Product Details
Category
Thickening Agents; Suspending Agents; Gel Agents
Molecular Formula
C8H15O8-(C10H18O6 ) n- C8H15O8
Grade
Pharmceutical Excipients
Chemical Name
Cellulose, 2-hydroxypropyl methyl ether
Synonyms
Cellulosehydroxypropyl methyl ether; HPMC; methyl hydroxypropylcellulose; hydroxypropyl ; methylcellulose propylene glycol ether
Administration route
Eye drops and oral
Dosage Form
Ophthalmic preparations, oral capsules, suspensions, syrups and tablets; Topical and vaginal preparations
Stability and Storage Conditions
Hydroxypropyl methylene cellulose after drying moisture absorption, but the property is stable. The solution is stable at pH 3 ~ 11. The viscosity of solution decreases as temperature increases. Heating - cooling can make the reversible transformation of hydroxypropyl methylene cellulose from solution to gel state. Depending on different grades and concentrations, the gelation temperature is 50 ~ 90℃. The aqueous solution of hydroxypropyl methylcellulose has 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. Aqueous solution can be autoclaved. The clumps shake and redisperse as they cool. Hydroxypropyl methylcellulose powder must be stored in an airtight container and kept in a cool and dry place.
Source and Preparation
The refined cotton cellulose is treated with lye at 35-40℃ for half an hour, pressed, the cellulose is crushed, and properly aged at 35℃, so that the average degree of polymerization of the obtained alkali fiber is within the required range. The alkali fibers were put into etherification kettle, followed by propylene oxide and methyl chloride, and etherized at 50-80℃ for 5h, with the highest pressure of about 1.8MPa. The reaction products were post-treated (neutralized by hydrochloric acid, iron removed by oxalic acid, washed and dried). Raw material consumption quota cotton pulp 1100kg/t, methyl chloride and propylene oxide 4300kg/t, solid alkali 1200kg/t, hydrochloric acid 30kg/t, oxalic acid 50kg/t.
Applications
Thickening and suspending agents and gels for topical preparations, especially ophthalmic preparations.
Safety
Hydroxypropyl methylcellulose is widely used as excipients in oral and topical preparations. It is also widely used in cosmetics and food. It is generally believed that hydroxypropyl methylcellulose is non-toxic and non-irritating material, but excessive oral administration can cause diarrhea. Ordinary intake is not harmful to human health, WHO has no clear rules on the daily intake of hydroxypropyl methylcellulose. LD50(mice, intraperitoneal injection): 5 g/kg LD50(rats, intraperitoneal injection): 5.2 g/kg
Incompatibilities
Hydroxypropyl methylcellulose and some oxidants have incompatibility. Since hydroxypropyl methylcellulose is a nonionic compound, it can form insoluble precipitates with metal salts or ionized organic matter.