Ethylene-vinyl acetate matrix

Wheeler, R. G. Friel, P. G., Release of Drugs From IUD s Using an Ethylene / Vinyl Acetate Matrix, International Fertility Research Program, Research Triangle Park, NC, 1982. 

Kim J, Shin SC. Controlled release of atenolol from the ethylene-vinyl acetate matrix. Int J Pharm 2004 273(1-2) 23-27. 

Shin SC, Choi JS. Enhanced bioavailability of atenolol by transdermal administration of the ethylene-vinyl acetate matrix in rabbits. Eur J Pharm Biopharm 2003 56(3) 439-443. 

Shin SC, Lee HJ. Enhanced transdermal delivery of triprolidone from the ethylene-vinyl acetate matrix. Eur J Pharm Biopharm 2002 54(3) 325-328. 

Using field-based models, it is more difficult to provide information about the chain conformation on the surface however, attempts have been made to understand phase separation and mechanical properties of composites. Shou et al. combined SCF/DFT techniques with lattice spring model (LSM) to study the effects of the spatial distribution and aspect ratio of particles (rods and spheres) on the mechanical properties of the composite. Buxton and Balazs combined TDGL theory for polymer blends with BD for nanorods in the simulations of nanocomposites. i A percolating network of nanorods was identified in the minority phase of a bicontinuous structure. Clancy and Gates developed a hybrid model for CNTs in a bulk poly(ethylene vinyl acetate) matrix. Molecular structures of... 

Abstract. In this study various composites based on the commercial ethylene vinyl acetate polymer matrix and multiwalled carbon nanotubes were prepared by casting from solution in the form of thick films. The degree of dispergation of carbon nanotubes in the polymer matrix was examined by scanning electron microscopy. Electrical conductivity and mechanical properties of those composites were investigated. It was observed that the electrical conductivity of composites increases with an increase of multiwalled carbon nanotubes content. The mechanical properties of composites were only slightly changed when compared with properties of neat ethylene vinyl acetate matrix. 

Although current matrix diffusional systems are most suitable for small-molecule compounds, it has been demonstrated (84) that soHd hydrophobic polymers allow dispersed powdered macromolecules of nearly any size, for example, ethylene—vinyl acetate copolymers containing dispersed polypeptides, to be released for periods exceeding 100 days. 

Ethylene-vinyl acetate Fetterman [37] reinforced compounded ethylene-vinyl acetate (EVA) copolymer by using short hbers and found that silane coupling agents were effective at establishing improved hber-matrix adhesion. Das et al. [38] prepared carbon fiber-filled conductive composites based on EVA and studied the electromagnetic interference shielding effectiveness of the composites. 

The most current method of nitroglycerin application is a transdermal device or skin patch. A cross section of such a patch is illustrated in Figure 6. The patch is actually a multi-layered polymer stack. The semipermeable membrane which comes in contact with the skin is usually composed of an ethylene-vinyl acetate copolymer or polypropylene. The reservoir contains the drug in a hydrogel or polymer matrix or solvent (the material must be chosen to insure uniform delivery). Examples of some solvents used include dimethyl sulfoxide (DMSO), sodium lauryl sulfate (SDS - a detergent) and propylene glycol/oleic acid. 

Figure 12.14 Release of the antibiotic drug chloramphenicol dispersed in a matrix of poly(ethylene-vinyl acetate). The solid line is calculated from Equation (12.10) [21]...

Ethylene vinyl acetate copolymers are used as membranes and backings in laminated transdermal drug delivery systems. They can also be incorporated as components in backings in transdermal systems. Ethylene vinyl acetate copolymers have been shown to be an effective matrix and membrane for the controlled delivery of atenolol triprolidine, and furose-mide. The system for the controlled release of atenolol can be further developed using ethylene vinyl acetate copolymers and plasticizers. ... 

Figure 4. Cumulative release of bovine serum albumin vs. time. The matrix was made of ethylene-vinyl acetate copolymer and bovine serum albumin. Standard error of the mean of the cumulative release at each time point was within 12%.

Figure 2.3 IgG levels after administration of drug delivery systems in rats. Controlled-delivery systems for antibody class IgG. The insert figures show the release of antibody from the delivery system during incubation in buffered saline. The panel (a) inset shows release from poly(lactic acid) microspheres these spherical particles were 10-100/rm in diameter. The panel (b) inset shows release from a poly[ethylene-co-(vinyl acetate)] matrix these disk-shaped matrices were 1 cm in diameter and 1 mm thick. In both cases, molecules of IgG were dispersed throughout the solid polymer phase. Although the amount of IgG released during the initial 1-2 days is greater for the matrix, the delivery systems have released comparable amounts after day 5. (a) Comparison of plasma IgG levels after direct injection of IgG (open circles) or subcutaneous injection of the IgG-releasing polymeric microspheres characterized in the inset (filled circles). The delivery system produces sustained IgG concentrations in the blood [3]. (b) Comparison of plasma IgG levels after direct intracranial injection of IgG (open squares) or implantation of an IgG-releasing matrix (filled squares) [4]. The influence of the delivery is less dramatic in this situation, probably because the rate of IgG movement from the brain into the plasma controls the kinetics of the overall process.

Performance improvement of polysulfone ultrafiltration membrane has been achieved by blending with PANI-NFs [457]. Conducting blends of nanostruetured PANI and PANI-clay nanocomposites with ethylene vinyl acetate as host matrix have been prepared [458]. A new conducting hybrid biocompatible composite material of PANI-NFs well dispersed in a collagen matrix was fabricated with various PANI-NFs/eoUagen ratios [459]. PANI-NFs doped by protonic acids can be efficiently dispersed in vinylidene fluoride-trifluoroethylene copolymers [460]. Fabrication of MWCNTs/PANI-NF nanocomposites via electrostatic adsorption in aqueous colloids has been reported [143]. A PANI-NFs/ carbon paste electrode was prepared via dopping PANI-NFs into the carbon paste [461]. 

A large mrmber of polymeric materials are involved in a web coating. These include poly-virtylchloride, polyurethanes (thermoplastic and thermoset solvent-based and water-based), natural, nitrile, chloroprene, and ethylene-propylene rabbers, silicones, polyethylene (chlorinated and chlorositifonated), polyamide, polyester, acrylic resins, polyvinylal-cohol, polytetrafluroethylene, and ethylene-vinyl acetate copolymer as the main matrix polymers of coating compositions. Most of these polymers are not plasticized or seldom... 

In addition to frozen tissue sections, tissue blotting and laser-capture microdisection methodologies can also be used. In the former method, the proteins are transferred by blotting freshly dissected tissues onto an active Cig-coated surface. Another surface of choice for blotting is a carbon-filled polyethylene membrane. In the laser-capture microdisection method, a specific population of cells from a stained tissue is transferred onto an ethylene-vinyl acetate transfer film. A matrix is applied to the isolated cells through a narrow capillary. 

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