Hydroxypropylmethylcellulose (HPMC) is a cellulose ether variety that has rapidly increased in production and dosage in recent years. They are non ionic cellulose mixed ethers made from refined cotton after alkalization treatment, using epoxy propane and chloromethane as etherification agents, through a series of reactions. Their degree of substitution is generally 1.2-2.0. Their properties are influenced by the content of methoxy and hydroxypropyl groups. It is a odorless, odorless, and non-toxic white powder. They have the characteristics of thickening capacity, PH stability, water retention, dimensional stability, film-forming, enzyme resistance, dispersibility and thermal gelation.