Determination of epichlorohydrin in workplace air by gas chromatograph-electron capture detector / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To develop a method for determining epichlorohydrin in the workplace air by gas chromatograph-electron capture detector (GC-ECD).</p><p><b>METHODS</b>Epichlorohydrin in the workplace air was collected by activated charcoal tubes, desorbed using acetone, and analyzed by GC-ECD.</p><p><b>RESULTS</b>A good linearity was obtained in the range of 1.0-50 µg/mL (r=0.999 7). The detection limit was 0.012 µg/ml, while the recovery rate was 88.1% and relative standard deviation ranged from 1.11% to 3.57%. The samples could be stored for seven days at room temperature.</p><p><b>CONCLUSION</b>This method effectively eliminates the interferences of alkanes on determination of epichlorohydrin and improves the sensitivity by 1 to 2 orders of magnitude, which can solve the problem of detection limit above standard in GBZ/T 160.58-2004.</p>

Biocompatibility of human auricular chondrocytes cultured onto a chitosan/polyvynil alcohol/epichlorohydrin-based hydrogel for tissue engineering application / Biocompatibilidad de condrocitos humanos cultivados sobre un hidrogel a base de quitosano/alcohol polivnílico/epiclorhidrina para aplicación en ingeniería de tejidos

Tissue engineering (TE) has become an alternative for auricular reconstruction based on the combination of cells, molecular signals and biomaterials. Scaffolds are biomaterials that provide structural support for cell attachment and subsequent tissue development. Ideally, a scaffold should have characteristics such as biocompatibility and bioactivity to adequate support cell functions. Our purpose was to evaluate biocompatibility of microtic auricular chondrocytes seeded onto a chitosan-polyvinyl alcohol-epichlorohydrin (CS-PVA-ECH) hydrogel to propose this material as a scaffold for tissue engineering application. After being cultured onto CS-PVA-ECH hydrogels, auricular chondrocytes viability was up to 81%. SEM analysis showed cell attachment and extracellular matrix formation that was confirmed by IF detection of type II collagen and elastin, the main constituents of elastic cartilage. Expression of elastic cartilage molecular markers during in vitro expansion and during culture onto hydrogels allowed confirming auricular chondrocyte phenotype. In vivo assay of tissue formation revealed generation of neotissues with similar physical characteristics and protein composition to those found in elastic cartilage. According to our results, biocompatibility of the CS-PVA-ECH hydrogel makes it a suitable scaffold for tissue engineering application aimed to elastic cartilage regeneration.

La ingeniería de tejidos (TE) es una alternativa para la reconstrucción auricular basada en la combinación de células, señales moleculares y biomateriales. Los andamios fabricados con biomateriales brindan un soporte estructural que favorece la adhesión cellular y el desarrollo del tejido. Un andamio debe poseer características como biocompatibilidad y bioactividad para soportar adecuadamente funciones celulares. Nuestro objetivo fue evaluar la biocompatibilidad de condrocitos auriculares de microtia cultivados sobre un hidrogel a base de quitosano-alcohol polivinílico-epiclorhidrina (CS-PVA-ECH) y proponerlo como andamio con aplicaciones en ingeniería de tejidos. La viabilidad de los condrocitos auriculares es superior al 81% después de ser cultivados sobre el hidrogel. El análisis por SEM reveló la unión celular y formación de matriz extracellular sobre el hidrogel; confirmada mediante detección por IF de colágena tipo II y elastina. La expresión de marcadores moleculares durante la expansión in vitro y el cultivo sobre los hidrogeles confirmaron el fenotipo condral. El ensayo de formación de tejido in vivo demostró la generación de neotejidos con características físicas y composición similar al cartílago elástico. Nuestros resultados indican que la biocompatibilidad del hidrogel de CS-PVA-ECH lo hace un andamio adecuado para aplicaciones en ingeniería de tejidos enfocadas a regeneración de cartílago elástico.

Effect of quaternary ammonium carboxymethylchitosan on release rate in-vitro of aspirin sustained-release matrix tablets

The aim of this study was to develop a derivative of chitosan as pharmaceutical excipient used in sustained-release matrix tablets of poorly soluble drugs. A water-soluble quaternary ammonium carboxymethylchitosan was synthesized by a two-step reaction with carboxymethylchitosan [CMCTS], decylalkyl dimethyl ammonium and epichlorohydrin. The elemental analysis showed that the target product with 10.27% of the maximum grafting degree was obtained. To assess the preliminary safety of this biopolymer, cell toxicity assay was employed. In order to further investigate quaternary ammonium carboxymethylchitosan application as pharmaceutical excipient, aspirin was chosen as model drug. The effect of quaternary ammonium CMCTS on aspirin release rate from sustained-release matrix tablets was examined by in-vitrodissolution experiments. The results showed that this biopolymer had a great potential in increasing the dissolution of poorly soluble drug. With the addition of CMCTS-CEDA, the final cumulative release rate of drug rose up to 90%. After 12 h, at the grade of 10, 20 and 50 cps, the drug release rate increased from 58.1 to 90.7%, from 64.1 to 93.9%, from 69.3 to 96.1%, respectively. At the same time, aspirin release rate from sustained-release model was found to be related to the amount of quaternary ammonium CMCTS employed. With the increase of CMCTS-CEDA content, the accumulated release rate increased from 69.1% to 86.7%. The mechanism of aspirin release from sustained-release matrix tablets was also preliminary studied to be Fick diffusion. These data demonstrated that the chitosan derivative has positive effect on drug release from sustained-release matrix tablets

Determination of epichlorohydrin in drinking water by isotope dilution gas chromatography-mass spectrometry / 中华预防医学杂志

<p><b>OBJECTIVE</b>To establish a method for determination of the epichlorohydrin in drinking water by isotope dilution gas chromatography-mass spectrometry (GC-MS).</p><p><b>METHODS</b>The internal standard solution D5-epichlorohydrin was added in drinking water sample. The epichlorohydrin was firstly collected by active carbon, and the adsorbent was then centrifuged at 2739 × g for 10 min to remove water. Finally, the epichlorohydrin was desorbed by dipping the active carbon in 1.0 ml acetone for 1 h. The desorbed solution was tested by GC-MS and quantified with isotopic internal standards. The detection limit, precision and accuracy of the assay were evaluated. This method was adopted to detect the epichlorohydrin in drinking water for 25 batches in a city.</p><p><b>RESULTS</b>The determination method of epichlorohydrin represented a good linear relationship in the range of 0.0645-3.8700 µg/L, the linear regression equation was Y = 2.828X + 4.91 × 10(-2) (r > 0.999). When the epichlorohydrin concentration were 0.0806, 0.3230 and 3.2300 µg/L, the relative standard deviations (RSD) were 7.9%, 4.7% and 3.1%, respectively. The average recoveries were from 95.7% to 98.7%. The limit of detection (LOD) was 0.015 µg/L, limit of quantification (LOQ) was 0.052 µg/L. The content of epichlorohydrin in the 25 cases of drinking water was under the limit of detection.</p><p><b>CONCLUSION</b>The method is more simple than the national standard method, with high sensitivity, accuracy and good reproducibility, which is suitable for detection of the trace amounts of epichlorohydrin in drinking water.</p>

A Case of Allergic Contact Dermatitis Caused by Epichlorohydrin and tris-DMP in an Epoxy Resin Worker / 대한산업의학회지

BACKGROUND: Epoxy resin compounds are one of the common causes of occupational allergic contact dermatitis. In Korea, most cases of allergic contact dermatitis from epoxy resin compounds have been caused by the epoxy resin itself. We report a rare case of allergic contact dermatitis which was caused by epichlorohydrin, an ingredient of epoxy resin and 2,4,6-tris-(dimethylaminomethyl)phenol (tris-DMP), a kind of hardeners. CASE REPORT: A 43-year-old man, who had worked at the epoxy resin glue manufacturing factory since 1999, presented with mild and intermittent erythematous papules and rashes on his face, neck, trunk, and both arms. He was dealing with epoxy resin, epichlorohydrin, bisphenol A and hardeners. After a new hardener was added in August 2008, his skin lesions worsened from what he had experienced in the past. A skin patch test was performed to identify the causative chemicals of the skin lesion. Epichlorohydrin and tris-DMP elicited positive reactions after 48 hours and increased after 96 hours. CONCLUSION: This case confirmed occupational allergic contact dermatitis caused by epichlorohydrin and tris-DMP, an ingredient of epoxy resin and a hardener, respectively.

Preparation and studies of the adsorbent double cross-linked agar beads entrapped attapulgite clay / 生物医学工程学杂志

A method for preparing the double cross-linked agar beads entrapped attapulgite clay for hemopurification is reported. Attapulgite clay was coated with agar and cross-linked by epichlorohydrin. After the process of "drying-out", the cross-linked agar beads entrapped attapulgite clay (CAA) was cross-linked again by 10% toluene 2,4,-diisocyanate in acetone at 35 degrees C for 3 h and 30 min. The products withstood autoclaving at 121 degrees C for 30 min. The performance tests showed that the adsorption of the double cross-linked agar beads entrapped attapulgite clay (DCAA) on methylene blue was about 4 times the adsorption of CAA on methylene blue. The intensity of DCAA was raised 6 times, and the appearance of DCAA was denser. Investigation on the blood being in contact with DCAA showed: at 1 h of contact, the loss of leucocyte was <1%, of erythrocyte <5%, and of blood platelets <8%; at 2h of contact, the loss of leucocyte was <2%, of erythrocyte <10%, and of blood platelets <20%.

Acute Toxicity of Administered Bisphenol A Di Glycidyl Ether in Male Sprague Dawley Rats / 대한산업의학회지

OBJECTIVES: Bisphenol A Di Glycidyl Ether (BADGE) is the major component in commercial liquid epoxy resins, which are manufactured by co-reacting bisphenol A with epichlorohydrin. The authors investigated the acute toxicity of BADGE. METHODS: BADGE was administered by a gavage to 8 week old SPF Sprague Dawley rats in a single dose of 0 (negative control), 0.37 (Diethylstilbesterol, DES), 1000, 2000, 4000, and 8000 mg/kg/day of BADGE. Each treatment group contained 7 rats. The general status and weight of the rats were observed for 14 days. The rats were anesthetized by ether at 14 days, and the changes in morphology, organ weight, sperm count and motility, and hormone level were measured. RESULTS: All the rats treated with BADGE had diarrhea on the 1st day. The rats administered BADGE at 1000, 2000, and 4000 mg/kg/day showed a soiled perineal region and soft stools with diarrhea until the 3rd day. The 8000 mg/kg/day BADGE rats had diarrhea for two days followed by emaciation, soiled fur, a soiled perineal region, staining around the mouth and were moribund for three to eight days. No weight gain was observed after the 1st day in the 2000, 4000, and 8000 mg/kg/day BADGE rats and after the 7th day in all the treatment groups compared with the control groups. Some treatment groups were observed to have a decrease in the weight of the heart (BADGE 1000, 2000 and 4000 mg/kg/day), liver (BADGE 1000, 2000, 4000 and 8000 mg/kg/day) and prostate (BADGE 4000 mg/kg/day) compared with control group. The weight of the liver was significantly lower in all treatment groups compared with the control group. The relative weight of the liver (BADGE 1000 and 4000 mg/kg/day) was significant lower than the control. No pathological changes were observed in the brain, liver, thyroid, heart, spleen, kidney, lung and prostate. The number of spermatid in the seminiferous tubule in the testes was lower in all treatment groups than the control. The sperm motility tended to decrease with increasing concentration but the sperm count was similar in all treatment groups. The plasma Estrogen and testosterone level were similar in the control and treatment groups. CONCLUSIONS: These results suggest that BADGE induces general, hepatic and reproductive toxicity at 1000 mg/kg/day.

Epichlorohydrin induced biochemical changes in the rose-ringed parakeet, Psittacula krameri Scopoli.

Intraperitoneal administration of epichlorohydrin (ECH) at the dose level of 20 and 50 mg/kg body weight inhibited spermatogenesis in the testis of parakeet during breeding season. A total load of 60 mg/kg body weight of ECH given on 3 consecutive days proved to be lethal. Testicular proteins, nucleic acids (DNA and RNA), phospholipids and acid phosphatase activity were decreased, while the lipids, total cholesterol and alkaline phosphatase activity increased after ECH administration. The results suggest that the testicular atrophy caused by ECH was associated with an alteration in the activities of macromolecules and enzymes related to specific events of spermatogenesis.

Chemical study of the alkylation of benzimidazole-2thiol and benzothiazole-2thiol with epichlorohydrin

Three isomeric products [3a and 4b] were obtained from the alkylation of [1] with epichlorohydrin under different reaction conditions. The epoxide [3a] was found to be convertible to [4a], while [4a] and [4b] were nonconvertible to each other and proved to be stereo- isomers. Mechanisms of formation of these isomers were attempted. Alkylation of [2] with epichlorohydrin was epichlorohydrin was also investigated and shown to produce [10] or [11]. Structures of the final products were evidenced by spectroscopic data and variable routes of synthesis