[9004-65-3]

This product is hydroxypropyl methyl cellulose, a semi-synthetic compound that can be prepared by two methods: (1) Treating cotton linter or wood pulp fiber with sodium hydroxide, followed by reaction with chloromethane and propylene oxide, then refining and pulverizing to obtain; (2) Treating a suitable grade of methyl cellulose with sodium hydroxide, reacting with propylene oxide under high temperature and pressure to the desired extent, and refining. The molecular weight ranges from 10,000 to 1,500,000.

【Characteristics】 This product is a white or off-white fibrous or granular powder.

Loss on drying: When dried at 105°C for 2 hours, the loss in weight should not exceed 5.0% (General Rule 0831).

Residue on ignition: Using 1.0g of the sample, test according to the method (General Rule 0841); the residue should not exceed 1.5%.

Heavy metals: Using the residue from the ignition test, examine according to the method (General Rule 0821, Method 2); the content of heavy metals should not exceed 10 parts per million.

Arsenic salt: Mix 1.0g of the sample with 1.0g of calcium hydroxide, add water and stir evenly. After drying, first char with a low flame, then ignite completely at 600°C until ashed. Allow to cool, add 5ml of hydrochloric acid and 23ml of water, and test according to the method (General Rule 0822); it should comply with the regulation (0.0002%).

【Assay】 Methoxy: Determine according to the method for methoxy, ethoxy, and hydroxypropoxy groups (General Rule 0712). If using the first method (gas chromatography), heat at 130°C ± 2°C for 30 minutes, shake vigorously for 5 minutes, continue heating at 130°C ± 2°C for 30 minutes, or stir magnetically or oscillate at 130–150°C for 60 minutes; the rest is the same. If using the second method (volumetric method), weigh accurately and determine according to the method. Subtract the product of the hydroxypropoxy content (%) and (31/75 × 0.93) from the measured methoxy content (%).

Hydroxypropoxy: Determine according to the method for methoxy, ethoxy, and hydroxypropoxy groups (General Rule 0712). If using the first method (gas chromatography), heat at 130°C ± 2°C for 30 minutes, shake vigorously for 5 minutes, continue heating at 130°C ± 2°C for 30 minutes, or stir magnetically or oscillate at 130–150°C for 60 minutes; the rest is the same. If using the second method (volumetric method), weigh 0.1g accurately and determine according to the method.

【Category】 Pharmaceutical excipient, release retardant, coating material, etc.

【Storage】 Keep tightly closed.

【Labeling】 The substitution type should be indicated; when used as a matrix-forming agent for sustained-release tablets, the particle size specification should be indicated, and the viscosity specification should be indicated in mPa·s.