Abstract  A GC/MS method was developed for the identification and quantification of 14 phthalates: 8 phthalates classified H360 (DBP, DEHP, BBP, DMEP, DnPP, DiPP, DPP and DiBP), 3 phthalates proposed to be forbidden in medical devices (DnOP, DiNP and DiDP) and 3 other phthalates none regulated (DMP, DCHP and DEP) which may interfere with hormone function. In order to identify and quantify other plasticizers that are commonly used in PVC medical devices such as DEHP substitute, 5 non-phthalate plasticizers (ATBC, DEHA, DEHT, TOTM, and DINCH) were included in this study. Analyses are carried out on a GC/MS system with electron impact ionization mode (EI). The separation of plasticizers is obtained on a cross-linked 5%-phenyl/95%-dimethylpolysiloxane capillary column 30m×0.25mm (i.d.)×0.25μm film thickness using a gradient temperature. Compounds quantification is performed by external calibration using an internal standard. Validation elements on standard solutions were determined using the ISO 12787 standard approach. Plasticizers are extracted from PVC medical devices using THF for dissolving the PVC part of the sample followed by precipitation of the PVC by addition of ethanol. The supernatant is injected into a GC/MS system after dilution in ethanol. Different validation elements, including extraction recoveries for all compounds or for DEHP a cross-validation of the extraction process using the European pharmacopoeia monograph 3.1.14 as reference method, are discussed. Results obtained on 61 medical devices in PVC and 12 raw materials used as plasticizers are given.

Abstract  Electrochemical degradation of 2,5-dichloro-1,4-phenylenediamine (DP) in aqueous solution by anodic oxidation was investigated. Linear sweep voltammograms and cyclic voltammograms were studied. The influence of operating parameters on electrochemical oxidation of DP was studied as a function of the current density, initial pH, and initial concentration of DP. The degradation kinetics analysis indicated that the electrochemical degradation of DP followed a first-order reaction. The degradation intermediates during electrochemical oxidation were analyzed by UV-vis spectrophotometer, ionic chromatograph (IC), and gas chromatography/mass spectrometry (GC/MS). The combustion efficiency of DP at the anode was also estimated. The electrochemical oxidation of DP resulted in the release of NH4(+) and Cl(-). Based on these results, a degradation mechanism for electrochemical degradation of DP by anodic oxidation was proposed.

Abstract  The decomposition of azodicarbonamide, used as foaming agent in PVCplasticizer (1/1) plastisols was studied by DSC. Nineteen different plasticizers, all belonging to the ester family, two being polymeric (polyadipates), were compared. The temperature of maximum decomposition rate (in anisothermal regime at 5 K min(-1) scanning rate), ranges between 434 and 452 K. The heat of decomposition ranges between 8.7 and 12.5 J g(-1). Some trends of variation of these parameters appear significant and are discussed in terms of solvent (matrix) and viscosity effects on the decomposition reactions. The shear modulus at 1 Hz frequency was determined at the temperature of maximum rate of foaming agent decomposition, and differs significantly from a sample to another. The foam density was determined at ambient temperature and the volume fraction of bubbles was used as criterion to judge the efficiency of the foaming process. The results reveal the existence of an optimal shear modulus of the order of 2 kPa that corresponds roughly to plasticizer molar masses of the order of 450 +/- 50 g mol(-1). Heavier plasticizers, especially polymeric ones are too difficult to deform. Lighter plasticizers such as diethyl phthalate (DEP) deform too easily and presumably facilitate bubble collapse. POLYM. ENG. SCI., 2013. (c) 2012 Society of Plastics Engineers

Abstract  Thermal and nonthermal effects originating when a system is subjected to a microwave radiation field in the TiO2-photocatalyzed transformation of model substances containing various functional groups (e.g., benzoic acid, phthalic acid, o-formylbenzoic acid, phthalaldehyde, succinic acid, dimethyl phthalate, diethyl phthalate, and phenol) have been examined under simultaneous irradiation by ultraviolet (UV) and microwave (MW) radiations. Characteristics of the microwave effects and the fate of each substrate during the microwave-assisted photocatalytic process were monitored by UV absorption spectroscopy, HPLC methods, total organic carbon assays, and identification of intermediates using electrospray mass spectral techniques. Microwave thermal and nonthermal effects were delineated by comparing results from MW-generated internal heat versus conventional external heating, and at constant ambient temperature under a microwave field. Factors involved in the nonthermal component of the microwave radiation were inferred for the initial adsorption of the substrate and its subsequent degradation occurring on the surface of TiO2 particles. Microwave effects bear on the mechanism through which a model substrate undergoes oxidative degradation. A characteristic feature of these effects was briefly examined by considering the behavior of polar (dipole moments) substrates in a microwave radiation field.

Abstract  As we have known, with the plasticizer disturbance in 2011 in Taiwan, long-term exposure to diethyl phthalate (DEP), one of the widely used phthalate esters, can lead to serious health problems. Therefore, a highly sensitive indirect competitive enzyme-linked immunosorbent assay (ic-ELISA) by antigen-coated plate format for DEP in foods was proposed in this paper. The polyclonal antibodies were raised against diethyl 4-aminophthalate (4-DEAP) conjugated to bovine serum albumin by the amino diazotization linkage method. Coating antigen was prepared with 4-DEAP conjugated to ovalbumin using the same procedure. Under the optimal experimental conditions, the ic-ELISA has a linear working range of 0.005-18.6 ng/mL (R (2) = 0.9921), with a limit of detection of 0.0049 ng/mL. Low cross-reactivity (< 9 %) to structurally related phthalates was observed. The method was successfully applied to the determination of DEP in fruit juice, milky tea, pure milk, and sour milk, without purification or preconcentration. Satisfactory recoveries were obtained ranging from 91.1 to 109.3 %. The results suggested that the developed ic-ELISA is a simple, sensitive, and specific method for the rapid monitoring of DEP in food samples.

Abstract  High-throughput screening (HTPS) assays to detect inhibitors of thyroperoxidase (TPO), the enzymatic catalyst for thyroid hormone (TH) synthesis, are not currently available. Herein we describe the development of a HTPS TPO inhibition assay. Rat thyroid microsomes and a fluorescent peroxidase substrate, Amplex UltraRed (AUR, LifeTechnologies), were employed in an endpoint assay for comparison to the existing kinetic guaiacol (GUA) oxidation assay. Following optimization of assay metrics including Z', dynamic range, and activity using methimazole (MMI), the assay was tested with a 21-chemical training set. The potency of MMI-induced TPO inhibition was greater with AUR compared to GUA. The dynamic range and Z' score with MMI were as follows: 127-fold and 0.62 for the GUA assay, 18-fold and 0.86 for the 96-well AUR assay, and 11.5-fold and 0.93 for the 384-well AUR assay. The 384-well AUR assay drastically reduced animal use, requiring one-tenth of the rat thyroid microsomal protein needed for the GUA 96-well format assay. Fourteen chemicals inhibited TPO, with a relative potency ranking of MMI > ethylene thiourea > 6-propylthiouracil > 2,2',4,4'-tetrahydroxy-benzophenone > 2-mercaptobenzothiazole > 3-amino-1,2,4-triazole > genistein > 4-propoxyphenol > sulfamethazine > daidzein > 4-nonylphenol > triclosan > iopanoic acid > resorcinol. These data demonstrate the capacity of this assay to detect diverse TPO inhibitors. Seven chemicals acted as negatives: 2-hydroxy-4-methoxybenzophenone, dibutylphthalate, diethylhexylphthalate, diethylphthalate, 3,5-dimethylpyrazole-1-methanol, methyl 2-methyl-benzoate, and sodium perchlorate. This assay could be used to screen large numbers of chemicals as an integral component of a tiered TH-disruptor screening approach.

Abstract  A copolymer of divinylbenzene and N-vinyl pyrrolidone (DVB-NVP) was synthesized for the purpose of solid phase extraction (SPE). Its performance as an SPE resin was evaluated using six model compounds having different polarities. Aqueous samples containing those compounds were applied to SPE cartridges containing the aforementioned copolymer as well as the classic C18 and Oasis HLB for comparison, and the SPE processed samples were analyzed by using high performance liquid chromatography (HPLC) for quantitation. Then, the copolymer DVB-NVP was sulfonated to modify the surface properties. The surface modified materials were used to analyse complex samples. The results showed that DVB-NVP had high recoveries for the six compounds ranging from 95.55% to 101.08% which were better than those of the C18 and were comparable to those of Oasis HLB. In applying to real samples, the recoveries for dimethyl phthalate, diethyl phthalate and dibutyl phthalate in liquor were 102.55%, 102.99% and 102.11%, with the RSDs of 2.11%, 1.69%, 0.79% respectively. Similarly, the recoveries for clonidine and cyproheptadine in pork were 89.23% and 91.42% with the RSDs of 8.21% and 8.86%, respectively.

Abstract  The toxicity of phthalates is an important concern in the fields of environmental health and toxicology. Dermal exposure via skin care products, soil, and dust is a main route for phthalate delivery. We had explored the effect of topically-applied phthalates on skin absorption and toxicity. Immunohistology, functional proteomics, and Western blotting were employed as methodologies for validating phthalate toxicity. Among 5 phthalates tested, di(2-ethylhexyl)phthalate (DEHP) showed the highest skin reservoir. Only diethyl phthalate (DEP) and dibutyl phthalate (DBP) could penetrate across skin. Strat-M(®) membrane could be used as permeation barrier for predicting phthalate penetration through skin. The accumulation of DEHP in hair follicles was ∼15nmol/cm(2), which was significantly greater than DBP and DEP. DBP induced apoptosis of keratinocytes and fibroblasts via caspase-3 activation. This result was confirmed by downregulation of 14-3-3 and immunohistology of TUNEL. On the other hand, the HSP60 overexpression and immunostaining of COX-2 suggested inflammatory response induced by DEP and DEHP. The proteomic profiling verified the role of calcium homeostasis on skin inflammation. Some proteins investigated in this study can be sensitive biomarkers for dermal toxicity of phthalates. These included HSPs, 14-3-3, and cytokeratin. This work provided novel platforms for examining phthalate toxicity on skin.

Abstract  Herbals such as Ixora coccinea, Daemia extensa and Tridax procumbens were selected to screen in vitro antibacterial and immunostimulant activity against the freshwater fish pathogen Aeromonas hydrophila using different organic polar and non-polar solvents. Initial screening results revealed that, ethyl acetate extracts and its purified fraction of I. coccinea was able to suppress the A. hydrophila strains at more than 15 mm of zone of inhibition and positive immunostimulant activity. The purified active fraction, which eluted from H40: EA60 mobile phase was structurally characterized by GC-MS analysis. Two compounds such as Diethyl Phthalate (1,2-Benzene dicarboxylic acid, monobutyl ester) and Dibutyl Phthalate were characterized using NIST database search. In order to study the in vivo immunostimulant influence of the compounds, the crude extracts (ICE) and purified fractions (ICF) were incorporated to the artificial diets at the concentration of 400 mg kg(-1) and fed to the ornamental gold fish Carassius auratus for 30 days. After termination of feeding experiment, they were challenged with highly virulent A. hydrophila AHV-1 which was isolated from infected gold fish and studied the survival, specific bacterial load reduction, serum biochemistry, haematology, immunology and histological parameters. The control diet fed fishes succumbed to death within five days at 100% mortality whereas ICE and ICF fed groups survived 60 and 80% respectively after 10 days. The diets also helped to decrease the Aeromonas load after challenge and significantly (P ≤ 0.01) improved the serum albumin, globulin and protein. The diets also helped to increase the RBC and haemoglobin level significantly (P ≤ 0.05) from the control group. Surprisingly the immunological parameters like phagocytic activity, serum bactericidal activity and lysozyme activity were significantly increased (P ≤ 0.001) in the experimental diets. Macrophages and erythrocytes were abundantly expressed in the treated groups and the present work concluded that, the Phthalate derivatives from I. coccinea helps to stimulate the immune system against A. hydrophila challenge in C. auratus.

Abstract  A liquid obeys isochronal superposition if its dynamics is invariant along the isochrones in the thermodynamic phase diagram (the curves of constant relaxation time). This paper introduces two quantitative measures of isochronal superposition. The measures are used to test the following six liquids for isochronal superposition: 1,2,6 hexanetriol, glycerol, polyphenyl ether, diethyl phthalate, tetramethyl tetraphenyl trisiloxane, and dibutyl phthalate. The latter four van der Waals liquids obey isochronal superposition to a higher degree than the two hydrogen-bonded liquids. This is a prediction of the isomorph theory, and it confirms findings by other groups.

Abstract  Concentrations of nine phthalate diesters in 24-h airborne PM2.5 and PM10 were determined from October 2011 to August 2012 in a suburban area in Shanghai, China. Dimethyl phthalate (DMP), diethyl phthalate (DEP), di-n-butyl phthalate (DBP), di-iso-butyl phthalate (DIBP), benzyl butyl phthalate (BzBP), and di(2-ethylhexyl) phthalate (DEHP) were frequently detected in airborne particulate matter at sum concentrations of these six compounds ranging from 13.3 to 186ng/m(3), with an average value of 59.8ng/m(3) in PM2.5, and from 10.1 to 445ng/m(3), with an average value of 132ng/m(3) in PM10. DEHP, DBP, and DIBP were the major phthalate diesters found in PM samples. DEHP was found predominantly in coarse (size fraction of between PM2.5 and PM10) particles, whereas DMP, DEP, DBP, DIBP, and BzBP were found predominantly in fine (PM2.5) particles. The concentrations of phthalates in PM during warm months (207ng/m(3) for PM10 and 71.9ng/m(3) for PM2.5, on average) were significantly higher than those during cold months (76.9ng/m(3) for PM10 and 50.4ng/m(3) for PM2.5). Significant positive correlations were found between concentrations of total phthalates, DEHP, and BzBP, with the total mass and organic carbon content of PM. Based on the concentrations of DEHP, incremental lifetime cancer risks (ILCR) from inhalation exposure were estimated using a Monte Carlo simulation. Although the 95% probabilities for the ILCR values for the general population were below the U.S. Environmental Protection Agency (EPA) threshold of 10(-6), our result is an underestimate of the actual health risk because we only considered the outdoor inhalation exposure to DEHP in this study.

Abstract  BIOSIS COPYRIGHT: BIOL ABS. Some data on a newly developed filter/sorbent indoor air SVOC sampling device for thermal desorption analysis are described. Thermal desorption of SVOCs spiked on Tenax had response factors identical to on-column injection except for highly polar compounds like fatty acids. SVOCs spiked on quartz fiber filters had for non-oxygen compounds). Low nanogram on-tube amounts of lower desorption efficiency. In addition, it was indicated that the "memory" effect was an important source of background contaminations that might impair analysis of low nanogram on-tube amounts of some SVOCs. Polar SVOCs in the gas phase appear to adsorb to the quartz fiber filters. This functions as a precleaning of the sample and thus minimizes the problem with coeluting peaks. The relative standard deviations of air concentrations of 10 SVOCs in an office estimated from nine duplicate samples appeared to be sufficiently low to distinguish a day to day variation.

Abstract  The contamination and distribution of phthalate esters - synthetic compounds widely used in plastic product production, including food and medical packaging - has raised safety concerns due to their endocrine-disrupting activity and mandated to be treated. Bacillus subtilis strain 3C3, isolated as an organic-solvent-tolerant bacterium, was capable of utilizing diethyl phthalate as a sole carbon source. Biodegradation of diethyl phthalate occurred constitutively without lag period, and its kinetics followed a first-order model. The biodegradability was significantly enhanced with the supplementation of yeast extract as a co-metabolic substrate. In the presence of Tween-80 as a solubilizing agent, cells rapidly degrade a range of short-chain phthalate esters at high concentrations (up to 1000 mg l super(-1 for diethyl phthalate). The biodegradation of short-chain phthalates in the binary, ternary and quaternary substrate system revealed that the coexistence of other short-chain phthalates had no significant influence on the biodegradation of diethyl phthalate, and vice versa. These results substantiated that B. subtilis strain 3C3 has potential application as a bioaugmented bacterial culture for bioremediation of phthalates.)

Abstract  The equilibrium partitioning (EqP) method has been applied to establish sediment quality criteria (SQC); however, it does not consider the nonlinear irreversible sorption of many organic contaminants. In this research, the sorption and desorption of two phthalate esters (PAEs), dimethyl phthalate (DMP) and di(2-ethylhexyl) phthalate (DEHP), in four natural sediments collected from the Yangtze River and the Yellow River were studied; the impact of irreversible sorption of DMP and DEHP on SQC has been evaluated. Based on the reversible and irreversible biphasic sorption model, the values of maximum irreversible sorption capacity (q(max)(irr)) were 125.19 μg g(-1)-337.37 μg g(-1) for DMP and 515.87 μg g(-1)-591.40 μg g(-1) for DEHP. The q(max)(irr) value was positively related to the organic carbon and black carbon contents, cation exchange capacity, and surface area of the sediments. The values of the irreversible sorption coefficient K(oc)(irr) for both DEHP and DMP in the four sediments approximated to a constant of 10(6.46 ± 0.38), which was 1-2 orders of magnitude higher than their reversible sorption coefficient K(oc)(irr). The values of SQC for PAEs based on the EqP method were modified by involving the irreversible sorption. The modified SQC of DEHP could be 2 to 20 times higher than the value predicted by the EqP method, and the assessment results for DEHP contamination in the sediments with the modified SQC were more reasonable than those with the non-modified SQC. It indicated that the current SQC based on the EqP method may be unnecessarily strict for specific organic compounds and the irreversible sorption should be taken into account.

Abstract  A yeast-based assay was used to estimate the estrogenic potential of phthalate esters. The yeast transformants contained human-estrogen receptor alpha gene along with the estrogenic responsive elements upstream of beta -galactosidase reporter gene. Five phthalate esters were added to yeast cultures in doses ranging from 1.0x10(-3)~1.0x10(-11) mol/L and following incubation, the yeasts were then lysed and assayed for beta -galactosidase activity. Relative potency ratios were calculated and used to compare the estrogenic activity of five phthalate esters along with beta -galactosidase activity. Results showed that diethyl phthalate (DEP, 1x10(-7)~1x10(-9) mol/L), dibutyl phthalate (DBP, 1x10(-6)~1x10(-9) mol/L and BBP, 1x10(-3)~1x10(-6) mol/L show obviously estrogenic activity while dimethyl phthalate (DMP) and di-sec-octyl phthalate (DOP) do not. Relative potency ratios of DEP, DBP and BBP were 8.85x10(-2), 2.54x10(-2) and 8.82x10(-6) respectively, suggesting that DEP and DBP showed higher estrogenic activity than BBP. However, the maximum beta -galactosidase activity induced by BBP was the same as DEP, but higher than DBP. Although the classical nuclear estrogen receptors pathway hypothesis was accepted for decades, other rapid signal transductional pathways have been found recently. The yeast-based assay was only used for primary screening, it is strongly recommended to use other ways to explore estrogenic activity for chemicals.

Abstract  The aim of the current work was the design and evaluation of etodolac controlled porosity osmotic pump (CPOP) tablets exhibiting zero-order release kinetics. Variables influencing the design of (1) core tablets viz., (a) osmogent type (sodium chloride, potassium chloride, mannitol, and fructose) and (b) drug/osmogent ratio (1:0.25, 1:0.50, and 1:0.75), and (2) CPOP tablets viz., (a) coating solution composition, (b) weight gain percentage (1-5%, w/w), and (c) pore former concentration (5%, 10%, and 20%, v/v), were investigated. Statistical analysis and kinetic modeling of drug release data were estimated. Fructose-containing core tablets showed significantly (P < 0.05) more retarded drug release rates. An inverse correlation was observed between drug/fructose ratio and drug release rate. Coating of the optimum core tablets (F4) with a mixture of cellulose acetate solution (3%, w/v), diethyl phthalate, and polyethylene glycol 400 (85:10:5, v/v, respectively) till a 4% w/w weight gain enabled zero-order sustained drug delivery over 24 h. Scanning electron microscopy micrographs of coating membrane confirmed pore formation upon contact with dissolution medium. When compared to the commercial immediate-release Napilac® capsules, the optimum CPOP tablets (F4-34) provided enhanced bioavailability and extended duration of effective etodolac plasma concentration with minimum expected potential for side effects in healthy volunteers.

Abstract  In this study, to examine the mechanism of diethyl phthalate toxicity to cells, the effects of diethyl phthalate on apoptosis in a PC12 cell system were investigated by assaying apoptotic factors such as caspase-3, Bax, cytochrome c and DNA damage. Diethyl phthalate was shown to enhance the apoptosis induced by serum deprivation according to the results of DNA electrophoresis and TUNEL signal assays, although it could not induce apoptosis itself in the cells. This enhancement was thought to be because of an increase in caspase-3-like activity. In addition, the expression of bax and contents of cytochrome c in the cytosol showed a tendency to increase the cells exposed to diethyl phthalate. These results indicated that diethyl phthalate, a potential endocrine disrupter, affects the apoptotic system in PC12 cells. Diethyl phthalate may enhance oxidative stress such as that induced by reactive oxygen species in PC12 cells.

Abstract  A method based on liquid-liquid extraction (LLE) and automated large volume injection (LVI)GC-MS analysis was developed for the trace determination of phthalate di-esters in water samples at sub-mu g L-1 (ppb) levels. Strategies applied to reduce contamination include (i) careful selection of tools, glassware and solvents, (ii) systematic blank checks of the chromatographic system, glassware and solvents and (iii) frequent verifications of blanks during sequences. Background levels could be reduced to those present in the extraction solvent. For phthalates not present in the extraction solvent the limits of quantitation (LOQ) are 6 ng L-1 for di-methyl phthalate (DMP), 3 ng L-1 for benzylbutyl phthalate (BzBP) and 45 ng L-1 for the isomeric phthalate mixtures di-isononyl phthalate (DiNP) and di-isodecyl phthalate (DOP). For the other phthalates, the LOQ was set at twice the blank (extraction solvent) level and are 20 ng L-1 for di-ethyl phthalate (DEP), 60 ng L-1 for di-isobutyl phthalate (DiBP), 80 ng L-1 for di-n-butyl phthalate (DBP) and 30 ng L-1 for bis-(2-ethylhexyl) phthalate (DEHP).

Abstract  An i.r. study of MgCl2 supported TiCl4 Ziegler-Natta catalysts for propylene polymerization using Lewis base modifiers has been carried out. Two series of catalysts were prepared, differing mainly by the method used to prepare the MgCl2 support. One was prepared by precipitation and the other by ball-milling. Four different Lewis bases, of which two are diesters (di-2-ethyl phthalate and diisobutyl phthalate) and two are monoesters (ethyl benzoate and 2-ethyl hexyl benzoate), were employed. The i.r. investigation of the catalyst was focused on the identification of complexes formed. It was found that the diester-containing catalysts contain significant amounts of TiCl4 . diester complexes and phthaloyl mono- and di-chlorides complexed to MgCl2, whereas the monoester-containing catalysts are virtually free of these compounds. The chlorides are believed to be formed from the reaction of TiCl4 and diester weakly bonded to MgCl2. The TiCl4 . monoester complex is relatively weak so that the coordination of monoester with MgCl2 is much more favorable. The effects of the complexes, particularly their relative amounts, on the catalyst activity was investigated by carrying out propylene polymerizations with catalysts prepared by precipitation and by ball-milling method at three different activation temperatures.

Abstract  HEEP COPYRIGHT: BIOL ABS. A comprehensive quality assurance program was applied to the analysis of phthalate esters in sediment. By utilizing the rapid ultrasonic extraction of dried sediment and the detecton capabilities of selected ion monitoring mass spectrometry, the analytical scheme was simplified to reduce systematic errors due to contamination and to improve recoveries. Matrix blank levels were 2.5 ng in 5 g dry samples, and spiked field sample recoveries were 90%. Identification of different phthalate species was accomplished by multiple ion monitoring of characteristic ion fragments and retention time comparisons. Eleven phthalate species were measured in representative samples from various sites in the Chesapeake Bay and Chester River, Maryland (USA).

Abstract  A novel method for separating and enriching trace phthalate esters (PAEs) in river water by solvent sublation and their determination by high-performance liquid chromatography (HPLC) has been developed. The optimal conditions of the solvent sublation were obtained, that is n-hexane as the sublation solvent, pH 7 of the solution, a nitrogen flow rate of 70 mL min... and sublation time of 70 min. The floated product under the optimal conditions was determined by HPLC. In the process of HPLC analysis, an Eclipse XDB-C18 chromatographic column was used, and mobile phase consisted of acetonitrile and water using gradient elution, and the flow rate was 1.00 mL min.... The proposed method was applied to determine eight PAEs in the river water from Fangshan District, Beijing; the recoveries ranged from 76.9 to 120.4%, RSD values from 2.63 to 9.71%, and limit of detection values ranged from 0.001 (for diethyl phthalate and butyl benzyl phthalate) to 0.225 ...gL... (for dimethyl phthalate and dicyclohexyl phthalate). (ProQuest: ... denotes formulae/symbols omitted.)

Abstract  The ethylene-vinyl acetate (EVA) matrix containing furosemide was prepared by the casting method and the release patterns were observed. The solubility of furosemide was determined as a function of volume fraction of polyethylene glycol 400. The release of drug from the matrix was studied as a function of temperature and drug concentration. Plasticizers such as the citrates and the phthalates were added for preparing the membrane to increase the flexibility of the EVA matrix. The solubility of furosemide was the highest when the concentration of PEG 400 was 40% (v/v). The release rate of drug from the EVA matrix increased with increasing temperature and drug loading doses. A linear relationship was found between the release rate and the square root of the loading dose. The activation energy (Ea), which was measured from the slope of the logP versus 1000/T plots, was 12.33 kcal/mol for the 0.5% loading dose, and 11.58 kcal/mol for the 1.0% loading dose, and 11.00 kcal/mol for the 1.5% loading dose. Among the plasticizers used such as the citrates and the phthalates groups, diethyl phthalate showed the best enhancing effects in drug release. In conclusion, the application of an EVA matrix containing a plasticizer might be useful in the development of a controlled drug delivery system.