Sorbitans ethers

Surfactants. The use of surfactants is greatly restricted in formulating ophthalmic solutions. The order of surfactant toxicity is anionic > cationic >> nonionic. Several nonionic surfactants are used in relatively low concentrations to aid in dispersing steroids in suspensions and to achieve or to improve solution clarity. Those principally used are the sorbitan ether esters of oleic acid (Polysorbate or Tween 20 and 80), polymers of oxyethylated octyl phenol (Tyloxapol), and polyoxyl 40 stearate. The lowest concentration possible is used to perform the desired function. Their effect on preservative efficacy and their possible binding by macromolecules must be taken into account, as well as their effect on ocular irritation. The use of surfactants as cosolvents for an ophthalmic solution of chloramphenicol has been described [271]. This com-... 

Etherification. Carbohydrates are involved in ether formation, both intramoleculady and intermoleculady (1,13). The cycHc ether, 1,4-sorbitan, an 1,4-anhydroalditol, has already been mentioned. 3,6-Anhydro-a-D-galactopyranosyl units are principal monomer units of the carrageenans. Methyl, ethyl, carboxymethyl, hydroxyethyl, and hydroxypropyl ethers of cellulose (qv) are all commercial materials. The principal starch ethers are the hydroxyethyl and hydroxypropylethers (see Cellulose ethers Starch). 

Sorbitan esters of fatty acids are well known. Similar products can be made from ether carboxylic acids and sorbitol without an acid catalyst with a good color [39]. The advantage of these products is that the hydrophilicity can be adjusted by the polyethylene glycol content in the ether carboxylic acid. 

The reaction product with monoethanolamine acts as a thickening agent [41,101] and with alcohols as an emollient [40]. Also reaction products with amino acids and oligo- or polypeptides for use in cosmetic formulations are known [43]. Sorbitan esters from ether carboxylates are described as emulsifiers or mild surfactants in cosmetic formulations [39] and alkyl ether carboxylic acid taurides as nonirritant anionic surfactants for cosmetic cleaners in particular [44]. Using unsaturated ether carboxylates it is possible to make viscous formulations based on combinations of unsaturated and saturated ether carboxylates [111]. Highly purified alkyl ether carboxylates based on alcohol ethoxylates with low free alcohol content have also been described [112]. 

Such a dispersant formulation for dispersing oil contains a mixture of a sorbitan monoester of an aliphatic monocarboxylic acid, a polyoxyethylene adduct of a sorbitant monoester of an aliphatic monocarboxylic acid, a water-dispersible salt of a dialkyl sulfosuccinate, a polyoxyethylene adduct of a sorbitan triester or a sorbital hexaester of an aliphatic monocarboxylic acid, and a propylene glycol ether as solvent [311,312]. 

Fatty Acid Esters. Defoamers that are more environmentally acceptable than convential products are based on fatty acid esters of hydroxy alcohols, such as sorbitan monooleate [1908] or sorbitan monolaurate in combination with diethylene glycol monobutyl ether as a cosolvent [451]. These defoamer compositions are as effective as conventional materials, for example, those based on acetylenic alcohols are less toxic, especially to marine organisms, and are readily biodegradable. The defoamer compositions are used in water-based hydrocarbon well fluids during oil/gas well drilling, completion, and workover, especially in marine conditions. 

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

Polyoxyethylene sorbitan trioleate (Tween 85) sugar ester (DK-F-110) tetraoxyethylene monodecyl ether (C10E4) polyoxyethylene-p-f-octyl phenol (Triton X-100) pentaethylene glycol dodecyl ether... 

In certain cases, cholesterol is required for vesicle formation. It is commonly accepted that the hydrophilic lipophilic balance (HLB) is a parameter that could indicate the vesicleforming potential of surfactants. For amphiphils such as sorbitan esters and alkyl ethers, low HLB values could predict vesicle formation [52,55]. However, niosomes were obtained from polysorbate 20 (HLB 16.7), a highly hydrophilic molecule, when cholesterol at an appropriate concentration was added to the amphiphil [44], In this case it could be assumed that a kind of amphiphilic complex with a lower HLB was responsible for the vesicle formation. An excellent review on the structure, characteristics, chemical composition, and mechanism of action of niosomes was published by Uchegbu and Vyas [41]. 

Polyoxyethylene sorbitan monolaurate Dodecyl ether of polyoxyethylene glycol Polyoxyethylene polyoxypropylene polyol Polyoxyethylene glycol 400 monolaurate Anionic surfactants... 

Sorbitan Monostearate occurs as an off white to tan colored, hard, waxy solid. It is a mixture of partial stearic and palmitic acid esters of sorbitol and its mono- and dianhydrides. It is manufactured by reacting edible commercial stearic acid (usually containing associated fatty acids, chiefly palmitic) with sorbitol. It is soluble at temperatures above its melting point in toluene, dioxane, ether, ethanol, methanol, and aniline. It is insoluble in cold water, and in mineral spirits and acetone, but is dispersible in warm water and soluble, with haze, above 50° in mineral oil and in ethyl acetate. 

Microemulsions were obtained using different types and concentrations of surfactant, cosurfactant, and styrene. An anionic surfactant, sodium dodecyl sulfate (C12H250SO3Na), and two types of nonionic surfactants, Emsorb 6916 (sorbitan monolaurate) and Neodol 91-5 (ethojqrlated alcohol), were used. The surfactant concentration was varied between 5 to 10% (w/w) for the anionic system and between 5 to 15% (w/w) for the nonionic systems. Either 2-pentanol or ethylene glycol monobutyl ether (butyl cellosolve, C4H90CH2CH20H) was used as the cosolvent with the anionic surfactant. The amount of cosurfactant used depended on the anionic surfactant concentration and varied form 12.5 to 25% (w/w). 

The chemicals may constitute a substantial portion of the finished textile. In many cases 10% or more of the fabric s final weight may derive from textile chemicals added to improve or enhance one or another of the fabric s properties. Representative raw materials employed for textile finishing applications are fatty alcohol ether sulfates, vinyl acetate-ethylene copolymers, hydrated alumina, alkylolamides, alkoxylates, chlorinated paraffins, alginates, sodium tripolyphosphates, sorbitan fatty acid esters, ethoxylated triglycerides, and silicones. 

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. ° ... 

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. 

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

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