Surfactants polyoxyethylated nonionic

Several ehemical enhancers, such as sodium ethylenediaminetetraacetate and sodium taurocholate, oleic acid [37], polyoxyethylated nonionic surfactants, citric acid, and dihydroxy bile salts open the paracellular route, presumably by disruption of the intraeellular OJC funetion [37], The use of nitrie oxide is another approach [39], Moreover, manipulation of the cyclooxygenase pathway activities to trigger the release of eompounds like substance P may provide another means for altering colonic permeability [40],... 

Sakai, K., et al. 1986. Contribution of calcium ion sequestration by polyoxyethylated nonionic surfactants to the enhanced colonic absorption of p-aminobenzoic acid. J Pharm Sci 75 387. 

Jiao J (2008) Polyoxyethylated nonionic surfactants and their applications in topical ocular drug delivery. Adv Drug Deliv Rev 60 1663-1673... 

W.U. Malik and O.P. Jhamb, Critical micelle concentration of polyoxyethylated nonionic surfactants and the effect of additives, Kolloid Z.Z. Polym. 242 (1970) 1209-1211. 

The overall objective of this research was to evaluate the effects of cosolvent addition on the ability of an ethoxylated nonionic surfactant to recover PCE from a heterogeneous, 2-D system. The specific tasks of this work were to (a) quantify the PCE solubilization rate and capacity in the presence and absence of a representative cosolvent (EtOH) and (b) investigate the effects of EtOH addition on surfactant delivery, plume migration and PCE recovery in a 2-D, layered sand tank. A representative nonionic surfactant, polyoxyethylated (POE) (20) sorbitan monooleate (Tween 80), was selected for study because of its capacity to solubilize PCE ( 0.7 g PCE/g surf at 20°C) and relatively high interfacial tension with PCE (5 dynes/cm). EtOH was chosen as the representative cosolvent because of its relatively low density (p = 0.79 g/cm1) and regulatory acceptance. 

Rivera TM, Leone-Bay A, Paton DR, Leipold H, Baughman RA (1997) Oral delivery of heparin in combination with sodium N-[8-(2-hydroxybenzoyl) aminojcaprylate pharmacological considerations. Pharm Res 14 1830-1834 Sakai K, Kutsuna TM, Nishino T, Fujihara Y, Yata N (1986) Contribution of calcium ion sequestration by polyoxyethylated nonionic surfactants to the enhanced colonic absorption of p-aminobenzoic acid. J Pharm Sci 75 387-390 Sakai M, Imai T, Ohtake H, Azuma H, Otagiri M (1997) Effects of absorption enhancers on the transport of model compounds in Caco-2 cell monolayers assessment by confocal laser scanning microscopy. J Pharm Sci 86 779-785... 

The surface activity of a particular surfactant depends on the balance between its hydrophilic and hydrophobic properties. For the simplest case of a homologous series of surfactants, an increase in the length of the hydrocarbon chain as the series is ascended results in increased surface activity. Conversely, an increase in the hydrophilicity, which for polyoxyethylated nonionic surfactants may be effected by increasing the length of the ethylene oxide chain, results in a decreased surface activity. This latter effect is demonstrated by Fig. 6.4, from which it is noted that lengthening of the hydrophilic... 

The properties of the polyoxyethylated nonionic surfactants show a pronounced dependence on the length of the polyoxyethylene chain. An increase in the chain length confers... 

Non-ionic surfactants do not exhibit Krafft points. Rather the solubility of nonionic surfactants decreases with increasing temperature and the surfactants begin to lose their surface active properties above a transition temperature referred to as the cloud point. This occurs because above the cloud point a separate surfactant-rich phase of swollen micelles separates the transition is visible as a marked increase in dispersion turbidity. As a result, the foaming ability of, for example, polyoxyethyle-nated non-ionics, decreases sharply above their cloud points. The addition of electro-... 

C. Burger-Guerrisi and C. Tondre, Conductometric study of the interaction of 1 1 electrolytes with nonionic surfactant having short polyoxyethylated chains Methanolic solutions of H- and F-alkylated surfactants and oil/water microemulsions, J. Colloid Interface Sci., 1987, 116, 100. 

Nonionic surfactants such as polyoxyethylated fatty alcohols (such as Emul-phor ON-870 from GAP), alkyl phenyl polyethylene glycol ethers (such as the Tergitols from Union Carbide) and polyoxyethylated octylphenol may be used as protective colloids along with anionic surfactants or, in some cases, as emulsifiers in their own right. The block copolymers of polyoxyethylene and polyoxypropylene (Pluronics) solubilized vinyl acetate. Polymerization takes place at the interface of the surfactant-monomer droplet and the aqueous phase [151]. 

It can be seen from Table 6 that anionic, cationic, and nonionic surfactants have all been exploited in formulating microemulsions for materials synthesis. Anionic and nonionic surfactants appear to be the most popular types of surfactants, with Aerosol OT (AOT) and the polyoxyethylated alkylphenyl ether surfactants (e.g., NP-5) leading. Part of the attraction of AOT and the NP surfactants is related to the fact that they permit microemulsion formulation without the need for cosurfactants. Also, a large body of information is already available on the phase behavior and structure of AOT microemulsions [121], and this makes it convenient to work with this anionic surfactant. A unique advantage of the nonionic surfactants is the fact that their use does not involve the introduction of (potentially undesirable) counterions. The ability to alter the size of the hydrophilic (oxyethylene) groups and/or the hydrophobic (alkyl) groups provides additional flexibility in surfactant selection. 

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