Description

Hypromellose (INN), short for hydroxypropyl methylcellulose (HPMC), is a semisynthetic, inert, viscoelastic polymer used as eye drops, as well as an excipient and controlled-delivery component in oral medicaments, found in a variety of commercial products.

Chemistry

Hypromellose is a solid, and is a slightly off-white to beige powder in appearance and may be formed into granules. The compound forms colloids when dissolved in water. This non-toxic ingredient is combustible and can react vigorously with oxidizing agents.
Hypromellose in an aqueous solution, like methylcellulose, exhibits a thermal gelation property. That is, when the solution heats up to a critical temperature, the solution congeals into a non-flowable but semi-flexible mass.

Uses

As a food additive, hypromellose is an emulsifier, thickening and suspending agent, and an alternative to animal gelatin.[3] Its Codex Alimentarius code (E number) is E464.

It is used as a vegan alternative to gelatine in medicines and supplements; as a treatment for dry eye syndrome and as a gluten replacement in gluten-free bread.In gluten-free bread it improves the elasticity, stability, volume and moisture retention.This makes a loaf more akin to gluten containing bread (source: Study on effects of HPMC and CMC on the properties of gluten-free bread).