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What are the physical and chemical properties of hydroxypropyl methylcellulose?

By admin / Date Aug 08,2022
Hydroxypropyl methylcellulose (Hypromellose), also known as hypromellose, is a kind of non-ionic cellulose mixed ether. It is a semisynthetic, inactive, viscoelastic polymer commonly used as a lubricant in ophthalmology, or as an excipient or vehicle in oral medicines.

Physical and chemical properties:
Appearance: white or off-white fibrous or granular powder
Stability: The solid is flammable and incompatible with strong oxidants.
Particle size; 100 mesh pass rate is greater than 98.5%; 80 mesh pass rate is 100%. The particle size of special specifications is 40-60 mesh.
Carbonization temperature: 280-300℃
Apparent density: 0.25-0.70g/cm3 (usually around 0.5g/cm3), specific gravity 1.26-1.31.
Discoloration temperature: 190-200℃
Surface tension: 2% aqueous solution is 42-56dyne/cm
Solubility: soluble in water and some solvents, such as appropriate proportion of ethanol/water, propanol/water, etc. Aqueous solutions are surface active. High transparency and stable performance. Different specifications of products have different gel temperatures, and solubility changes with viscosity. The lower the viscosity, the greater the solubility. Different specifications of HPMC have certain differences in performance. The dissolution of HPMC in water is not affected by pH value.
With the decrease of methoxy group content, the increase of gel point, the decrease of water solubility, and the decrease of surface activity of HPMC.
HPMC also has thickening ability, salt resistance, low ash powder, pH stability, water retention, dimensional stability, excellent film-forming properties, and a wide range of enzyme resistance, dispersibility and cohesiveness.

HPMC Hollow Capsules