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| | POLYOXYETHYLENE ALKYL ETHERS Basic information |
| | POLYOXYETHYLENE ALKYL ETHERS Chemical Properties |
| | POLYOXYETHYLENE ALKYL ETHERS Usage And Synthesis |
| Chemical Properties | 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. | | Production Methods | Polyoxyethylene alkyl ethers are prepared by the condensation of
linear fatty alcohols with ethylene oxide. The reaction is controlled
so that the required ether is formed with the polyethylene glycol of
the desired molecular weight. | | Pharmaceutical Applications | 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. | | Safety | 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.
(mouse, oral): 2.60 g/kg
(rabbit, skin): 40 g/kg/4 week intermittent
(rat, oral): 2.50 g/kg
Polyoxyethylene lauryl ether:
(mouse, IP): 0.16 g/kg
(mouse, IV): 0.10 g/kg
(mouse, oral): 4.94 g/kg
(mouse, SC): 0.79 g/kg
(rat, IV): 0.027 g/kg
(rat, oral): 8.60 g/kg
(rat, SC): 0.95 g/kg
Polyoxyethylene oleyl ether:
(rat, oral): 25.8 g/kg | | storage | Polyoxyethylene alkyl ethers are chemically stable in strongly acidic
or alkaline conditions. The presence of strong electrolytes may,
however, adversely affect the physical stability of emulsions
containing polyoxyethylene alkyl ethers.
On storage, polyoxyethylene alkyl ethers can undergo autoxidation,
resulting in the formation of peroxides with an increase in
acidity. Many commercially available grades are thus supplied with
added antioxidants. Typically, a mixture of 0.01% butylated
hydroxyanisole and 0.005% citric acid is used for this purpose.
Polyoxyethylene alkyl ethers should be stored in an airtight
container, in a cool, dry place. | | Incompatibilities | 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. | | Regulatory Status | Included in nonparenteral medicines licensed in the USA and UK.
Included in the Canadian List of Acceptable Non-medicinal
Ingredients. |
| | POLYOXYETHYLENE ALKYL ETHERS Preparation Products And Raw materials |
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