Polyoxyethylene alkyl esters

Citric acid Acidifier Polyoxyethylene alkyl esters Surfactant... 

Surfactants Nonionic Sorbitan esters Polysorbates Polyoxyethylene alkyl ethers Polyoxyethylene alkyl esters Polyoxyethylene aryl ethers Glycerol esters Cholesterol Anionic Sodium dodecyl sulphate Cationic Cetrimide Benzalkonium chloride... 

X — X polyoxyethylene sorbitan monolaurate — polyoxyethylene sorbitan monopalmitate O—O polyoxyethylene sorbitan monostearate (b) The effect of polyoxyethylene alkyl esters and ethers on the rectal absorption of non-ionized sulphisoxazole at pH 3.3. 

The most common surfactants for analytical applications are nonionic (polyoxyethylene glycol monoethers, polyoxyethylene methyl- -alkyl ethers, t-octylphenoxy polyoxyethylene ethers, and polyoxyethylene sorbitan esters... 

Occlusion is a condition that could affect drug transport from niosomes and through the stratum corneum. Such an effect was reported for saturated estradiol niosomal formulations composed of polyoxyethylene alkyl ether surfactants and sucrose ester surfactants with cholesterol and dicetyl phosphate, for which occlusion enhanced the drug human stratum corneum transport [43]. 

Skin safety of niosomes was tested in a number of studies. As an example, the toxicity of polyoxyethylene alkyl ether vesicles containing Ci2-i8 alkyl chains and 3 and 7 oxyethylene units was assessed by measuring the effect on proliferation of cultured human keratinocytes [47]. It was found that the length of either polyoxyethylene headgroup or alkyl chain had only a minor influence on keratinocyte proliferation. However, the ether surfactants were much more toxic than esters tested in this study. The concentrations of ether surfactants required to inhibit cell proliferation by 50% were 10-fold lower than for ester surfactants. Neither the HLB nor the critical micelle concentration values or cholesterol content affected keratinocyte proliferation. 

Vineland, NJ) or over-the-counter cosmetic creams promoted for improved hydration (L Oreal, Paris and Dior, Paris). More recently, parenteral liposome formulations of amphotericin B, doxorubicin, and dau-norubicin have been approved and marketed (ABELCET, Elan, the Liposome Co., Inc, Princeton, NJ AmBisome and DaunoXome, Nexstar/Fujisawa, Deerfield Park, IL Amphotec and Doxil, Sequus/ Alza, Menlo Park, CA), with others on the horizon for applications in photodynamic therapy. Although the vast majority of liposome preparations are constructed from phospholipids, other nonphospholipid materials can be used either alone or in mixtures to form bilayer arrays. One such example is Amphotec, which utilizes sodium cholesteryl sulfate as the primary lipid. Other liposome forming materials may include but are not limited to fatty-acid compositions, ionized fatty acids, or fatty acyl amino acids, longchain fatty alcohols plus surfactants, ionized lysophospholipids or combinations, non-ionic or ionic surfactants and amphiphiles, alkyl maltosides, a-tocopherol esters, cholesterol esters, polyoxyethylene alkyl ethers, sorbitan alkyl esters, and polymerized phospholipid compositions. ° ... 

Polyoxyethylene alkyl ethers polyethylene oxide polyoxyethylene sorbitan fatty acid esters polyoxyethylene stearates suppository bases. 

Hydrophobic regions can be one or two small, well-defined blocks of pendant hydrophobic moieties in an otherwise water-soluble polymer (2-4). An example is a water-soluble sulfonated BAB triblock copolymer where B is hydrophobic f-butylstyrene and A is vinyltoluene (2). However, hydro-phobic regions can also be less well-defined as well as more numerous in a polymer molecule than is the case for a triblock copolymer (5-22). For example, pendant alkyl esters appear to have been randomly incorporated in styrene-maleic anhydride (5) and vinyl benzyl ether-styrene-maleic anhydride (6-ii) copolymers. Also, alkyl polyoxyethylene acrylate monomers can be copolymerized with acrylamide to yield copolymers with pendant hydrophobic chains (12-15). More recently it was found (16-22) that small amounts of water-insoluble monomers that are solubilized by surfactants into aqueous solutions of a hydrophilic monomer produce copolymers with pendant hydrophobic chains, but the size, number, and nature of the hydro-phobic regions has not been determined. 

Glucoside alkyl ethers Polyoxyethylene glycol octylphenol ethers Polyoxyethylene glycol alkylphenol ethers Glycerol alkyl esters... 

Hirofumi, N., Itsuo, H., Yuji, F. and Yuichi N., Method and manufacturing of fatty acid esters of polyoxyethylene alkyl ethers, US Patent 5374 750, to Lion Corporation (1994). 

A wide variety of this group of surfactants is commercially available. They include some of the Tritons (alkyl phenol additives, as far as they are non-ionic). Tweens (sorbitan fatty acid ester polyoxyethylene ethers). Spans (sorbitan fatty acid esters) and alkyl polyoxyethylenes (C Ej, where n and x stand for the number of CH2- or CH3-. and CHjO-groups in the hydrophobic and hydrophilic parts of the molecule, respectively). Given our interest in the fundamentals we shall emphasize only the last-mentioned group, and only when n and x are sharply defined emd the two moieties are either linear or branched in a defined way. Unless specified otherwise, there is an OH-group at the end of the E-chain. Notwithstanding the non-ionic nature of these molecules, micelles sometimes appear to cany a (low) charge probably caused by preferential uptake of ionic species. 

The enhancement of enantioselectivity cannot be an effect of solubility because water-soluble substrates gave enhanced activities but no enantioselectivity increase [54], Acylation of PPM ((2S,4S)-4-diphenylphosphino-2-diphenylphosphinomethyl-pyrrolidine) with the chlorocarbonic ester of alkyl polyoxyethylene ethers (Brij 4)... 

Surfactants are used to control cell size and structure. The most common surfactants are siloxane-oxyalkylene copolymers, polyoxyethylene sorbitan fatty acid esters, and the condensation products of ethylene oxide with castor oil and alkyl phenols. A commonly added additive is urea which is used as a formaldehyde scavenger. Very fine particle size inorganic fillers can be added to act as nucleating sites and to promote finer, more uniform cell structure, as well as increased compressive strength, but at a cost of higher density. 

The hydrophilic component of these molecules is a carboxylic group, as is the case in the soap molecule. In general, an aceto- or propiocarboxylic group is attached to the polyoxyethylene chain by an ether bond. The free alkylcarboxylic acids can be prepared from salts such as fatty acid soaps. In contrast to alkyl ether sulfates, alkyl ether carboxylates contain no ester bonds and therefore they are not susceptible to hydrolysis. 

A straight forward method involves a preparation after the Williamson synthesis, which does have some industrial application. In this, the OH end-group of the alkyl polyoxyethylene as starting material is converted by monochloroacetic acid and metallic sodium to form the ester carboxylate and sodium chloride. 

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