PhEur 2002 defines hydroxypropyl methylcellulose as partially O-methylated and partially O- (2-hydroxypropyl) cellulose. Market products have different viscosity and different degrees of substitution of various levels of products. Grade with numerical representation is its 2% aqueous solution at 20℃ apparent density in mPas. USP 25 Models in which the generic name is followed by a four-digit number indicating the substituent content of hydroxypropyl methylcellulose. For example, hydroxypropyl methylcellulose 1 828. The first two digits represent the approximate percentage of methoxy, and the last two represent the approximate percentage of hydroxypropyl. The molecular weight is about 10000 ~ 1500000. Hydroxypropyl methylene cellulose after drying moisture absorption, but the property is stable. The solution is durable at pH 3 ~ 11. The viscosity of the solution decreases as temperature increases. Heating-cooling can make the reversible transformation of hydroxypropyl methylene cellulose from solution to a gel state. Depending on different grades and concentrations, the gelation temperature is 50 ~ 90℃.
The aqueous solution of hydroxypropyl methylcellulose has an anti-enzyme effect and maintains good viscosity stability during long-term storage. However, its aqueous solution is susceptible to microbial attack, so preservative and bacteriostatic agents should be added during storage. When hydroxypropyl methylcellulose is used as a thickening agent in eye drops, benzalkonium chloride is usually added as a preservative. The aqueous solution can be autoclaved. The clumps shake and redisperse as they cool. Hydroxypropyl methylcellulose powder must be stored in an airtight container and a cool and dry place. If you are looking for high quality, high purity and cost-effective Hydroxypropyl methylcellulose, or if you require the latest price of Hydroxypropyl methylcellulose, please feel free to email contact mis-asia.
