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PubMed1993

Metabolism and pharmacokinetics of deuterium-labelled di-2-(ethylhexyl) adipate (DEHA) in humans.

The metabolism and pharmacokinetics of [2H10]di-2-(ethylhexyl) adipate (DEHA) labelled on the ethyl side-chains was determined in six male volunteers. The dose administered was 46 mg [2H10]DEHA given orally. No parent molecule was found in plasma; however, the metabolite [2H5]2-ethylhexanoic acid (EHA) was detected (mean rate of formation: 1.63 +/- 1.19/hr; mean rate of elimination: 0.42 +/- 0.1/hr). Further oxidative metabolism products were detected in urine; the dominant metabolite identified was EHA present as a conjugate and accounted for an average of 8.6% of the administered dose. [2H5]2-Ethyl-5-hydroxyhexanoic acid, [2H5]2-ethylhexanedioic acid, [2H5]2-ethyl-5-keto-hexanoic acid and [2H5]2-ethylhexanol together accounted for a further 3.5% of the dose. The fate of the remainder was not determined.

Adipates↗
PubMed2006

Surface modification of poly(tetramethylene adipate-co-terephthalate) membrane via layer-by-layer assembly of chitosan and dextran sulfate polyelectrolyte multiplayer.

The improvement of hydrophilicity and hemocompatibility of poly(tetramethylene adipate-co-terephthalate) (PTAT) membrane was developed via polyelectrolyte multilayers (PEMs) immobilization. The polysaccharide PEMs included chitosan (CS, as a positive-charged and antibacterial agent) and dextran sulfate (DS, as a negative-charged and anti-adhesive agent) were successfully prepared using the aminolyzed PTAT membrane in a layer-by-layer (LBL) self-assembly manner. The obtained results showed that the contact angle of as-modified PTAT membranes reached to the steady value after four bilayers of coating, hence suggesting that the full coverage was achieved. It could be found that the PTAT-PEMs membranes with DS as the outmost layer could resist the platelet adhesion and human plasma fibrinogen (HPF) adsorption, thereby prolonging effectively the blood coagulation times. According to L929 fibroblast cell growth inhibition index, the as-prepared PTAT membranes exhibited non-cytotoxic. Overall results demonstrated that such an easy, valid and shape-independent processing should be potential for surface modification of PTAT membrane in the application of hemodialysis devices.

Adipates↗
PubMed2006

Migration of di(2-ethylhexyl) adipate and acetyltributyl citrate plasticizers from food-grade PVC film into sweetened sesame paste (halawa tehineh): kinetic and penetration study.

Food-grade polyvinyl chloride (PVC) cling-film containing 5.3% (w/w) di(2-ethylhexyl) adipate (DEHA) and 3.0% (w/w) acetyltributyl citrate (ATBC) plasticizers was used to wrap halawa tehineh (halva) samples. Samples were split into two groups and stored at 25+/-1 degrees C. One group was analyzed for DEHA and ATBC content at intervals between 0.5 and 240h of contact (kinetic study) and a second group was cut into slices (1.5mm thick) after 240h of halva/PVC contact and was analyzed for DEHA and ATBC content (penetration study). Determination of both plasticizers was performed using a direct gas chromatographic (GC) method after extraction of DEHA from halva samples. DEHA readily migrated into halva samples: the equilibrium amount of DEHA in halva (3.31mg/dm(2) film or 81.4mg/kg halva) corresponding to a loss of 54.7% (w/w) DEHA from PVC film. This value is slightly higher than the limit of 3mg/dm(2) of film surface set by the European Union for DEHA. The equilibrium amount of ATBC in halva was 1.46mg/dm(2) (36.1mg/kg) corresponding to a loss of 42.7% ATBC from PVC film. With regard to the penetration of both placticizers into halva samples, migration of DEHA was detectable up to the 7th slice beneath the surface of halva (total depth 10.5mm) while the migration of ATBC was detectable up to the 5th slice (total depth 7.5mm).

Adipates↗
PubMedDate not supplied

Antiandrogenic effects in male rats perinatally exposed to a mixture of di(2-ethylhexyl) phthalate and di(2-ethylhexyl) adipate.

Di(2-ethylhexyl) phthalate (DEHP) is a well-known testicular toxicant inducing adverse effects in androgen responsive tissues. Therefore, di(2-ethylhexyl) adipate (DEHA) is currently being evaluated as a potential substitute for DEHP. Similarities in structure and metabolism of DEHP and DEHA have led to the hypothesis that DEHA can modulate the effects of DEHP. Wistar rats were gavaged with either vehicle, DEHP (300 or 750mg/kg bw/day) or DEHP (750mg/kg bw/day) in combination with DEHA (400mg/kg bw/day) from gestation day (GD) 7 to postnatal day (PND) 17. Decreased anogenital distance (AGD) and retention of nipples in male offspring were found in all three exposed groups. Dosed males exhibited decreased weights of ventral prostate and m. levator ani/bulbocavernosus. Histopathological investigations revealed alterations in testis morphology in both juvenile and adult animals. The litter size was decreased and postnatal mortality was increased in the combination group only, which is likely a combined effect of DEHP and DEHA. However, no combination effect was seen with respect to antiandrogenic effects, as males receiving DEHP in combination with DEHA did not exhibit more pronounced effects in the reproductive system than males receiving DEHP alone.

Adipates↗
PubMed2006

Toxicity of di(2-ethylhexyl)phthalate (DEHP) and di(2-ethylhexyl)adipate (DEHA) under conditions of renal dysfunction induced with folic acid in rats: enhancement of male reproductive toxicity of DEHP is associated with an increase of the mono-derivative.

F344 male rats were given five consecutive weekly subcutaneous injections of folic acid for induction of chronic renal dysfunction and then di(2-ethylhexyl)phthalate (DEHP) or di(2-ethylhexyl)adipate (DEHA) in the diet at a concentration of 0, 6000 or 25,000 ppm for 4 weeks in order to investigate whether male reproductive toxicity of the two chemicals might be enhanced under conditions of renal disease. Control animals also received DEHP or DEHA in the same manner but without folic acid pretreatment. Decreased testicular weights, seminiferous atrophy with vacuolization of sertoli cells and diminished sperm counts were more prominent in rats given folic acid and then 25,000 ppm DEHP as compared to those exposed to DEHP alone. No such reproductive toxicity was evident in rats given 6000 ppm DEHP or either dose of DEHA. An increased concentration of the mono-derivative of DEHP (mono(2-ethylhexyl)phthalate, MEHP) in the blood, testis and urine was considered relevant to the enhanced reproductive toxicity observed with DEHP.

Adipates↗
PubMedDate not supplied

Biodegradation of poly(ethylene adipate) microcapsules in physiological media.

Spherical reservoir-type microcapsules fabricated using a water/oil/water (W/O/W) double emulsion technique with solvent evaporation and composed of poly(ethylene adipate) (PEAD) blended with 20% poly-epsilon-caprolactone (PCL II) containing a range of bovine serum albumin (BSA) loadings were incubated in Hank's buffer, pH 7.4, newborn calf serum, 1.5% pancreatin and synthetic gastric juice containing 10% pepsin A over 30 days and their percentage weight loss (PWL) and changes in ultrastructural morphology monitored by gravimetry and stereoscan electron microscopy (SEM) respectively. The greatest PWL from microcapsules was observed after incubation in newborn calf serum (NCS) and pancreatin and decreased in the order NCS > pancreatin > synthetic gastric juice > Hank's buffer. Only microcapsules theoretically loaded with 5-20% BSA and incubated in synthetic gastric juice showed a significant increase in PWL with increasing percentage BSA loading. The structural biodegradation of PEAD microcapsules in both Hank's buffer and synthetic gastric juice was minimal whilst the morphological changes observed during incubation in NCS involved pitting of the membrane, some surface erosion and reduction in diameter, followed by microcapsule membrane disruption and loss of reservoir contents. Biodegradation in pancreatin was associated with surface flaking and loss of large fragments of the microcapsule membrane. Only in NCS and pancreatin, where one would expect to see the effects of enzyme activity in addition to simple ester hydrolysis, did biodegradation proceed to the stage where there was a loss of spherical shape and almost total disruption of the microcapsule structure within 30 days.

Adipates↗
PubMed2000

Sterilization, storage stability and in vivo biocompatibility of poly(trimethylene carbonate)/poly(adipic anhydride) blends.

Biodegradable blends of poly(trimethylene carbonate) (PTMC) and poly(adipic anhydride) (PAA) have been proven to be strong candidates for controlled drug delivery polymers in vitro. We now report on the stability, sterilizability and in vivo local tissue response of these matrices. Blend matrices were sterilized by beta-radiation or ethylene oxide gas treatment, stored at different times and temperatures, and analyzed for changes in physicochemical properties. Moisture uptake at different relative humidities and storage times was determined. Sterilization procedures induced hydrolysis of the matrices. Ethylene oxide gas sterilization had a significantly more marked effect upon the matrix properties than radiation treatment. The onset of degradation was reflected in a decrease of crystallinity and molecular weight along with a change of blend composition. A similar onset of matrix degradation was observed upon storage in air. The physicochemical properties of the blends were well preserved upon storage under argon atmosphere. Biocompatibility of PTMC/PAA implants was assessed in the anterior chamber of rabbits eyes for 1 month. At selected post-operative time points, aqueous humor was analyzed for white blood cells and the corneal thickness was measured. The results suggest good biocompatability of PTMC-rich matrices, whereas fast eroding PAA-rich matrices caused inflammatory responses, due to a burst release of degradation products.

Adipates↗
PubMed1997

Comparison of the effects of di-(2-ethylhexyl)adipate on hepatic peroxisome proliferation and cell replication in the rat and mouse.

The effects of di-(2-ethylhexyl)adipate (DEHA) have been compared in female F344 rats and female B6C3F1 mice fed diets containing 0-4.0% DEHA and 0-2.5% DEHA, respectively, for periods of 1, 4 and 13 weeks. In both the rat and mouse treatment with DEHA at all time points produced a dose-dependent increase in relative liver weight and hepatic peroxisome proliferation as demonstrated by the induction of peroxisomal (cyanide-insensitive palmitoyl-CoA oxidation) and microsomal (lauric acid 12-hydroxylase) fatty acid oxidising enzyme activities. The magnitude of induction of peroxisome proliferation was similar in both species. Replicative DNA synthesis was studied by implanting osmotic pumps containing 5-bromo-2'-deoxyuridine during study weeks 0-1, 3-4 and 12-13. After 1 week DEHA treatment hepatocyte labelling index values were increased in rats given 2.5 and 4.0% DEHA and mice given 0.6-2.5% DEHA. While DEHA treatment for 4 and 13 weeks did not increase labelling index values in the rat, a sustained stimulation of replicative DNA synthesis was observed in mice given 1.2 and 2.5% DEHA. The results of this study demonstrate a species difference in the hepatic effects of DEHA, in that at some dose levels DEHA can produce a sustained stimulation of replicative DNA synthesis in mouse but not in rat liver. Sustained cell replication provides a better correlation with the observed formation of liver tumours in chronic studies with DEHA in female mice, but not in female rats, than the magnitude of stimulation of hepatic peroxisome proliferation.

Adipates↗
PubMedDate not supplied

Molecular mobility and phase structure of biodegradable poly(butylene succinate) and poly(butylene succinate-co-butylene adipate).

Molecular mobility and phase structure of biodegradable poly(butylene succinate) (PBS) and poly(butylene succinate-co-20 mol % butylene adipate) [P(BS-co-20 mol % BA)] have been investigated by high-resolution solid-state (13)C NMR. For both samples, two components with different (13)C spin-lattice relaxation time (T(1C)) values have been observed in the crystalline region. The crystalline component with shorter T(1C) value is assignable to the interface near amorphous phase. The crystalline component with longer T(1C) value is ascribed to the inside of the crystalline region. On the basis of T(1C), it has been concluded that the BA units are not included in the crystalline region of P(BS-co-20 mol % BA). Molecular mobility and higher-ordered structure of amorphous phase have been also compared between the melt and solid state. Variable-temperature high-resolution (13)C NMR measurements for the amorphous phase have revealed the remarkable difference in dynamics and structure between the melt and solid state.

Adipates↗
PubMed1999

Determination of the cross-linking effect of adipic acid dihydrazide on glycoconjugate preparation.

The cross-linking effect of adipic acid dihydrazide (ADH) on polysaccharide derivatization can be evaluated by applying combination of elemental analysis and colorimetric assay. Elemental analysis is used for estimation of total ADH bound to polysaccharide and a colorimetric trinitrobenzene sulfonic acid assay is used to determine the part of ADH not involved in cross-linking. The difference of values expressed as molar ratios (per repeating unit) provides information on the amount of ADH involved in cross-linking the polysaccharides. Carboxymethylated polysaccharides were derivatized with different amounts of ADH to test the procedure. Analytical results showed that excess of ADH in the reaction only slightly decreased the cross-linking. The number of carboxyl groups remained unmodified even at high excess of ADH and high concentration of carbodiimide (EDC) coupling reagent.

Adipates↗
PubMed1995

Production of cephalosporin intermediates by feeding adipic acid to recombinant Penicillium chrysogenum strains expressing ring expansion activity.

We demonstrate a novel and efficient bioprocess for production of the cephalosporin intermediates, 7-aminocephalosporanic acid (7-ACA) or 7-amino deacetoxycephalosporanic acid (7-ADCA). The Streptomyces clavuligerus expandase gene or the Cephalosporium acremonium expandase-hydroxylase gene, with and without the acetyltransferase gene, were expressed in a penicillin production strain of Penicillium chrysogenum. Growth of these transformants in media containing adipic acid as the side chain precursor resulted in efficient production of cephalosporins having an adipyl side chain, proving that adipyl-6-APA is a substrate for either enzyme in vivo. Strains expressing expandase produced adipyl-7-ADCA, whereas strains expressing expandase-hydroxylase produced both adipyl-7-ADCA and adipyl-7-ADAC (aminodeacetylcephalosporanic acid). Strains expressing expandase-hydroxylase and acetyltransferase produced adipyl-7-ADCA, adipyl-7-ADAC and adipyl-7-ACA. The adipyl side chain of these cephalosporins was easily removed with a Pseudomonas-derived amidase to yield the cephalosporin intermediates.

Acetyltransferases↗
PubMed2001

Eleven phthalate esters and di(2-ethylhexyl) adipate in one-week duplicate diet samples obtained from hospitals and their estimated daily intake.

Plasticizers in duplicate diet samples obtained over 1 week were analysed in order to estimate daily intake. The phthalate esters were as follows: diethyl, dipropyl, dibutyl, dipentyl, dihexyl, butylbenzyl, dicyclohexyl, di(2-ethylhexyl), dioctyl, diisooctyl (mixture of isomers) and diisononyl (mixture). Di(2-ethylhexyl) adipate was also determined. Homogenized samples of composite meals were extracted with acetonitrile, lipids were removed by extraction into n-hexane and the acetonitrile layer was cleaned using Florisil and Bondesil PSA dual layer column. Phthalates were determined by GC/MS (SIM). Phthalate recovery from the fortified food mixture by this method was 62.5-140.8%. Quality assurance as assessed by three laboratories indicated coefficient of variance in the levels of detected phthalates in same lot samples as below 10%. Detection limits were 0.1-23 ng/g for each phthalate. One-week duplicate diet samples provided by three hospitals in three remote prefectures of Japan were analysed as individual meals. In all 63 samples, DEHP was present at the highest level among all phthalates in the range 10-4400 ng/g. The intake of plasticizers estimated from all samples was 519 microg DEHP/day, 86 microg DEHA/day, 65 microg DINP/day, and 4.7 microg BBP/day. Calculated DEHP in 2-day samples out of 21 days exceeded EU TDI for a person of 50 kg body weight (1850 microg per day). Disposable PVC gloves used during the preparation of meals were suspected as the source of the high DEHP content. One-day intake of the other phthalates and DEHA was below 7% of TDI in all cases. High concentrations of DEHP (5990 ng/g) was found in baby food used in quality assurance work. The source of contamination was the PVC-tube used during production and was effectively reduced by replacing the tube by one made of stainless steel.

Adipates↗
PubMedDate not supplied

Migration from plasticized films into foods. 1. Migration of di-(2-ethylhexyl)adipate from PVC films during home-use and microwave cooking.

Migration of di-(2-ethylhexyl)adipate (DEHA) into a diverse range of foods arising from the domestic use of plasticized PVC films has been determined using a stable isotope dilution GC/MS procedure. Aspects of home use reported in this study include the wrapping and covering of foods such as cheese, cooked meats, sandwiches, cakes, fresh fruit and vegetables; the use of films during food preparation such as marinading; covering during microwave reheating of previously prepared foods, and covering during microwave cooking. Contact between film and foods was for differing temperatures and times, representative of the range of conditions likely to be experienced in practice in the home. Migration increased with both the length of contact time and temperature of exposure, with the highest levels observed where there was a direct contact between the film and food, and where the latter had a high fat content on the contact surface. Highest levels of migration were observed for cheese, cooked meats, cakes and for microwave-cooked foods, whilst lower levels were observed for wrapping of unfilled sandwiches, fruit and vegetables (except avocado), and for food preparation including microwave reheating where there was covering of the food in a container but little or no direct contact.

Adipates↗
PubMedDate not supplied

Migration from plasticized films into foods. 2. Migration of di-(2-ethylhexyl)adipate from PVC films used for retail food packaging.

A UK survey of di-(2-ethylhexyl)adipate (DEHA) levels in retail foods (83 samples) wrapped in plasticized PVC film has been carried out, examining a wide range of different food types obtained from retail and take-away outlets. Foodstuffs analysed included fresh meat and poultry, ready-cooked poultry, cheese, fruit, vegetables and baked goods such as cakes, bread rolls and sandwiches. Analysis by stable isotope dilution GC/MS showed DEHA levels ranging from 1.0 to 72.8 mg/kg in uncooked meat and poultry, 9.4 to 48.6 mg/kg in cooked chicken portions, 27.8 to 135.0 mg/kg in cheese, less than 2.0 mg/kg in fruit and vegetables and 11 to 212 mg/kg in baked goods and sandwiches. The level of DEHA migration correlated with the extent of contact between the film and exposed fatty portions of the food, whether that was the mayonnaise filling of a sandwich or the surface fat from a joint of uncooked meat. The level of DEHA in meat exposed to plasticized film was not reduced significantly by volatilization or chemical transformation on subsequent cooking by grilling or frying.

Adipates↗
PubMedDate not supplied

Evaluation of a predictive mathematical model of di-(2-ethylhexyl) adipate plasticizer migration from PVC film into foods.

The diffusion coefficient of the plasticizer di-(2-ethylhexyl)adipate (DEHA) in Cheddar cheese (Df) was determined by measuring the extent to which DEHA penetrated cheese that was placed in intimate contact with artificially DEHA-contaminated cheese. Slices (20 microns) of cheese from the boundary layer, into which DEHA had migrated, were microtomed at -40 degrees C, and analyzed for DEHA by gas chromatography (GC). Mean values of Df determined by graph fitting experimental and calculated data were 1.5 x 10(-9) cm2 s-1 at 5 degrees C and 3.0 x 10(-8) cm2 s-1 at 25 degrees C. The partition coefficient (K) of DEHA between cheese and PVC film was derived from the partition coefficients of DEHA between acetonitrile (ACN) and cheese lipid, ACN and cheese solid, and ACN and PVC film. The mean values of K between cheese and PVC film were estimated to be 0.70 at 5 degrees C and 0.58 at 25 degrees C. The estimated values of Df and K were then used in a mathematical model (Till et al. 1982) to predict migration levels of DEHA into cheese. Good agreement with previously published experimental data was obtained. Extrapolation of the prediction of DEHA migration into fatty foods, such as salami and avocado, was also successful (ratio of experimental to predicted results within a factor of two). The values of Df and K for cheese are, however, inappropriate for modelling non-fatty foods such as meat, cakes, fruit and vegetables. Predicted values for these foods were typically 3-10-fold too high. More accurate predictions would probably be obtained if values of Df more relevant to these foods are used. The predictions were relatively insensitive to the value of K.

Adipates↗
PubMedDate not supplied

The occurrence of phthalate ester and di-2-ethylhexyl adipate plasticizers in Canadian packaging and food sampled in 1985-1989: a survey.

Selected foods (260 samples) packaged in materials with the potential to contribute plasticizers to the food, and available food composites (98 samples) obtained from the Canadian Health Protection Branch Total Diet Program, were analysed for phthalate plasticizers and di-2-ethylhexyl adipate (DEHA). The available contacting packaging was also analysed for plasticizers. The results show DEHA in food-contacting film and as a migrant in store-wrapped meat, poultry, fish, cheese and ready-to-eat foods at levels as high as 310 micrograms/g (cheese). DEHA levels in unheated film-wrapped ready-to-eat foods were increased by heating. The di-2-ethylhexyl, dibutyl, butylbenzyl and diethyl phthalate esters (DEHP, DBP, BBP and DEP, respectively) were also found in both the packaging and the contacted foods. Low levels of DEHP (0.065 micrograms/g, average in beverages and 0.29 micrograms/g, average in foods) associated with the use of DEHP-plasticized cap or lid seals, were found in a variety of glass-packaged foods; DBP, BBP and DEHP were found, as previously described, in butter and margarine as migrants from the aluminium foil-paper laminates; and DEP in pies at 1.8 micrograms/g (average) as a migrant from the pie carton windows. In most cases, plasticizers detected in the food were also found in the associated packaging. When possible, 'core' or non-contacting food portions were analysed to verify the migration phenomena.

Adipates↗
PubMed1998

Specific migration of di-(2-ethylhexyl)adipate (DEHA) from plasticized PVC film: results from an enforcement campaign.

A control campaign on the correct labelling of plasticized PVC film according to current legislation on food contact materials has been performed. Analytical methods based on the isotope dilution technique were developed. For enforcement purposes, the films were exposed to the official food simulant, olive oil, followed by clean-up using size exclusion chromatography and final determination of di-(2-ethylhexyl) adipate (DEHA) by combined capillary gas chromatography and mass spectrometry (GC-MS). In the initial screening, the samples were exposed to the alternative food simulant, isooctane, and DEHA could be determined by GC-MS without further clean-up. A good consistency between results from the two different methods was obtained. During the campaign, 49 samples of PVC films, the majority intended for use in retail shops, were sampled from importers and wholesalers by the Municipal Food Control Units. Initially, all films were screened for the migration into isooctane (exposed 2 h at 40 degrees C) of DEHA and other potentially present low molecular weight plasticizers using full scanning mass spectrometry. Films showing a substantial migration of DEHA were further tested with olive oil according to the declared field of application (exposed for 10 days at 40 degrees C). In 47 of the 49 films the migrate contained a substantial amount of DEHA. In 46 films the migration exceeded the specific migration limit of 3 mg/dm2 after use of the relevant reduction factor given in legislation. However, because of the general uncertainty of the analytical method and because the variation in the thickness of the films was calculated to be 1 mg/dm2, the action limit in this campaign was 4 mg/cm2. A migration higher than this action limit was found in 42 films (89% of the samples) and these films were deemed to be illegal according to their present declared field of application as given by their labelling. In a few cases, some migration of the plasticizer di-n-butyl phthalate was seen.

Adipates↗
PubMed1985

Direct determination of adipic acid in urine by extractive alkylation.

Extractive alkylation procedures are shown to be inhibited by low levels of Cl-. The chloride concentration may be reduced by mercury(II) complexation and dilution. The mercury(II) also enhances the reaction yield through some undetermined mechanism. Minor modifications of procedures for standards allow direct determination of adipic acid in urine.

Adipates↗