Methylcellulose

Synonyms:Benecel; Cellacol; Culminal MC; E461; Mapolose; Methocel; methylcellulosum; Metolose; Tylose; Viscol

Description: Methylcellulose occurs as a white, fibrous powder or granules. It is practically odorless and tasteless. It should be labeled to indicate its viscosity type (viscosity of a 1 in 50 solution).

Chemical Name: Cellulose methyl ether

Coating agent; emulsifying agent; suspending agent; tablet and capsule disintegrant; tablet binder; viscosity-increasing agent.

• Methylcellulose is widely used in oral and topical pharmaceutical formulations.

• In tablet formulations, low- or medium-viscosity grades of methylcellulose are used as binding agents, the methylcellulose being added either as a dry powder or in solution.

• Highviscosity grades of methylcellulose may also be incorporated in tablet formulations as a disintegrant.

• Methylcellulose may be added to a tablet formulation to produce sustained-release preparations.

• Tablet cores may also be spray-coated with either aqueous or organic solutions of highly substituted low-viscosity grades of methylcellulose to mask an unpleasant taste or to modify the release of a drug by controlling the physical nature of the granules.

• Methylcellulose coats are also used for sealing tablet cores prior to sugar coating. Low-viscosity grades of methylcellulose are used to emulsify olive, peanut, and mineral oils.

• They are also used as suspending or thickening agents for orally administered liquids, methylcellulose commonly being used in place of sugar-based syrups or other suspension bases.

• Methylcellulose delays the settling of suspensions and increases the contact time of drugs, such as antacids, in the stomach.

• High-viscosity grades of methylcellulose are used to thicken topically applied products such as creams and gels.

• In ophthalmic preparations, a 0.5–1.0% w/v solution of a highly substituted, high-viscosity grade of methylcellulose has been used as a vehicle for eye drops.

• However, hypromellose-based formulations are now preferred for ophthalmic preparations.

• Methylcellulose is also used in injectable formulations.

• Therapeutically, methylcellulose is used as a bulk laxative; it has also been used to aid appetite control in the management of obesity, but there is little evidence supporting its efficacy.

Methylcellulose is incompatible with aminacrine hydrochloride; chlorocresol; mercuric chloride; phenol; resorcinol; tannic acid; silver nitrate; cetylpyridinium chloride; p-hydroxybenzoic acid; paminobenzoic acid; methylparaben; propylparaben; and butylparaben. Salts of mineral acids (particularly polybasic acids), phenols, and tannins will coagulate solutions of methylcellulose, although this can be prevented by the addition of ethanol (95%) or glycol diacetate. Complexation of methylcellulose occurs with highly surface-active compounds such as tetracaine and dibutoline sulfate

Methylcellulose is widely used in a variety of oral and topical pharmaceutical formulations. It is also extensively used in cosmetics and food products, and is generally regarded as a nontoxic, nonallergenic, and nonirritant material. Following oral consumption, methylcellulose is not digested or absorbed and is therefore a noncaloric material. Ingestion of excessive amounts of methylcellulose may temporarily increase flatulence and gastrointestinal distension. In the normal individual, oral consumption of large amounts of methylcellulose has a laxative action and medium- or high-viscosity grades are therefore used as bulk laxatives.

Observe normal precautions appropriate to the circumstances and quantity of material handled. Dust may be irritant to the eyes and eye protection should be worn. Use in a well-ventilated area. Excessive dust generation should be avoided to minimize the risk of explosion. Methylcellulose is combustible. Spills of the dry powder or solution should be cleaned up immediately, as the slippery film that forms can be dangerous.

Ethylcellulose; hydroxyethyl cellulose; hydroxyethylmethyl cellulose; hypromellose.