Polyoxyethylene Alkyl Ethers

Synonyms: 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

Description: Polyoxyethylene alkyl ethers vary considerably in their physical appearance from liquids, to pastes, to solid waxy substances. They are colorless, white, cream-colored or pale yellow materials with a slight odor.

Chemical Name: Polyethylene glycol monocetyl ether 
Polyethylene glycol monolauryl ether 
Polyethylene glycol monooleyl ether 
Polyethylene glycol monostearyl ether 

Emulsifying agent; penetration enhancer; solubilizing agent; wetting agent.

• 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 are used as solubilizing agents for essential oils, perfumery chemicals, vitamin oils, and drugs of lowwater solubility such as cortisone acetate, griseofulvin, menadione, chlordiazepoxide and cholesterol

• They have applications as antidusting agents for powders; wetting and dispersing agents for coarse-particle liquid dispersions; and detergents, especially in shampoos, face washes and similar cosmetic cleaning preparations.

• They are used as gelling and foaming agents (e.g. Brij 72 gives a quick-breaking foam, while Brij 97 (15–20%), Volpo N series and Cremophor A25 (21–30%) give clear gels).

• Polyoxyethylene alkyl ethers have also been used in suppository formulations to increase the drug release from the suppository bases.

• Polyoxyethylene alkyl ethers (especially laureth-23) have been used as a solubilizer and coating agent to provide hydrophilicity to polymeric nanoparticles.

• Polyoxyethylene alkyl ethers such as polidocanol are suitable for use in injectable formulations as a solubilizer or dispersant.

Discoloration or precipitation may occur with iodides, mercury salts, phenolic substances, salicylates, sulfonamides, and tannins.

Polyoxyethylene alkyl ethers are also incompatible with benzocaine, tretinoin and oxidizable drugs.

The antimicrobial efficacy of some phenolic preservatives, such as the parabens, is reduced owing to hydrogen bonding.

Cloud points are similarly depressed by phenols owing to hydrogen bonding between ether oxygen atoms and phenolic hydroxyl groups.

Salts, other than nitrates, iodides, and thiocyanates (which cause an increase) can also depress cloud points.

Polyoxyethylene alkyl ethers are used as nonionic surfactants in a variety of topical pharmaceutical formulations and cosmetics. The polyoxyethylene alkyl ethers form a series of materials with varying physical properties; manufacturers’ literature should be consulted for information on the applications and safety of specific materials. Although generally regarded as essentially nontoxic and nonirritant materials, some polyoxyethylene alkyl ethers, particularly when used in high concentration (>20%), appear to have a greater irritant potential than others. Animal toxicity studies suggest that polyoxyethylene alkyl ethers have a similar oral toxicity to other surfactants and can be regarded as being moderately toxic.

Observe normal precautions appropriate to the circumstances and quantity of material handled. Eye protection and gloves are recommended.

Nonionic emulsifying wax.