Emulsion stabilizers polyethylene glycol

The stabilizing of aqueous latexes succeeded by using emulsifiers (anionic, nonionic) and/or their mixture, steric stabilizators (polyvinyl alcohol (PVOH), hydroxyethyl cellulose, polyethylene glycol, new protective colloids etc.), and polymerizable surfaces active agents, in general. Vinyl acetate (VAc) emulsion homopolymers and copolymers (latexes) are widely used as binders in water-based interior and exterior architectural paints, coatings, and adhesives, since they have higher mechanical and water resistance properties than the homopolymers of both monomers [2, 4, 7]. 

Wheeler, J. J., Wong, K. F., Ansell, S. M., et al. Polyethylene glycol modified phospholipids stabilize emulsions prepared from triacylglycerol. Pharm. Res. 83 1558-1564, 1994. 

It has been suggested, for example, that the addition of ethylene glycol and polyethylene glycols enhances the F/T stability of polymer emulsions (2). Further, the addition of electrolytes has been proposed to achieve the same goal (5). All are freezing-point depressants and may influence the other factors as well. 

Solution formulations, however, do not typically have these same constraints, and complexation provides an alternative to the use of non-aqueous solvents or large volumes. A few derivatized CDs (e.g., hydro-xypropyl and sulfobutyl ether) can be safely administered by parenteral routes. This is often where complexation and its improvements in aqueous solubility can be most readily utilized. The derivatized CDs often can be used to replace cosolvents such as ethanol, polyethylene glycol, and lipids, as well as provide an alternative to the use of emulsions and liposomes. The hydroxypropyl and sulfobutyl ether derivatives are stable in solution and can be readily autoclaved, often improving the heat stability of drugs. There are however, reports of complexation of CDs with anti-oxidants and preservatives " with both decreased and increased efficacy. ... 

Aqueous polyethylene glycol solutions can be used either as suspending agents or to adjust the viscosity and consistency of other suspending vehicles. When used in conjunction with other emulsifiers, polyethylene glycols can act as emulsion stabilizers. 

From this point of view, polyethylene glycol ethers of higher alcohols or alkylphenols like Neonol P1215-6 (oxo synthesis of higher alcohols C12—C15 with 6 EO) have a broader industrial basis. In addition to the 0x0 synthesis of higher alcohols C12—Cjs obtained by other methods can be used to obtain this type of surfactants. However, this type of products forms emulsions having a low coalescence stability and an aqueous serum is formed within few days. 

To improve the oral bioavailability of calcitonin, Garcia-Fuentes et al. used tripalmitate nanoparticles coated with chi-tosan or polyethylene glycol. The nanoparticles were prepared by a double emulsion solvent evaporation method that was adapted due to its high efficiency for the encapsulation of peptides. The nanoparticles were stabilized with soybean lecithin and the surface coating was done by incubation of the prepared lipid nanoparticles in a chitosan/poloxamer solution or by initial addition of PEG-stearate to the organic phase. Excess stabilizers were removed by centrifugation. Whereas... 

One of our designer materials is a CaP04-sheUed retrievable nanoreactor based on a DOPA-stabilized perfluorocarbon emulsion (see Table 15.1). Others include protein, polysaccharide, and polyethylene glycol-coated retrievable nanoreactors. Each contains a perfluoroocytlbromide core surrounded by one or more lipid stabilizers and a secondary coating (Table 15.1). 

Since the calculated free energy of interaction is largely dependent on the value chosen for Xi, then evidence of the effect of salts on Xi could lead to significant conclusions on the stability of emulsions in the presence of salts. Several reports of non-ionic surfactants and polyethylene glycols bear out the contention that electrolytes dehydrate the ethylene oxide chains and promote their salting out . This is what the study of the effect of NaCl and Nal referred to earlier (see Fig. 8.3) aimed to display-that salting in and salting out would have an effect on stability as predicted by Equation 8.30. 

The base polymer for this t5q>e of sealant exists in the form of an emulsion of micron- and submicron-sized partides of the polymer suspended in water. The base polymer formed by free radical polymerization may be a homopolymer of an acrylic monomer but is more likely to be a copolymer of a number of different monomers chosen to provide the correct balance of properties. The polymer latex has to be made more permanent and therefore a nonionic surfactant such as a nonyl phenol/ polyethylene oxide is added to help stabilize the emulsion. Other additives to the sealant formulation include plastid-zers, fillers, solvents, and silanes. A plasticizer is added to the formulation in order to improve upon or maintain the flexibility of the sealant. Solvents (usually a small amount) are added to improve the tooling of the sealant after it is applied. In addition, a solvent could be a material such as ethylene or propylene glycol which can improve the resistance of the packaged sealant to temperatures below freezing. The most widely used filler for this type of sealant is calcium carbonate. Silanes are often added to acrylics to improve the wet adhesion of the sealant to glass. Other additives include antimildew agents (for tub and tile applications) and clay for rheological control. 

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