Ethylcellulose

• BPEthylcellulose
• Ph. Eur.Ethylcellulose
• USP–NFEthylcellulose

Aquacoat ECD; Aqualon; cellulose ethyl ether; Ethocel; ethylcellulosum; Surelease; E462

Cellulose ethyl ether · [9004-57-3]

Repeat unit C6H7O2(OH)3−x(OC2H5)x, degree of substitution x ≈ 2.25–2.6

Coating agent, film former, Release-modifying polymer, Binder

Typical concentrations: 1–3% binder · Dosage forms: Solid

A water-insoluble polymer used mainly as a release-controlling film coating for tablets, pellets and granules, applied either from organic solvents or as aqueous dispersions (Aquacoat ECD, Surelease). It is also used for taste masking, microencapsulation, as a matrix former in extended-release tablets, as a binder in granulation and as a thickener in non-aqueous topical systems. Typical concentrations: microencapsulation 10–20%; sustained-release coating 3–20%; tablet coating 1–3%; tablet granulation 1–3%.

An ethyl ether of cellulose, a partially ethoxylated polysaccharide. It is a free-flowing, white to light tan, tasteless and odourless powder. Grades differ in ethoxyl content and in viscosity (molecular weight).

Ethoxyl content

44.0–51.0% (dried basis)

Viscosity grades

nominal about 4 to 100 mPa s or more (5% w/w in toluene–ethanol 80:20)

Glass transition temperature

about 129–133 °C

Solubility

practically insoluble in water, glycerin and propylene glycol; soluble in chloroform, ethanol, ethyl acetate, methanol and toluene (depending on ethoxyl content)

A stable, slightly hygroscopic material that resists alkalis but is more sensitive to acids. It can undergo oxidative degradation when exposed to sunlight or UV light at high temperature, and an antioxidant may be added. Store in a well-closed container in a cool, dry place.

Incompatible with paraffin wax and microcrystalline wax. Avoid strong oxidising agents.

Prepared by treating purified cellulose (wood pulp or cotton linters) with sodium hydroxide to form alkali cellulose, which is then reacted with ethyl chloride. The product is washed, dried and milled.

Not metabolised after oral administration and regarded as non-toxic and non-irritant in oral and topical products. It is not suitable for parenteral use.

Observe normal precautions for the quantity handled. Avoid inhaling the dust and use eye protection. Fine dust can form explosive mixtures with air, and the organic solvents used for coating solutions are usually flammable.

Accepted as a food additive in Europe (E462). Included in the FDA Inactive Ingredient Database (oral capsules, suspensions and tablets; topical and vaginal preparations) and in non-parenteral medicines licensed in Europe.

Hydroxypropyl cellulose; hypromellose; methylcellulose.

Ethylcellulose films are brittle without a plasticiser such as dibutyl sebacate or triethyl citrate. Aqueous dispersions need adequate coalescence and usually a curing step to give stable release, and water-soluble pore formers (for example hypromellose) are often added to adjust the release rate.