Polyoxyethylene polysorbate

E 434 Polyoxyethylene sorbitan monopahnitate (polysorbate 40) E 435 Polyoxyethylene sorbitan monostearate (polysorbate 60)... 

Polysorbates (polyoxyethylene sorbitan fatty acid esters, refer to Fig. 3) are a mixture of molecules of varying sizes rather than a uniform mixture of a single chemical entity. All four official polysorbates (numbers 20,40, 60, and 80), listed in U.S. Pharma-copeia/National Formulary (USP/NF), contain 20 moles of oxyethylene. Polysorbates... 

Non-ionic Polyoxyethylene alcohol Alkylphenol ethoxylate Polysorbate 80 w+x+y+z= 20, R=(C17H33)COO... 

The polysorbates used most regarding efflux pump inhibition are polyoxyethylene sorbitan monolaurates (Tween 20), polyoxyethylene sorbitan monopalmi-tates (Tween 40) and polyoxyethylene sorbitan monooleates (Tween 80). Various studies demonstrate the ability of polysorbates to inhibit efflux pumps. In transport experiments across intestinal mucosa, the efflux ratio (basolateral to apical drug transport/apical to basolateral drug transport) of rhodamine 123 was reduced in the presence of Tween 80 (Shono et al. 2004). In another study, Zhang et al. demonstrated enhanced absorption of the P-glycoprotein substrate digoxin in rats in the presence of Tween 80 (Zhang et al. 2003). 

Polyoxyethylene sorbitan monolaurate (Polysorbate 20 or Tween 20) 0 II CH20(CH Hfi)z1CH2CH20—C CH2(CH2)9CH3 I... 

Polysorbate 80 Solution Dissolve 25 g of polysorbate 80 (polyoxyethylene sorbitan monooleate) in ethyl alcohol, and dilute with ethyl alcohol to make 250 mL. 

Sorbitan fatty acid esters are produced by polymerization of ethylene oxide to sorbitan fatty acid esters. The resulting polyoxyethylene sorbitan esters are nonionic hydrophilic emulsifiers. They are used in bakery products as antistaling agents. They ate known as polysorbates with a number as indication of the type of fatty acid used (e.g., lauric, stearic, or oleic acid). 

Data on the effects of surfactants on the hydrolysis of aryl sulfate esters have become available only recently. A non-ionic heterodisperse polyoxyethylene sorbitan monooleate surfactant, Polysorbate 80, was found to increase the observed rate constant for the acid-catalyzed hydrolysis of potassium 2,4-dichloronaphthyl sulfate by a factor of 16-3 at a surfactant concentration of 8 g/1, but an additional 5-fold increase... 

Tween 80 (also known as At-Plus 109 and Polysorbate 80) is a polyoxyethylene sorbitan monooleate and was obtained from Atlas Chemical Industries, Inc. This nonionic surfactant has an HLB (hydrophile-lipophile balance) of 15.0 and is used as an emulsifier, solubilizer, and dispersant. It was used without further purification at the 0.1% (w/v) level in partitioning and greenhouse herbicidal evaluations as described below. 

Surfactant. Polyoxyethylene (20) sorbitan monooleate (also known as Tween 80, At-Plus 109, or Polysorbate 80) was obtained from Atlas Chemical Industries and used as received. It was used at the 0.1% (w/v) concentration level in all herbicidal activity evaluations and partitioning studies requiring the use of surfactant. 

Buffers can also be provided in parenteral formulations to ensure the required pH needed for solubility and/or stability considerations. Other excipients included in parenteral products are preservatives (e.g., benzyl alcohol, p-hydroxybenzoate esters, and phenol), antioxidants (e.g., ascorbic acid, sodium bisulfite, sodium metabisulfite, cysteine, and butyl hydroxy anisole), surfactants (e.g., polyoxyethylene sorbitan monooleate), and emulsifying agents (e.g., polysorbates). An inert gas (such as nitrogen) can also be used to enhance drug stability. Stability and solubility can also be enhanced by the addition of complexation and chelating agents such as the ethylenediaminetetraacetic acid salts. For a more detailed list of approved excipients in parenteral products, the reader should consult the monographs within the USP. 

Polyoxyethylene-9-lauryl ether (laureth-9), Brij 35, Brij 96, polysorbate 80, quillaja saponin, dodecylmaltoside Na glycocholate, Na taurocholate, Na deoxycholate,... 

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. 

Polysorbates are surfactants that are pegylated derivatives of sorbitan monoesters (i.e., monolaurate, monopalmitate, monostearate, monooleate, or monoisostearate) or sorbitan triesters (i.e., tristearate or trioleate) and are available in many grades. Poly-sorbate 80, also known as Tween 80, is a mixture of polyoxyethylene 20 sorbitan monooleates and is a yellow viscous liquid at room temperature. Sorbitan monooleate, also known as Span 80, is a yellow viscous... 

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