimulated nitrosation within a distinct pH range.
Animals↗
Development of physicochemical nitrogen removal process for high strength industrial wastewater.
The biological nitrogen removal (BNR) process is the most common method for removing low quantities of ammonium from wastewater, but this method is not used for wastewater rich with ammonium. In this study, we have developed the physicochemical nitrogen removal process to remove the nitrogen content for a real industrial wastewater. The denitrification was accomplished by the physicochemical denitrification process using zinc powder and sulfamic acid in pH 2-4. The experimental parameters were examined by varying various reaction conditions such as pH, zinc feeding time, amount of sulfamic acid, and amount of nitrate concentration. For each experimental condition, the physicochemical denitrification process was determined by pH, amount of zinc powder and sulfamic acid, zinc feeding time and nitrate concentration.
Ammonia↗
Sulfamates and their therapeutic potential.
Starting from the very simple molecule sulfamic acid, O-substituted-, N-substituted-, or di-/tri-substituted sulfamates may be obtained, which show specific biological activities which were or started to be exploited for the design of many types of therapeutic agents. Among them, sulfamate inhibitors of aminoacyl-tRNA synthetases (aaRSs) were recently reported, constituting completely new classes of antibiotics, useful in the fight of drug-resistant infections. Anti-viral agents incorporating sulfamate moieties have also been obtained, with at least two types of such derivatives investigated: the nucleoside/nucleotide human immunodeficiency virus (HIV) reverse transcriptase inhibitors, and the HIV protease inhibitors (PIs). In the increasing armamentarium of anti-cancer drugs, the sulfamates occupy a special position, with at least two important targets evidenced so far: the steroid sulfatases (STSs) and the carbonic anhydrases (CAs). An impressing number of inhibitors of STSs of the sulfamate type have been reported in the last years, with several compounds, such as 667COUMATE among others, progressing to clinical trials for the treatment of hormone-dependent tumors (breast and prostate cancers). This field is rapidly evolving, with many types of new inhibitors being constantly reported and designed in such a way as to increase their anti-tumor properties, and decrease undesired features (for example, estrogenicity, a problem encountered with the first generation such inhibitors, such as EMATE). Among the many isozymes of CAs, at least two, CA IX and CA XII, are highly overexpressed in tumors, being generally absent in the normal tissues. Inhibition of tumor-associated CAs was hypothesized to lead to novel therapeutic approaches for the treatment of cancer. Many sulfamates act as very potent (low nanomolar) CA inhibitors. The X-ray crystal structure of the best-studied isozyme, CA II, with three sulfamates (sulfamic acid, topiramate, and EMATE) has recently been reported, which allowed for a rationale drug design of new inhibitors. Indeed, low nanomolar CA IX inhibitors of the sulfamate type have been reported, although such compounds also act as efficient inhibitors of isozymes CA I and II, which are not associated with tumors. A large number of anti-convulsant sulfamates have been described, with one such compound, topiramate, being widely used clinically as anti-epileptic drug. By taking into consideration a side effect of topiramate, an anti-epileptic drug leading to weight loss in some patients, it has recently been proposed to use this drug and related sulfamates for the treatment of obesity. The rationale of this use is based on the inhibition of the mitochondrial CA isozyme, CA V, involved in lipogenesis. Some sulfamates were also shown to possess potent inhibitory activity against acyl coenzyme A:cholesterol acyltransferase, an enzyme involved in cholesterol metabolism. One such agent, avasimibe, is in advanced clinical trials for the treatment of hyperlipidemia and atherosclerosis. Thus, the sulfamate moiety offers very attractive possibilities for the drug design of various pharmacological agents, which are on one hand due to the relative ease with which such compounds are synthesized, and on the other one, due to the fact that biological activity of most of them is impressive.
Amino Acyl-tRNA Synthetases↗
Major routes of metabolism of the food-borne carcinogen 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline in the rat.
The metabolic fate of 2-amino-3,8-dimethylimidazo[4,5-f] quinoxaline (MeIQx), a carcinogen formed in cooked meat and fish, has been investigated in male Sprague-Dawley rats. Five metabolites were recovered from bile of animals given an intragastric dose of [2-14C]MeIQx. These accounted for nearly all of the radioactivity in bile. The chemical structures of these metabolites were elucidated by proton NMR, UV and mass spectroscopy. Three structures may be assigned unambiguously: two sulfamates, N-(3,8-dimethylimidazo [4,5-f]quinoxalin-2-yl)sulfamic acid and N-(8-hydroxy-methyl-3-methylimidazo[4,5-f]quinoxalin-2-yl) sulfamic acid, and one glucuronide, N2-(beta-1-glucosiduronyl)-2-amino-3,8-dimethylimidazo[4,5-f ]quinoxaline. In addition, an acetyl and a glucosiduronyl conjugate of 5-hydroxy-MeIQx were observed. The spectral evidence did not allow an unambiguous assignment of the site of conjugation. The two glucuronides were excreted in urine and the sulfamate of MeIQx was found in feces as well as urine. All five metabolites were found to be non-mutagenic to Salmonella typhimurium TA98 with or without metabolic activation. The glucuronide conjugates were found also to be non-mutagenic when beta-glucuronidase was incorporated with S-9 mixture in the mutation assay, and thus all appear to be detoxification products. The previously reported metabolite, 2-amino-8-hydroxymethyl-3-methylimidazo[4,5-f]quinoxaline which is mutagenic to Salmonella typhimurium TA98 with metabolic activation, was identified as a minor component in both urine and feces.
Animals↗
Determination of total N-nitroso compounds and their precursors in frankfurters, fresh meat, dried salted fish, sauces, tobacco, and tobacco smoke particulates.
Total N-nitroso compounds (NOC) and NOC precursors (NOCP) were determined in extracts of food and tobacco products. Following Walters' method, NOC were decomposed to NO with refluxing HBr/HCl/HOAc/EtOAc and NO was measured by chemiluminescence. NOC were determined after sulfamic acid treatment to destroy nitrite, and NOCP were determined after treatment with 110 mM nitrite and then sulfamic acid. Analysis without HBr gave results < or =20% of those with HBr. This NOC method was efficient for nitrosamines but not nitrosoureas. The standard nitrosation for determining NOCP gave high yields for readily nitrosated amines, including 1-deoxy-1-fructosylvaline, but not for simple amines, dipeptides, and alkylureas. Mean NOC and NOCP results were (respectively, in micromol/kg of product) 5.5 and 2700 for frankfurters, 0.5 and 660 for fresh meat, 5.8 and 5800 for salted, dried fish, and 660 and 2900 for chewing tobacco (all for aqueous extracts) and 220 and 20000 nmol/cigarette for MeCN extracts of cigarette smoke filter pads.
Animals↗
New heterocyclic structures. thiazolo[3,2-a][1,2,5] thiadiazolo[3,4-d]pyrimidine and [1,2,5]thiadiazolo[3',4':4,5] pyrimido[2,1-b][1,3]thiazine. biological assays.
6,7-Dihydro-9H-thiazolo[3,2-a][1,2,5]thiadiazolo [3,4-d]pyrimidin-9-one, 7,8-dihydro-6H,10H-[1,2,5]thiadiazolo[3',4':4,5]pyrimido [2,1-b][1,3]thiazin-10-one and its 3-methyl derivative were prepared by reacting 6,7-diamino-2,3-dihydro-5H-thiazolo[3,2-a]pyrimidin-5-one, 7,8-diamino-3,4-dihydro-2H,6H-pyrimido[2,1-b][1,3]thiazin-6-one or its 3-methyl derivative with N-thionylaniline. A reaction mechanism is proposed. The compounds and the sodium salts of (7-amino-2,3-dihydro-5H-thiazolo[3,2-a]pyrimidin-5-on-6-yl)sulfamic acid, (8-amino-3,4-dihydro-2H,6H-pyrimido[2,1-b][1,3]thiazin-6-on-7-yl) sulfamic acid and its 3-methyl derivative were tested for antimicrobial and antimycotic activity on a number of strains, namely: E. Coli, Proteus mirabilis, P. vulgaris, Pseudomonas aeruginosa, Salmonella spp, Staphylococcus spp, Streptococcus faecalis, Bacillus subtilis, Sarcina lutea, Candida albicans, and for antiviral activity on Herpes simplex virus type 1 and Vescicular stomatitis virus. None of the compounds showed antiviral activity or exhibited biological activity against gram-negative, gram-positive bacteria or against mycetes.
Animals↗
Effect of additives on the flow-analysis determination of weak-acid-dissociable and total cyanide.
The effect of reductants, complexants, and nitrite eliminators on the flow-analysis determination of weak-acid-dissociable and total cyanide has been studied for: 1. cyanide recovery from copper, nickel, and iron complexes; 2. cyanide generation from the reagents in the presence of common interferents; and 3. cyanide consumption by the reagents in the presence of those interferents. In the absence of additives the UV-assisted recovery of (total) cyanide from the iron complexes (using a succinate buffer) was insufficient. Arsenite and hypophosphite had no measurable effect on the recovery, ascorbic acid resulted in total recovery but under these conditions nitrite and sulfite seemed to destroy cyanide. Phenanthroline promoted the recovery of cyanide from iron complexes but led to formation of cyanide from thiocyanate. Citrate resulted in good recovery but in the presence of nitrite cyanide was formed; the recovery with EDTA was also good. It proved necessary to destroy nitrite by use of sulfamic acid. If a combination of EDTA, citrate, and sulfamic acid is used rather high concentrations of thiocyanate, nitrite, thiosulfate, and sulfite can be tolerated in the samples. It is strongly advisable to test modifications of the cyanide determination comprehensively, because some surprising results have been obtained.
Acids↗
[Determination of alkali metals, ammonium ion and alkyl amines by non-suppressed ion chromatography].
The determination of Li+, Na+, NH4+, K+, CH3NH2, CH3CH2NH2 and CH3CH2CH2NH2 by non-suppressed ion chromatography using sulfamic acid as mobile phase is described. A cation-exchange column was employed for separation with conductivity detection. The effect of the eluent concentration on retention value was studied. The retention value of ions decreased with increasing the eluent concentration. The suitable eluent concentration was 4.0 mmol/L. When 4.0 mmol/L sulfamic acid was used as mobile phase, the detection limits (mg/L) for Li+, Na+, NH4+, K+, CH3NH2, CH3CH2NH2 and CH3CH2CH2NH2 were 0.008, 0.029, 0.027, 0.099, 0.069, 0.163 and 0.417 and the linear ranges of calibration curve(mg/L) were 0.008-20, 0.029-20, 0.027-20, 0.099-30, 0.069-30, 0.163-40 and 0.417-40, respectively. The method has been applied to the determination of tap water samples. The recoveries of added standard were 94.0%-97.6%.
Amines↗
Carbonic anhydrase inhibitors. Inhibition of the prokariotic beta and gamma-class enzymes from Archaea with sulfonamides.
A detailed inhibition study of carbonic anhydrases (CAs, EC 4.2.1.1) belonging to the beta- and gamma-families from Archaea with sulfonamides has been performed. Compounds included in this study were the clinically used sulfonamide CA inhibitors, such as acetazolamide, methazolamide, ethoxzolamide, topiramate, valdecoxib, celecoxib, dorzolamide, sulfanilamide, dichlorophanamide, as well as sulfanilamide analogs, halogenated sulfanilamides, and some 1,3-benzenedisulfonamide derivatives. The two gamma-CAs from Methanosarcina thermophila (Zn-Cam and Co-Cam) showed very different inhibitory properties with these compounds, as compared to the alpha-CA isozymes hCA I, II, and IX, and the beta-CA from Methanobacterium thermoautotrophicum (Cab). The best Zn-Cam inhibitors were sulfamic acid and acetazolamide, with inhibition constants in the range of 63-96 nM, whereas other investigated aromatic/heterocylic sulfonamides showed a rather levelled behavior, with KIs in the range of 0.12-1.70 microM. The best Co-Cam inhibitors were topiramate and p-aminoethyl-benzenesulfonamide, with KIs in the range of 0.12-0.13 microM, whereas the worst one was homosulfanilamide (KI of 8.50 microM). In the case of Cab, the inhibitory power of these compounds varied to a much larger extent, with sulfamic acid and sulfamide showing millimolar affinities (KIs in the range of 44-103 mM), whereas the best inhibitor was ethoxzolamide, with a KI of 5.35 microM. Most of these sulfonamides showed inhibition constants in the range of 12-100 microM against Cab. Thus, the three CA families investigated up to now possess a very diverse affinity for sulfonamides, the inhibitors with important medicinal, and environmental applications.
Archaea↗
Biological monitoring of workers exposed to 4,4'-methylene-bis-(2-orthochloroaniline) (MOCA). I. A new and easy determination of "free" and "total" MOCA in urine.
OBJECTIVE: The objective of the study was to validate a new and simple method to determine MOCA in the urine of exposed workers. METHODS: The separation, identification and quantification of urinary MOCA were performed in spiked urines by a sensitive and practical high-performance liquid chromatography (HPLC) method and applied to urine samples of 11 workers occupationally exposed to MOCA; the postshift urinary levels of MOCA in their urine samples with and without hydrolysis, "total" and "free" MOCA respectively, were determined. In addition, we investigated the use of citric or sulfamic acid as preservatives of urine samples. RESULTS: The "total" and "free" MOCA were extracted with isooctane from hydrolysed and nonhydrolysed 20-ml urine samples respectively. After evaporation, the residue was dissolved in 4 ml of 2.10(-2) M aqueous hydrochloric acid and analysed by an isocratic HPLC system using both ultraviolet (UV) detection at 244 nm and electrochemical detection working in oxidation mode (0.9 V) with an Ag/AgCl reference electrode. Mobile phase (50% acetonitrile in water containing 0.4% acetate buffer solution pH = 4.6) was used to complete the 20-min analysis. "Free" and "total" MOCA were chromatographed on a reversed-phase C8 column (5 microns, 250 mm x 4 mm). The standard curve of MOCA was linear over the range 5-500 micrograms/l in human urine. The detection limit was 1 microgram/l for a 20-microliter injection volume; the repeatability ranged from 5.6 to 1.3% (n = 6) for spiked urines at 5 and 500 micrograms/l, with a percentage recovery of 94 +/- 3%. The reproducibility of the method was 7.3% (n = 4) for spiked urine at 10 micrograms/l. The use of sulfamic acid as a preservative of urine samples is important to improve the precision and accuracy of the analysis. CONCLUSION: The results indicate that these analytical procedures using conventional apparatus may be used routinely and reliably with large numbers of urine samples for biological monitoring of the exposure to MOCA. The occupational exposure to MOCA in some factories in France is studied in the second part of this work.
Carcinogens↗
Sulfamate formation is a major route for detoxification of 2-amino-3-methylimidazo[4,5-f]quinoline in the rat.
The major biliary metabolite of 2-amino-3-methylimidazo[4,5-f]quinoline (IQ) in the rat was identified as the sulfamate derivative, N-[3-methylimidazo[4,5-f]quinolin-2-yl] sulfamic acid. Identification was accomplished primarily by u.v., 1H-n.m.r. and mass spectrometry of the material isolated from bile and confirmed by comparison with material synthesized by reaction of chlorosulfonic acid with IQ. The sulfamate was shown to be non-mutagenic in bacterial forward mutation assays. Greater than 20% of an administered dose of IQ could be recovered from feces (17%) and urine (5%) as the sulfamate. Very little unmetabolized IQ was recovered in bile, urine, or feces. Thus, the unusual process of N-sulfation is a major contributor to the detoxification and elimination of IQ in the rat.
Animals↗
Design and development of low cost, simple, rapid and safe, modified field kits for the visual detection and determination of arsenic in drinking water samples.
Arsenic is naturally found in surface and ground waters and the inorganic forms of arsenic are the most toxic forms. The adverse health effects of arsenic may involve the respiratory, gastrointestinal, cardiovascular, nervous, and haematopoietic systems. Arsenic contamination in drinking water is a global problem widely seen in Bangladesh and West Bengal of the Indian sub continent. As there is a great demand for field test kits due to the anticipated reduction of the US EPA arsenic standard from 50ppb to 10ppb a field kit which offers rapid, simple and safe method for precise estimation of arsenic at 10ppb in drinking water samples is developed. Field methods, based on the mercuric-bromide-stain, consist of three different major parts, which are carried out stepwise. The first part of the procedure is to remove serious interference caused by hydrogen sulphide. In commercially available kits either the sulphide is oxidized to sulphate and the excess oxidizing reagent removed prior to the hydride generation step or, the hydrogen sulphide is filtered out by passing the gas stream through a filter impregnated with lead acetate during the hydride generation step. The present method employs cupric chloride in combination with ferric chloride or Fentonis reagent for the removal of hydrogen sulphide, which is rapid, simple and more efficient. Other interferences at this step of the analyses are normally not expected for drinking water analysis. In the second step, the generation of the arsine gas involves the classical way of using zinc metal and hydrochloric acid, which produce the enascenti hydrogen, which is the actual reducing agent. Hydrochloric acid can be replaced by sulfamic acid, which is solid and avoids a major disadvantage of having to handle a corrosive liquid in the field. The arsine gas produces a yellowish spot on the reagent paper. Depending on the arsenic content, either, Yellow n H (HgBr)2 As (10-50ppb), Brown n (HgBr)3 As (50-100ppb) or Black n Hg3 As2 (>100ppb) are formed which can be precisely estimated by visual comparison with standard color chart. The results obtained by field kits agree well with the data obtained through I.C.P.AES methods. The most important characteristic for field measurement is that analytical results can be obtained on the site where the sample is taken with high precision and can be conveniently utilized for monitoring arsenic rapidly in a highly contaminated large geographical area.
Arsenic↗
Destruction of carcinogenic and mutagenic N-nitrosamides in laboratory wastes.
The chemical degradation of five N-nitrosamides used widely for the experimental induction of cancer has been studied with the goal of identifying, and experimentally validating, reliable methods that can be recommended for the destruction of carcinogenic N-nitrosoureas and related compounds in laboratory wastes. Although data are not yet complete, preliminary evidence indicates that none of the five methods studied thus far is ideal for hazard-control purposes. Decomposition with 1 mol/L potassium hydroxide solution destroyed the N-nitrosamides, but generated diazoalkanes, which are carcinogenic, toxic and potentially explosive. Treatment with strong acid in the presence of sulfamic acid or iron filings completely decomposed all N-nitrosamides without forming diazoalkanes, but failed in the presence of solvents which were immiscible with water. Cleavage with hydrogen bromide in glacial acetic acid proceeded to a point of maximum degradation, following which gradual reformation of the N-nitrosamide was observed; this resynthesis could be avoided by carefully bubbling nitrogen through the reaction mixture, but degradation was slow or failed completely in the presence of hydroxylic solvents. Permanganate oxidation was effective in sulfuric acid solution, but was incomplete when an alcohol or dimethyl sulfoxide was present. Salmonella typhimurium tester strains TA1535, TA1530 and TA100, which detect base-pair substitutions in DNA, detected mutagenic degradation products in each of the destruction methods, with the exception of the hydrobromic acid/acetic acid procedure.
Carcinogens↗
Effects of nitrosation on the formation of cyanide in publicly owned treatment works secondary effluent.
Cyanide has been detected in the effluents of some publicly owned treatment works (POTWs) at levels exceeding the influent concentration. The presence of nitrite ion (NO2-) as a common constituent in domestic wastewater effluents may play an important role in the formation of cyanide through reaction with certain kinds of organic compounds, especially aromatic compounds. Laboratory studies with seven organic compounds (aniline. p-toluidine, phenol, 1,2,4-trihydroxybenzene, L-serine, glycine, and benzoic acid) revealed that cyanide can be formed by reaction of nitrite with some of these compounds. The most substantial free cyanide (HCN. CN-) production observed at 25 degrees C was 0.15 mg/L from reaction of 0.01 mM 1.2.4-trihydroxybenze with 5 mg/L nitrite for 72 hours. Substantial free cyanide formation was also observed at pH 2-4 in experiments with POTW effluents when reactive organics and nitrite were both added to wastewater. Formation of cyanide through nitrosation was strongly pH dependent, being most significant at low pH (2 to 4) and negligible at neutral-to-high pH. This result points to nitrous acid (HNO2) as being more reactive than the dissociated NO2- ion. The reaction of these nitrite species with organics also occurs in conventional analyses for total cyanide which involve distillation under strongly acidic conditions. Sufficient sample pretreatment with sulfamic acid at the time of sampling, not at the time of analysis. is highly recommended to prevent biasing analytical measurement of total cyanide in POTW effluents.
Cyanides↗
Determination of ten N-nitrosoamino acids in cured meat products.
A rapid, sensitive, and accurate solid-phase extraction method was developed for the measurement of 10 N-nitrosoamino acids (NAAs) in cured meat products. In the procedure, the comminuted meat was mixed with sulfamic acid and Celite, and then added to a glass column containing anhydrous sodium sulfate. The column was washed with pentane, and the NAAs were eluted with ethyl acetate. The eluate was concentrated, then derivatized with diazomethane followed by acetic anhydride-pyridine reagent. The NAA methyl esters and their acylated hydroxy derivatives were separated by gas chromatography on a DB-5 fused silica capillary column and quantitated with a thermal energy analyzer, a chemiluminescence detector specific for nitric oxide derived from the thermal denitrosation of nitrosamines. Recovery of 10 of the NAAs exceeded 75% at the 10 ppb level. The method is applicable to a wide range of cured meat products.
Amino Acids↗