Polyethylene Glycol activation

Components/ mechanism of action Light-activated polyethylene-glycol (PEG) polymer sealant for lung tissue. Monomeric (2-octyl cyanoacrylate) formulation tissue adhesive for skin closure. Bovine albumin cross-linked with gluteraldehyde tissue adhesive/sealant. 

Fig. 5. Light activation (arrow point.s to light wand) of polyethylene glycol (PEG) polymer on the surface of the lung as an adjunct to pneumostasis.

Polyethylene glycol (molecular weight, 300-6(W) can aid in the displacement of activated halogen by fluorine. Propionyl chloride is converted to propionyl fluoride with potassium fluoride and polyethylene glycol in acetonitrile [63] Treatment of benzyl chloride with a mixture of potassium fluoride and potassium iodide for 5 h in acetonitrile containing polyethylene glycol 200 gives benzyl fluoride in 62% yield [64],... 

The simplest way to prepare a biocatalyst for use in organic solvents and, at the same time, to adjust key parameters, such as pH, is its lyophilization or precipitation from aqueous solutions. These preparations, however, can undergo substrate diffusion limitations or prevent enzyme-substrate interaction because of protein-protein stacking. Enzyme lyophilization in the presence of lyoprotectants (polyethylene glycol, various sugars), ligands, and salts have often yielded preparations that are markedly more active than those obtained in the absence of additives [19]. Besides that, the addition of these ligands can also affect enzyme selectivity as follows. 

Adsorption on solid matrices, which improves (at optimal protein/support ratios) enzyme dispersion, reduces diffusion limitations and favors substrate access to individual enzyme molecules. Immobilized lipases with excellent activity and stability were obtained by entrapping the enzymes in hydrophobic sol-gel materials [20]. Finally, in order to minimize substrate diffusion limitations and maximize enzyme dispersion, various approaches have been attempted to solubilize the biocatalysts in organic solvents. The most widespread method is the one based on the covalent linking of the amphiphilic polymer polyethylene glycol (PEG) to enzyme molecules [21]. 

In our ongoing efforts to develop oxidation catalysts that are functional in water as environmentally berrign solvent, we synthesized a water-soluble pentadentate salen ligand with polyethylene glycol side chairts (8). After coordination of copper(II) ions to the salen ligand, a dinuclear copper(II) complex is obtained that is soluble in water, methanol and mixtures of both solvents. The aerobic oxidation of 3,5-di-tert.-butylcatechol (DTBC) into 3,5-di-terr.-butylqitinone (DTBQ) was used as a model reaction to determine the catalytically active species and initial data on its catalytic activity in 80% methanol. 

Acid-catalyzed matrices, kinetics of controlled release, 170-179 Active targeting, definition, 276 Adenosine deaminase, activity of polyethylene glycol modified enzymes, 98-99 Adjuvax... 

In this type of reaction the active drug undergoes decomposition following reaction with the solvent present. Usually the solvent is water, but sometimes the reaction may involve pharmaceutical cosolvents such as ethyl alcohol or polyethylene glycol. These solvents can act as nucleophiles, attacking the electropositive centers in drug molecules. The most common solvolysis reactions encountered in pharmaceuticals are those involving labile carbonyl compounds such as esters, lactones, and lactams (Table 1). 

The anhydrous petrolatum base may be made more miscible with water through the use of an anhydrous liquid lanolin derivative. Drugs can be incorporated into such a base in aqueous solution if desired. Poly-oxyl 40 stearate and polyethylene glycol 300 are used in an anti-infective ointment to solubilize the active principle in the base so that the ointment can be sterilized by aseptic filtration. The cosmetic-type bases, such as the oil-in-water (o/w) emulsion bases popular in dermatology, should not be used in the eye, nor should liquid emulsions, owing to the ocular irritation produced by the soaps and surfactants used to form the emulsion. 

In a similar fashion, polyethylene glycol can be activated with CDI for connection to a protein, as has been shown for superoxide dismutase, a2-macroglobulin, a2-macro-globulin-trypsin, lactoferrin, and tissue plasminogen activator t208] [209]... 

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