hypromellose

Hypromellose, or hydroxypropyl methylcellulose (HPMC), is a cellulose ether used as a versatile polymer in pharmaceutical, food, and cosmetic formulations. It is a non-ionic, water-soluble polymer produced by etherifying cellulose with methyl and hydroxypropyl substituents. The degree of substitution and molecular weight vary across grades, yielding a range of viscosities and film-forming properties. HPMC is typically supplied as a powder or granules.

Manufacture and properties: HPMC is prepared from cellulose derived from plant sources such as wood pulp or cotton linter. Through chemical etherification with methylating and hydroxypropylating reagents, cellulose is converted into a polymer with methoxy and hydroxypropyl groups. The resulting material is purified and dried. HPMC is chemically stable, resistant to heat and light, and remains stable across a broad pH range. Depending on grade, it forms viscous solutions and cohesive films, and its viscosity and gelling behavior are selected for specific formulations.

Applications: In pharmaceuticals, HPMC serves as a binder in tablets, a thickener in suspensions, and a film-forming coating for controlled-release and unit-dose preparations. It is also used to produce gelatin-free capsule shells (hypromellose capsules). In foods and beverages, HPMC acts as a thickener, stabilizer, and emulsifier and is approved as a food additive in many regions (often labeled E464). In cosmetics and personal care, it functions as a thickener and film-former in creams, lotions, and makeup, and as a binder in some products.

Safety and regulation: HPMC is regarded as non-toxic and has a long history of safe use in foods and pharmaceuticals. Regulatory approvals vary by region, but it is widely accepted as a food additive and pharmaceutical excipient. High intake may cause laxative effects in sensitive individuals.