Polyoxyethylene, alkylated

The addition of linear chained alkyl alcohols shifts the percolation of AOT microemulsions to higher temperature, whereas the opposite effect is obtained by adding polyoxyethylene alkyl ethers [261]. 

Nonionic Polyoxyethylenated alkyl-phenols, alkylphenol ethoxylates Emulsifying agents Generally water-soluble Good chemical stability... 

Favretto and Tunis [198] extracted polyoxyethylene alkyl phenyl ethers as picrates into an organic solvent, complexed the polymer with sodium ion, and measured the absorption complex. This is one of the few specific methods available. 

Interactions of Nonionic Polyoxyethylene Alkyl and Aryl Ethers with Membranes and Other Biological Systems... 

It has been recognised for some time (see for example reference 1), that surfactants can increase the rate and extent of transport of solute molecules through biological membranes by fluidisation of the membrane. It is only recently, however, that sufficient work has been carried out to allow some analysis of structure-action relationships. In this overview an attempt is made, by reference to our own work and to work in the literature, to define those structural features in polyoxyethylene alkyl and aryl ethers which give rise to biological activity, especially as it is manifested in interactions with biomembranes and subsequent increase in the transport of drug molecules. 

Figure 4 Polyoxyethylene alkyl ether conformation a in aqueous solution, b in oil.

Polyoxyethylene alkyl ether and in particular decaoxyethylene oleyl ether CigHj5 (CH2CH20)io can be used as templating agent for silica mesoporous materials formation. The synthesis can be performed under both acidic or basic conditions with tetramethoxysilane (TMOS) as silica source while no mesoporous compound was obtained with sodium silicate. 

Phase diagrams of water, hydrocarbon, and nonionic surfactants (polyoxyethylene alkyl ethers) are presented, and their general features are related to the PIT value or HLB temperature. The pronounced solubilization changes in the isotropic liquid phases which have been observed in the HLB temperature range were limited to the association of the surfactant into micelles. The solubility of water in a liquid surfactant and the regions of liquid crystals obtained from water-surfactant interaction varied only slightly in the HLB temperature range. 

The behavior of a series of polyoxyethylene alkyl ether nonionic surfactants is also illustrative. According to Figure 11 the dioxyethylene (A) compound does not form liquid crystals when combined with water. Its solutions with decane dissolve water only in proportion to the amount of emulsifier. The tetraoxyethylene dodecyl ether (B) forms a lamellar liquid crystalline phase and is not soluble in water but is completely miscible with the hydrocarbon. The octaoxyethylene compound (C) is soluble in both water and in hydrocarbon and gives rise to three different liquid crystals a middle phase, an isotropic liquid crystal, and a lamellar phase containing less water. If the hydrocarbon p-xylene is replaced by hexadecane (D), a surfactant phase (L) and a lamellar phase containing higher amounts of hydrocarbon are formed in combination with the tetraoxyethylene compound (B-D). 

Citric acid Acidifier Polyoxyethylene alkyl esters Surfactant... 

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. 

Furthermore, aggregates of nonionic surfactants like polyoxyethylene alkyl/aryl ethers of the Tergitol, Triton, and Brij series were used as templates for the formation of mesoporous silica materials in neutral or acidic media. The pore diameters of the materials that can be obtained with these surfactants are restricted to around 5.5 nm. The advantages of these surfactants over triblock copolymers are that they are cheap, nontoxic, and biodegradable. An overview of the most commonly used SDAs is compiled in Table 3.1. 

No. 307 Polyoxyethylene alkyl ether (alkyl C = 12-15) (hereinafter referred to as AE)... 

Stability The technique and results of stability experiments were described explained in an earlier paper [I ]. In brief, a series of conunercially available homologous nonionic surfactants of the polyoxyethylene alkyl ether type and two nonionic surfactants were examined for their ability to affect the CMP process with respect to enhancing slurry stability. The salient features of the stability study are incorporated in the following discussion. 

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. ° ... 

Alkyl sulfates Quaternary ammonium compounds Polyoxyethylene alkyl-aryl ethers... 

Eccleston, G.M. Beattie, L. Microstructural changes during storage of systems containing cetostearyl alkohol/ polyoxyethylene alkyl ether surfactants. Drug Dev. Ind. Pharm. 1988, 14, 2499-2518. 

Eccleston GM, Beattie L. Microstructural changes during the storage of systems containing cetostearyl alcohol polyoxyethylene alkyl ether surfactants. In Rubinstein MH, ed. Pharmaceutical Technology Drug Stability. Chichester Ellis Horwood, 1989 76-87. 

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

The polyoxyethylene alkyl ethers are a series of polyoxyethylene glycol ethers of n-alcohols (lauryl, oleyl, myristyl, cetyl, and stearyl alcohol). Of the large number of different materials commercially available, four types are listed in the USPNF 23, one type in the JP 2001, and four types in the PhEur 2005. BP Macrogol cetostearyl ether... 

Polyoxyethylene alkyl ethers are employed extensively in cosmetics, where the CTFA names laureth-N, myreth-N, ceteth-N, and steareth-N are commonly used. In this nomenclature, N is the number of ethylene oxide groups, e.g. steareth-20. 

Polyoxyethylene alkyl ethers are nonionic surfactants produced by the polyethoxylation of linear fatty alcohols. Products tend to be mixtures of polymers of slightly varying molecular weights and the numbers used to describe polymer lengths are average values. 

Table I Synonyms of selected polyoxyethylene alkyl ethers.

Synonyms applicable to polyoxyethylene alkyl ethers are shown below. 

The polyoxyethylene alkyl ethers tend to be mixtures of polymers of slightly varying molecular weights, and the... 

Polyoxyethylene alkyl ethers are nonionic surfactants widely used in topical pharmaceutical formulations and cosmetics, primarily as emulsifying agents for water-in-oil and oil-in-water emulsions and the stabilization of microemulsions and multiple emulsions. 

Polyoxyethylene alkyl ethers have been used in formulation of oleosomes, hydrosomes, phosphosomes, vesicles and... 

Table II Pharmacopeial specifications for polyoxyethylene alkyl ethers.

---