Polyoxyethylene stearate

SYNS POLYOXYETHYLENE-8-MONOSTEARATE POLYOXYETHYLENE(8)STEARATE TRYDET SA SERIES... 

Polyoxyethylene stearates are nonionic surfactants produced by polyethoxylation of stearic acid. Two systems of nomenclature are used for these materials. The number 8 in the names poloxyl 8 stearate or polyoxyethylene 8 stearate refers to the approximate polymer length in oxyethylene units. 

Gluten was obtained from ProVim, a gluten-enriched flour, by a conventional dough-and-wash procedure (16). Gliadin was separated from the gluten by the method of Jones et al. (17). The surfactants selected for study were Myrj 45 [polyoxyethylene (8) stearate], Tween 60 [polyoxyethylene (20) sorbitan monostearate], Brij 35 [polyoxyethylene (23) lauryl ether], Brij 76 [polyoxyethylene (10) stearyl ether], Brij 78 [polyoxyethylene (20) stearyl ether], and calcium stearoyl-2-lactylate. (Note that the numbers in parentheses indicate the number of monomer units of ethylene oxide.) Working solutions were made up in 70% ethanol at 2.5 mg per 100 ml solution. 

W. C. Hueper and W. W. Payne, Polyoxyethylene(8)-stearate Carcinogenic studies, Arch. Environ. Health 6, 484-494 (1963). 

Some studies reported that polyoxyethylene (POE) stearates (under the brand name Myrj) and alkyl-polyethyleneoxide (PEO) surfactants (under the brand name Brij) can inhibit efflux pumps. The oral bioavailability of the P-gp substrate cyclosporine A administered in a solid dispersion of polyoxyethylene 40 stearate (Myrj 52) was in the same range as the oral bioavailability of the commercial product Sandimmune Neoral (Liu et al. 2006). In a study by Lo, it has been shown that apical to basolateral epirubicin transport across Caco-2 cells was enhanced in the presence of polyoxyethylene 40 stearate and the basolateral to apical transport was decreased. These results indicate that polyoxyethylene stearates effect efflux pumps (Lo 2003). Similar results were gained when using polyoxyethylene laurylether (Brij 30). In another study, tablets based on polyoxyethylene 40 stearate containing the P-gp substrate rhodamine 123 increased the oral bioavailability in rats by about 2.4-fold (Foger et al. 2006a). 

Solid-Lipid Nanoparticles SLNs have been used to deliver small molecules and macromolecules such as DNA and peptides. The in vitro and in vivo applications of SLNs are reviewed elsewhere [125,126]. The stability and oral bioavailability of insulin were enhanced when administered in wheat germ agglutinin-conjugated nanoparticles [127], A polyoxyethylene stearate coat on the SLN confers stealth properties [128],... 

Surfactants Polyoxyethylene stearate, Renex, Poloxamer 188, Texafor AIP, deoxycholic acid. Tweens, Spans Miscellaneous Pentaerythritol, pentaerythrityltetracetate, urea, urethane, hydroxyalkylxanthins. 

Materials that are solubilized in polyethylene glycol can be solubilized in the polyoxyethylene chains on the surface of a nonionic micelle. Ismail, Gouda, and Motawi found that the micellar partition coefficients of barbiturates in polysorbates 20, 40, 60, and 80 is a function of the solute substituents and is proportional to the octanol-water partition coefficient of the barbiturate. Similarly, Ikeda, Kato, and Tukamoto showed that the solubilization of alkyl barbiturates by polyoxyethylene lauryl ether is not dependent upon the number of carbons in the substituents. Since the different polysorbates contain different aliphatic groups, the rather small dependence of solubilization upon polysorbate number (i.e., upon alkyl chain length) suggests that the barbiturates are not solubilized primarily in the hydrocarbon portion of the micelle. Gouda, Ismail, and Motawi showed that the solubilization of barbiturates in polyoxyethylene stearates is proportional to the number of polyoxyethylene units in the surfactant. 

Several non-ionic surface-active materials have been developed as suppositories vehicles. Many of these bases, known as water-dispersible bases, can be used for the formulation of both water-soluble and oil-soluble drugs. The surfactants most commonly used are thepolyoxyethylene sorbitan fatty acid esters (Tweens), the polyoxyethylene stearates, and the sorbitan fatty acidesters (Spans). These surfactants may be used alone, blended, or with other suppository base materials to yield a wide range of melting points and consistencies. 

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

The polyoxyethylene stearates are a series of polyethoxylated derivatives of stearic acid. Of the large number of different materials commercially available, one type is listed in the USPNF 23. 

For synonyms applicable to specific polyoxyethylene stearates, see Table I. 

Table I Synonyms of selected polyoxyethylene stearates and distearates.

Table II Empirical formulas and molecular weights of selected polyoxyethylene stearates.

In both structures, R represents the alkyl group of the parent fatty acid. With stearic acid, R is CH3(CH2)i6- However, it should be noted that stearic acid usually contains other fatty acids, primarily palmitic acid, and consequently a polyoxyethylene stearate may also contain varying amounts of other fatty acid derivatives such as palmitates. 

Polyoxyethylene stearates are generally used as emulsifiers in oil-in-water-type creams and lotions. Their hydrophilicity or lipophilicity depends on the number of ethylene oxide units present the larger the number, the greater the hydrophilic properties. Polyoxyl 40 stearate has been used as an emulsifying agent in intravenous infusions. ... 

Polyoxyethylene stearates are particularly useful as emulsifying agents when astringent salts or other strong electrolytes are present. They can also be blended with other surfactants to obtain any hydrophilic-lipophilic balance for lotions or ointment formulations. See Table III. 

Although polyoxyethylene stearates are primarily used as emulsifying agents in topical pharmaceutical formulations, certain materials, particularly polyoxyl 40 stearate, have also been used in intravenous injections and oral preparations. 

Polyoxyethylene stearates have been tested extensively for toxicity in animals and are widely used in pharmaceutical formulations and cosmetics. They are generally regarded as essentially nontoxic and nonirritant materials. 

Polyoxyethylene stearates are generally stable in the presence of electrolytes and weak acids or bases. Strong acids and bases can cause gradual hydrolysis and saponification. 

Polyoxyethylene stearates that contain greater than 100 ppm of free ethylene oxide may present an explosion hazard when stored in a closed container. This is due to the release of ethylene oxide into the container headspace, where it can accumulate and so exceed the explosion limit. 

Polyoxyethylene stearates are unstable in hot alkaline solutions owing to hydrolysis, and will also saponify with strong acids or bases. Discoloration or precipitation can occur with salicylates, phenolic substances, iodine salts, and salts of bismuth, silver, and tannins.Complex formation with preservatives may also occur. The antimicrobial activity of some materials such as bacitracin, chloramphenicol, phenoxymethylpenicillin, sodium penicillin, and tetracycline may be reduced in the presence of polyoxyethylene stearate concentrations greater than 5% w/w. ... 

Polyoxyethylene stearates are prepared by the direct reaction of fatty acids, particularly stearic acid, with ethylene oxide. 

Thoma K, Ullmann E, Fickel O. The antibacterial activity of phenols in the presence of polyoxyethylene stearates and polyethylene glycols [in German]. Arch Pharm 1970 303 289— 296. 

Ullmann E, Moser B. Effect of polyoxyethylene stearates on the antibacterial activity of antibiotics [in German]. Arch Pharm 1962 295 136-143. 

Calcium stearate magnesium stearate polyoxyethylene stearates purified stearic acid zinc stearate. 

A relationship between the lipophilicity of the solubilisate, expressed by the partition coefficient between octanol and water, Poctanoi (see Chapter 5), and its extent of solubilisation has been noted for the soluhilisation of substituted barbituric acids by polyoxyethylene stearates, of substituted benzoic acids by polysorbate 20, and of several steroids by polyoxyethylene nonionic surfactants. An exhaustive survey of data for the solubilisation of some 64 dmgs by bile salt micelles revealed linear relationships between log (partition coefficient between micelles and water) and log Poctanoi ach of seven bile salts... 

Name Glycerol monostearate and Polyoxyethylene stearate Sample preparation Potassium bromide dispersion 1 mg / 300 mg... 

---