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PubMedDate not supplied

[Determination of epsilon-caprolactam in food media by thin-layer chromatography].

The method for thin-layer chromatography has been developed for determination of epsilon-caprolactam in food media: fats, dry products. The method sensitivity is 0.01 mg/kg (mg/1) for fats and 0,005 mg/kg for dry products. The method error is 20%. epsilon-Caprolactam was extracted from fats by water, from dry products by ethyl alcohol. The extracts were evaporated and chromatographed in a thin layer of silica gel. epsilon-Caprolactam was determined on the plates from the spot area. The method was used for hygienic evaluation of polyamide-6 film intended for packing fats and dry products.

Azepines↗
PubMed2005

Design of a "green" one-step catalytic production of epsilon-caprolactam (precursor of nylon-6).

The ever-increasing industrial demand for nylon-6 (polycaprolactam) necessitates the development of environmentally benign methods of producing its precursor, epsilon-caprolactam, from cyclohexanone. It is currently manufactured in two popular double-step processes, each of which uses highly aggressive reagents, and each generates substantial quantities of largely unwanted ammonium sulfate as by-product. Here we describe a viable laboratory-scale, single-step, solvent-free process of producing epsilon-caprolactam using a family of designed bifunctional, heterogeneous, nanoporous catalysts containing isolated acidic and redox sites, which smoothly convert cyclohexanone to epsilon-caprolactam with selectivities in the range 65-78% in air and ammonia at 80 degrees C. The catalysts are microporous (pore diameter 7.3 A) aluminophosphates in which small fractions of the Al(III)O4(5-) and P(V)O4(3-) tetrahedra constituting the 4-connected open framework are replaced by Co(III)PO4(5-) and Si(IV)O4(4-) tetrahedra, which become the loci of the redox and acidic centers, respectively. The catalysts may be further optimized, and already may be so designed as to generate selectivities of approximately 80% for the intermediate oxime, formed from NH2OH, which is produced in situ within the pore system. The advantages of such designed heterogeneous catalysts, and their application to a range of other chemical conversions, are also adumbrated.

Journal Article↗
PubMed2002

Tetraaqua-1kappa4O-bis(epsilon -caprolactam-1kappa O)-mu-cyano-1:2kappa 2N:C-pentacyano-2kappa 5C-iron(III)yttrium(III), a novel cyano-bridged dinuclear complex.

Using caprolactam as a ligand, the novel title cyano-bridged yttrium(III)-ferricyanide complex, [Y(caprolactam)(2)(H(2)O)(4)Fe(CN)(6)] or [FeY(CN)(6)(C(6)H(11)NO)(2)(H(2)O)(4)], has been synthesized and structurally characterized. The Y atom is seven-coordinate and has approximately pentagonal-bipyramidal stereochemistry, with water molecules occupying apical positions. Of the five ligands in equatorial positions, one is the N-bound bridging cyano group, and flanking this are two O-bound caprolactam moieties, which are markedly inclined towards the bridged ferricyanide moiety such that they partially envelop it. Water molecules occupy the remaining two equatorial positions. The Y-N-C-Fe-C-N sequence of atoms lies on a crystallographic twofold axis and is therefore perfectly linear, which has not been observed previously in cyano-bridged bimetallic complexes.

Journal Article↗
PubMed1982

Carcinogenesis Bioassay of Caprolactam (CAS No. 105-60-2) in F344 Rats and B6C3F1 Mice (Feed Study).

A carcinogenesis bioassay of caprolactam, a chemical intermediate used in the production of nylon 6, was conducted by feeding diets containing 3,750 or 7,500 ppm caprolactam to groups of 50 male or female F344 rats and 7,500 or 15,000 ppm to groups of 50 male or female B6C3F1 mice for 103 weeks. Control groups consisted of 50 undosed rats and 50 undosed mice of each sex. Throughout the bioassay, mean body weight gains for dosed rats and mice of either sex were decreased when compared with those of the controls. No other compound-related effects were observed. Under the conditions of this bioassay, caprolactam was not carcinogenic for F344 rats or B6C3F1 mice. Levels of Evidence of Carcinogenicity: Male Rats: Negative Female Rats: Negative Male Mice: Negative Female Mice: Negative Synonyms: aminocaproic lactam; 2-oxohexamethylenimine

Journal Article↗
PubMed1988

Three-generation reproduction study with caprolactam in rats.

In a three-generation reproduction study, rats were given caprolactam in the diet of 0, 1000, 5000 and 10,000 ppm. No treatment-related effects were observed in the parental animals with respect to mortality, clinical signs, reproductive performance or gross pathology findings. Consistently lower body weights were noted in the P2 and P3 mid- and high-dose males and females. Consistently lower mean food consumption values were noted in the P2 and P3 mid- and high-dose males and the high-dose females. These differences were generally significant (P less than or equal to 0.05) in the high-dose group of both sexes. Compound-related histopathologic findings noted in the high-dose P1 males consisted of a slight increase in the severity of spontaneous nephropathies, occasionally accompanied by granular casts. The offspring data revealed no treatment-related effect with respect to gross appearance, gross pathology, survival, number of pups, percentage of male pups or kidney weight. Analysis of the offspring body weights on Days 1, 7 and 21 of lactation revealed consistently and generally significant lower mean values in the high-dose male and female animals of all filial generations. The mean body weights of both sexes in the mid-dose group were generally lower than those of the controls. The effects on mean body weight, mean food consumption and the group increases in the severity of nephropathy, accompanied by the presence of granular casts in some animals, are considered to be related to the administration of caprolactam.

Animals↗
PubMed1989

Chromosomal damage induced by caprolactam in human lymphocytes.

Caprolactam was tested in the in vitro human lymphocyte cytogenetic assay both in the presence and absence of S9 mix at dose levels up to 5500 micrograms/ml using lymphocytes obtained from a male donor and in the presence of S9 mix using lymphocytes obtained from a female donor. Statistically significant increases in chromosomal damage were observed at 5500 micrograms/ml dose level in cells from both donors. This positive response was enhanced by the inclusion of chromosomal gaps in the calculations. It was concluded that caprolactam induces chromosomal damage in human lymphocytes in vitro albeit at comparatively high dose levels.

Azepines↗
PubMed1989

Chromosomal analyses of human lymphocytes exposed in vitro to caprolactam.

Caprolactam was tested for the induction of chromosomal aberrations in cultured human lymphocytes from one male donor and one female donor. At 7.5 mg/ml, caprolactam-treated cells from the male showed a small but significant increase in the frequency of aberrations. No effect was observed in cells from the female if gaps are excluded.

Adult↗
PubMed1989

An evaluation of caprolactam and benzoin in the mouse micronucleus test.

Caprolactam (CAP) and benzoin (ZOIN) were tested in the mouse micronucleus test at two dose levels, one of which was the maximum tolerated dose. The compounds were administered by the oral route to groups of 5 male and 5 female mice. No statistical significant increase over control values of the frequency of PCE-containing micronuclei was observed at any dose level or sampling time, with the exception of CAP at a dose level of 700 mg/kg at the 24-h sampling time, where a small statistically significant effect was observed both when the sexes were analysed combined and separately. Due to this observation a limited repeat was carried out on CAP at the 700 mg/kg dose level at the 24-h sampling time. In the repeat study similar trends were observed even following the analysis of 5000 cells per animal. However, when these data were compared with historical control data no such effects were observed, the effects were therefore considered to be of questionable validity. Throughout the study the positive control (cyclophosphamide) gave an elevated biologically and statistically significant increase at all sampling times, thus verifying the sensitivity of the test system. It was therefore concluded that caprolactam and benzoin are not clastogenic in the mouse micronucleus test.

Animals↗
PubMed1989

DNA damage in mouse and rat liver by caprolactam and benzoin, evaluated with three different methods.

Benzoin and caprolactam were examined for their capability of inducing alkaline DNA fragmentation in mouse and rat liver DNA after treatment in vivo. Three different methods were used. With the alkaline elution technique we measured an effect presumably related to the conformation of the DNA coil. With a viscometric and a fluorometric unwinding method we measured an effect presumably related to the number of unwinding points in DNA. For both compounds only the alkaline elution technique was clearly positive. The results suggest that both caprolactam and benzoin can induce an important change in the conformation of the DNA coil without inducing true breaks in DNA.

Animals↗
PubMed1984

The distribution of [14C]caprolactam in male, female and pregnant mice.

The distribution of [14C]caprolactam was studied by whole-body autoradiography in male, female and 14.5-day-pregnant mice. This technique does not allow translocation or removal of soluble compounds from the sites of localization. Pregnant mice were frozen 20 min and 1, 3, 9 and 24 hr after oral administration of the compound. The non-pregnant mouse was frozen 3 hr after oral dosing; two male mice were frozen 20 min and 9 hr after intravenous administration. Radioactivity was rapidly absorbed from the stomach and distributed throughout the entire animal, including the foetuses. There was efficient elimination by the kidney and liver. Material secreted by the liver into bile and intestinal contents appeared not to be reabsorbed via the enterohepatic circulation. The kinetics of distribution and elimination appeared to be the same in male, female and pregnant animals. The only sites of retention of radioactivity after 24 hr were the umbilical cords, amnion, yolk sac, maternal lens, maternal Harderian gland and maternal liver. The distribution into and removal from the foetuses was typical of molecules that diffuse freely across the placenta. There was no retention of radioactivity in any foetal tissue. With the possible exception of some residual activity in the nasal epithelium, no localization was seen that would suggest a site of toxic action of caprolactam.

Animals↗
PubMed1992

Identification of caprolactam as a potential contaminant in parenteral solutions stored in overwrapped PVC bags.

Semipreparative liquid chromatographic separation and subsequent off-line mass spectrometry have revealed caprolactam as a new contaminant in intravenous solutions. The content of the lactam was found to be 1.2-15.0 mg l-1 determined by liquid chromatography. Contamination is attributed to migration of caprolactam from the protecting plastic envelope through the PVC barrier and into the intravenous solution. Migration occurs during the final heat sterilization process.

Caprolactam↗
PubMed2006

Synthesis and evaluation of unsaturated caprolactams as interleukin-1beta converting enzyme (ICE) inhibitors.

Peptidomimetic compounds possessing a caprolactam ring constraint were prepared and evaluated as interleukin-1beta converting enzyme (ICE) inhibitors. The caprolactam ring was used to constrain the P3 region of our inhibitors. This strategy proved to be effective for the synthesis of ICE inhibitors, maintaining key hydrogen bond interactions with the enzyme and invoking a preferred conformation for binding. Several compounds exhibited IC(50) values less than 10nM in a caspase-1 enzyme assay and less than 100nM in a THP-1 whole cell assay measuring IL-1beta production. Two compounds, 13c and 13j, were found to have good oral bioavailability (>50%) in rats when administered as prodrugs.

Animals↗
PubMed2003

Design, synthesis, and development of novel caprolactam anticonvulsants.

Epilepsy afflicts 1-2% of the world's population and often goes untreated; nearly 70% of those with a form of epilepsy fail to receive proper treatment. Therefore, there is great demand for the design of novel, effective anticonvulsants to combat epilepsy in its numerous forms. Previously, alpha-hydroxy-alpha-phenylcaprolactam was found to have rather potent antiepileptic activity [anti-maximal electroshock (MES) ED(50)=63 mg/kg and anti-subcutaneous Metrazol (scMet) ED(50)=74 mg/kg] when administered intraperitoneally in mice. We focused our attention on the development of this compound through traditional medicinal chemistry techniques-including the Topliss approach, isosteric replacement, methylene insertion, and rigid analogue approach-in the hopes of determining the effect of caprolactam alpha-substitution and other structural modifications on anticonvulsant activity. A number of the desired targets were successfully synthesized and submitted to the Anticonvulsant Screening Program of the National Institute of Neurological Disorders and Stroke (NINDS). Phase I results were quite promising for at least three of the compounds: alpha-ethynyl-alpha-hydroxycaprolactam (10), alpha-benzyl-alpha-hydroxycaprolactam (11), and alpha-hydroxy-alpha-(phenylethynyl)caprolactam (13). Phase II results for 11 strongly suggested it as a new structural class for further development, as it exhibited an anti-MES T.I. in excess of 4.0. Further, the potent activity of 13 in all models also pointed to the substituted alkynylcaprolactams as a new anticonvulsant structural class.

Administration, Oral↗
PubMed1986

Effects of human exposure to atmospheric epsilon-caprolactam.

There is little published information on the human toxicology of epsilon-caprolactam, the monomer precursor of nylon 6. This paper reports an investigation of a group of eight workers who had been chronically exposed to atmospheric caprolactam levels of around 70 times the current ACGIH threshold limit value (TLV). No evidence of systemic toxicity was found, although all workers showed a greater or lesser degree of skin change in the form of peeling and/or fissuring.

Adult↗
PubMed1984

Biologic activity of epsilon-caprolactam.

In general, this literature review indicates that epsilon-caprolactam has a relatively low toxicity to humans. This low-degree of toxicity is attributable in part to its rapid elimination as demonstrated by experimental studies on animals. Human studies are mostly those based on workers in Russian factories. Although reporting physicians attributed such symptoms as general weakness, irritability, headaches, and insomnia, and such diagnoses as neurosis, neurasthenia, rapid mood shifts as well as others to excessive caprolactam exposures, the widely recognized Russian national scourge of alcoholism, particularly among working populations was not considered as a possible factor. Some of the reports recognized the complicating existence of multiple exposures in the factories such as excessively high temperatures and humidity, high noise levels, and other chemicals - including mixtures of diphenyl and diphenyl oxide, cyclohexane, benzene, and others, but most reports gave scant or no consideration to them.

Amino Acids↗
PubMed2004

Application of a sponge media (BioCube) process for upgrading and expansion of existing caprolactam wastewater treatment plant for nitrogen removal.

For the upgrade and expansion of an existing caprolactam wastewater treatment plant, a freely floating sponge media (BioCube) process was selected based on extensive pilot-plant tests, due to extreme space constraints. In order to protect nitrifier inhibition caused by high strength organics in caprolactam wastewater, the pilot plant consisted of an organics removal reactor, which functioned as a pretreatment for nitrification, and followed the nitrogen removal reactor. The suspended MLSS was 1,800-4,000 and the media attached MLSS was maintained at 22,000-26,000 mg/L. The final effluent COD was noticeably low, around 20.4-37 mg/L, even with fairly large fluctuations in the feed levels, between 1,400-6,770 mg/L. The removal of total nitrogen with the system, when denitrification was close to completion, was approximately 97.6%. For the entire run, complete nitrification of 99.6% was achieved, which might have been due to well-acclimatized nitrifiers attached in the BioCube media. Specifically, after adaptation, the nitrification continuously increased in the organics removal reactor, even under high residual organics conditions. From the numerous experimental results, the BioCube process seemed to be an effective method for the upgrading and expansion of the existing wastewater treatment plant, with minimum reactor enlargement.

Animals↗