Ethylene oxide biological activity

Reduced nicotinamides are readily oxidized by PAN (31). Since the products form cyanide complexes with characteristic UV spectra and also react in a predictable fashion with specific dehydrogenases, they have been characterized as the biologically active oxidized forms of the coenzymes (31). A different reaction of PAN is with ethylenic double... 

A blended composition for facilitating delivery of a biologically active conjugated material was prepared by Kabanov [6] and consisted of a block copolymer of ethylene oxide and acrylic acid salt of cetylpyridinium bromide, (II). 

A block copolymer effective as a controlled release agents of biologically active materials have been prepared. This agent consisted of ethylene oxide-propylene sulfide-ethylene oxide teipolymer that had been end-capped with a selected cysteine-containing peptide. These materials resist degradation prior to reaching their intended targets because they behave as multilamellar vesicles. 

The trisaccharide chain in Cinerubin A, an anthracycline antibiotic with antimitotic activity, has been replaced by a poly(ethylene glycol) The resulting poly(ethylene oxide)-bound e-pyrromycinone is readily soluble in water and exhibits full biological activity. In this case, the hydrophilic poly(ethylene oxide) chain appears to be perfectly suitable to simulate the physicochemical properties of the oligosaccharide chain. 

The biological activity of ethylene oxide (EtO) was initially observed by Cotton and Roark,who detected it as an insecticide, in concentrations ranging from 3.2mgL to 32.0mgL In 1937, Gross and Dixon requested the patent of EtO as a sterilization method due to the considerable experimental evidences it presented. 

We obtained 7-oxoisodrimenin by oxidation of the keto diol (131) with an excess of PCC [92], On oxidation of (131) with Mn02 or PCC (2 mol. equivalents), a mixture of the semiacetals (132) and (133) and keto lactone (136) was obtained. One of these semiacetals, (133) was isolated by crystallization, and its structure and stereochemistry were confirmed by X-ray data [93]. The mixture of semiacetals (132) and (133) was further oxidised to the keto lactone (136). This lactone has no biological activity itself, but it has been used as an intermediate in the total synthesis of bioactive ( )-warburganal (16) [84]. The ethylene ketal (140) of the keto lactone (136) was converted into the keto diol (131), whose transformation to warburganal (16) was discussed above (Scheme 23). 

Biologically active molecules are sometimes trapped in PDMS when end-functionalized PDMS chains are linked into a network structure. This method has been done, for example, with a lipase enzyme. The PDMS plays a beneficial role as an activator or protective agent. Similar results were found for the enzyme a-chymotripsin, with some short-chain poly(ethylene oxide) used to enhance enzymatic activity. It is also possible to generate microtopographic patterns that affect Escherichia coU biofilm formation on PDMS surfaces. 

Some polymers such as poly(acrylic acid) or polyacrylamide precipitate from aqueous solutions when cooled (normal solubility behavior) whereas others such as poly(ethylene oxide), poly(propylene oxide), or poly(methacrylic acid) phase separate when heated (inverse solubility behavior). Solution turbidimetiy is often used to obtain plots of phase-separation temperatures termed cloud point vs concentration for fixed solvent conditions. Changes in ionic strength, molecular weight, and addition of co-solvents or structure breakers affect the shapes of phase behavior curves. The important conclusion of such studies is that the total free energy of the polymer and water must be considered to predict phase behavior. The structin-e and dynamics of water surroimding polynucleotides, proteins, polysaccharides, and lipids are also major determinants of biological activity (8-10). 

Polymers with which we will deal throughout this chapter are water soluble. They can be either ionic or nonionic. Some of them are synthetic, others are of biological origin (proteins, for instance). Both homopolymers and heteropolymers exist. Some polymers own amphiphilic monomers that induce surface-active properties to the whole polymeric structure. Water plays a very important role in determining the polymer properties in solution. The properties are also greatly modified by the addition of salts or by a pH modification. Frequently encountered nonionic polymers in polymer-surfactant interactions and their subsequent adsorption behavior at solid surfaces are poly(ethylene oxide) (PEO), poly(vinyl pyrrolidone) (PVP), polyacrylamide, and poly(vinyl alcohol). 

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