Methyl cellulose

Absorption

Cellulose derivatives considered in this report are virtually unabsorbed and little or no degradation of absorbed and little or no degradation of absorbable products occurs in the human digestive tract. In humans, virtually 100 percent of orally ingested methyl cellulose can be recovered in the feces withihn four days, indicating that absorption does not occur.

Toxicity

Organism: Mouse Test type: LD50 Route : Intraperitoneal Reported Dose: 275gm/kg ( 275000mg/kg) Toxic Effect: Details of toxic effects not reported other than lethal dose value
Organism: Mouse Test type: LDLo Route : Intravenous Reported Dose: 1gm/kg ( 1000mg/kg) Toxic Effect: Details of toxic effects not reported other than lethal dose value

Chemical properties

white powder or (often) 2% solution in water, properties

Chemical properties

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 properties

Methyl cellulose is a water soluble, gel-like substance with no odor and no taste.

The Uses of Methyl cellulose

Methyl cellulose is used as a thickener and an emulsifier in various food and cosmetic products; as a gel in advanced cookery and as a lubricant. It is also involved in the treatment of constipation. It acts as a buffer additive in capillary electrophoresis to control electoosmotic flow for improved separations. In paper and textile industries, it is used as a sizing, thereby protecting the fibers from water or oil.

The Uses of Methyl cellulose

Thickener for aqueous and non-aqueous systems, clear films with grease resistance, binders, lubricants, steric stabilizer and water retention aid.

The Uses of Methyl cellulose

As a substitute for water-soluble gums; to render paper greaseproof, in adhesives, as thickening agent in cosmetics, as protective colloid in emulsions, as binder and stabilizer in foods. As fat replacer in the formulation of dietetic foods. Pharmaceutic aid (suspending agent).

The Uses of Methyl cellulose

Methylcellulose is a gum composed of cellulose in which the meth- oxyl groups replace the hydroxyl groups. it is soluble in cold water but insoluble in hot water. solutions increase in viscosity upon heating, gel at 50–55°c, and liquefy upon cooling. it is used in baked goods for moisture retention, and in fruit pie fillings for the reduction of water absorption into the pie crust during baking. it is also used in breaded shrimp where it functions to form an oil barrier film.

Indications

Solutions containing methyl cellulose are used as substitute for tears or saliva if the natural production of these fluids is disturbed. It is also used or constipation, diverticulosis, hemorrhoids and irritable bowel syndrome. Used in the manufacture of capsules in nutritional supplements. Its edible and nontoxic properties provide a vegetarian alternative to the use of gelatin.

Background

Methyl cellulose polymer consisting of numerous linked glucose molecules used as a stabiliser, thickener and emulsifier for foodstuffs and cosmetics. The Degree of Substitution (DS) of a given form of methyl cellulose is defined as the average number of substituted hydroxyl groups per glucose with a theoretical maximum of 3, however more typical values are 1.3 2.6. Methyl cellulose is a hydrophilic white powder in pure form and dissolves in cold (but not in hot) water, forming a clear viscous solution or gel. It is available under a variety of trade names as a treatment for constipation. Like cellulose, it is not digestible, not toxic, and not allergenic

Production Methods

Methylcellulose is prepared from wood pulp (cellulose) by treatment with alkali followed by methylation of the alkali cellulose with methyl chloride. The product is then purified and ground to powder form.

Preparation

Prepared from wood pulp or cotton by treatment with alkali and methylation of alkali cellulose with methyl chloride.

brand name

Cologel (Lilly); Methocel A (Dow Chemical).

General Description

Odorless white or creamy white fibrous powder. Tasteless.

Air & Water Reactions

Methyl cellulose is hygroscopic. Swells in water to a viscous, colloidal solid. Slightly water soluble.

Reactivity Profile

Methyl cellulose is incompatible with strong oxidizing agents. Methyl cellulose is also incompatible with aminacrine HCl, chlorocresol, mercuric chloride, phenol resorcinol, tannic acid and silver nitrate.

Fire Hazard

Flash point data for Methyl cellulose are not available; however, Methyl cellulose is probably combustible.

Pharmaceutical Applications

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.

Biochem/physiol Actions

Methyl cellulose is known to have a molecular size that might pass through placenta. It is useful in visualizing small bowel loops through its overlaps.

Pharmacokinetics

It increases the bulk in your stool, an effect that helps to cause movement of the intestines. It also works by increasing the amount of water in the stool, making the stool softer and easier to pass.

Safety Profile

A poison by intraperitoneal route. When heated to decomposition it emits acrid smoke and irritating fumes.

Safety

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.
Esophageal obstruction may occur if methylcellulose is swallowed with an insufficient quantity of liquid. Consumption of large quantities of methylcellulose may additionally interfere with the normal absorption of some minerals. However, this and the other adverse effects discussed above relate mainly to the use of methylcellulose as a bulk laxative and are not significant factors when methylcellulose is used as an excipient in oral preparations. Methylcellulose is not commonly used in parenteral products, although it has been used in intra-articular and intramuscular injections. Studies in rats have suggested that parenterally administered methylcellulose may cause glomerulonephritis and hypertension.Methylcellulose is considered to be toxic by the intraperitoneal route of administration.
The WHO has not specified an acceptable daily intake of methylcellulose since the level of use in foods was not considered to be a hazard to health.
LD₅₀ (mouse, IP): 275 g/kg

Metabolism

Reported that when methylcellulose was given iv to dog and rabbit , aside from effect upon circulating blood, inability of body to degrade substance led to its retention & accumulation in liver, spleen, lymph nodes, kidney, and vascular walls.

storage

Methylcellulose powder is stable, although slightly hygroscopic. The bulk material should be stored in an airtight container in a cool, dry place.
Solutions of methylcellulose are stable to alkalis and dilute acids at pH 3–11, at room temperature. At pH less than 3, acid-catalyzed hydrolysis of the glucose–glucose linkages occurs and the viscosity of methylcellulose solutions is reduced.On heating, solution viscosity is reduced until gel formation occurs at approximately 50°C;
Methylcellulose solutions are liable to microbial spoilage and antimicrobial preservatives should therefore be used. Solutions may also be sterilized by autoclaving, although this process can decrease the viscosity of a solution.The change in viscosity after autoclaving is related to solution pH. Solutions at pH less than 4 had viscosities reduced by more than 20% subsequent to autoclaving.

Incompatibilities

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.
High concentrations of electrolytes increase the viscosity of methylcellulose mucilages owing to the ‘salting out’ of methylcellulose. With very high concentrations of electrolytes, the methylcellulose may be completely precipitated in the form of a discrete or continuous gel. Methylcellulose is incompatible with strong oxidizing agents.

Regulatory Status

GRAS listed. Accepted as a food additive in the USA, Europe and Japan. Included in the FDA Inactive Ingredients Database (sublingual tablets; IM injections; intrasynovial injections; nasal preparations; ophthalmic preparations; oral capsules, oral suspensions, and oral tablets; topical and vaginal preparations). Included in nonparenteral medicines licensed in the UK. Included in the Canadian List of Acceptable Non-medicinal Ingredients.Reported in the EPA TSCA inventory.