The dissolution methods of HPMC include: cold water instant solution method and hot solution method, powder mixing method and organic solvent wetting method
The cold water solution of HPMC is treated with glyoxal, which is rapidly dispersed in cold water. At this time, it is not a real solution. It is a solution when the viscosity increases. The hot solution is not treated with glyoxal. When the volume of glyoxal is large, it will disperse rapidly, but the viscosity will rise slowly.
Since HPMC is insoluble in hot water, HPMC can be evenly dispersed in hot water at the initial stage, and then quickly dissolved when cooled.
Two typical methods are described below:
1) Put the required amount of hot water into the container and heat it to about 70 ℃. Hydroxypropyl methylcellulose was gradually added under slow stirring, HPMC began to float on the water, and then gradually formed slurry, which was cooled under stirring.
2) Add 1 / 3 or 2 / 3 of the required water into the container, heat to 70 ℃, disperse HPMC according to the method of 1) to prepare hot water slurry; Then add the remaining cold water to the hot water slurry, stir and cool the mixture.
Cold water instant HPMC can be dissolved by adding water directly, but the initial viscosity time is 1 to 15 minutes. The operating time shall not exceed the starting time.
Powder mixing method: HPMC powder is completely dispersed by dry mixing with the same or more powder components, and then dissolved with water. In this case, HPMC can be dissolved without caking.
Organic solvent wetting method:
Hydroxypropyl methylcellulose can be dissolved by dispersing it into organic solvent or wetting it with organic solvent, and then adding it to cold water or cold water. Ethanol, ethylene glycol, etc. can be used as organic solvent.
Post time: Jan-20-2022