Hydroxypropyl methylcellulose

Hydroxypropyl methylcellulose (HPMC), also known as hypromellose, is a semisynthetic, inert, viscoelastic polymer used in a variety of industries. It is a derivative of cellulose, the most abundant organic polymer on Earth.

History

The production of hydroxypropyl methylcellulose was first patented in the United States in 1953. Since then, it has been widely used in various industries due to its unique properties.

Production

Hydroxypropyl methylcellulose is produced by treating cotton linter or wood pulp with an alkali solution to remove impurities. The resulting cellulose is then reacted with methyl chloride and propylene oxide to introduce the hydroxypropyl and methyl groups.

Properties

Hydroxypropyl methylcellulose is a white to slightly off-white powder. It is soluble in water, but not in organic solvents. It forms a colloid when dissolved in water, giving it its viscoelastic properties. It is also thermoplastic, meaning it softens when heated and hardens when cooled.

Uses

Hydroxypropyl methylcellulose has a wide range of uses due to its unique properties. It is used as a thickening agent, emulsifier, and stabilizer in the food industry. In the pharmaceutical industry, it is used as a controlled-release agent in oral medications and as an excipient in tablet formulations. It is also used in the construction industry as a thickener and stabilizer in cement and plaster mixtures.

Health and safety

Hydroxypropyl methylcellulose is generally considered safe for consumption and use. However, it can cause mild irritation if it comes into contact with the eyes or skin. Ingestion of large amounts can cause gastrointestinal discomfort.

See also

• Cellulose
• Methylcellulose
• Carboxymethyl cellulose
• Polymer

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