Cellulose hydroxypropyl methyl ether

Cellulose, 2-hydroxypropyl ether. See Hydroxypropylcellulose Cellulose hydroxypropyl methyl ether Cellulose 2-hydroxypropyl methyl ether. See Hydroxypropyl methylcellulose Cellulose methyl Cellulose methylate Cellulose methyl ether. See Methylcellulose... 

Synonyms Carbohydrate gum Cellulose hydroxypropyl methyl ether Cellulose 2-hydroxypropyl methyl ether HPMC Hypromellose Methyl hydroxypropyl cellulose MHPC Definition Propylene glycol ether of methyl cellulose Properties Wh. gran, powd. sol. in most polar soivs., cold water swells in water to produce a clear to opalescent vise, colloidal sol n. insol. in hot water and in anhyd. alcohol, ether, chloroform nonionic Toxicoiogy LD50 (IP, rat) 5200 mg/kg mildly toxic by IP route TSCA listed... 

Cellulose hydroxypropyl methyl ether Cellulose 2-hydroxypropyl methyl ether. See Hydroxypropyl methylcellulose Cellulose, 2-[2-hydroxy-3-(trimethylammonio)propoxy]ethyl ether, chloride. See Polyquaternium-24 Cel I u I ose, 2-(2-hyd roxy-3-(tri methyl am m on i u m) propoxy) ethyl ether, chloride. See Poiyquaternium-10... 

Synonyms Carbohydrate gum Cellulose hydroxypropyl methyl ether Cellulose 2-hydroxypropyl methyl ether HPMC Hypromellose... 

Hydroxypropyl Methyl Cellulose (Cellulose Hydroxypropyl Methyl Ether)... 

Aqoat Aqoat AS-HF/HG Aqoat AS-LP/LG-, Aqoat AS-MF/ MG cellulose, 2-hydroxypropyl methyl ether, acetate succinate HPMCAS. 

Cellulose phthalate hydroxypropyl methyl ether HPMCP hydroxypropyl methylcellulose benzene-1,2-dicar boxy late 2-hydroxypropyl methylcellulose phthalate methylhydroxypro-pylcellulose phthalate. 

Semisynthetic gels are also very useful for the creation of drug delivery systems. Cellulose ethers are particularly important in drug delivery. These compounds are made by derivatizing the cellulose hydroxyls with various groups such as hydroxypropyl, methyl, or carboxymethyl. This substitution breaks up the crystallinity of native cellulose and makes it water-soluble [23], The degree... 

Surface pressure(mN/m) dependence on time hrs.) of aqueous cellulose ether (both M = 5 10 ) solutions. O 1000 ppm hydroxyethyY cellulose (HEC) 0,25Oppm hydroxypropyl methyl cell-ulose(HPMC) A, 250ppm HPMC, lOOOppm HEC. 

Research on nasal powder drug delivery has employed polymers such as starch, dextrans, polyacrylic acid derivatives (e.g., carbopol, polycarbophil), cellulose derivatives (microcrystalline cellulose, semicrystalline cellulose, hydroxypropylmethyl cellulose, hydroxypropyl cellulose, carboxymethyl cellulose), chitosan, sodium alginate, hyaluronans, and polyanhydrides such as poly(methyl vinyl ether-co-maleic anhydride) (PVM/MA). Many of these polymers have already been used as excipients in pharmaceutical formulations and are often referred to as first-generation bioadhesives [38-45], In nasal dry powder a single bioadhesive polymer or a... 

Cellulose esters or ethers such as methylcellulose (MC), ethylcellulose (EC), hydroxyethyl cellulose (HEC), hydroxypropyl cellulose (HPC), hydroxypropyl methylcellulose/hypromellose (HPMC), hypromeUose phthalate (HPMCP), hypromellose acetate phthalate (HPMCAP), hypromellose acetate succinate (HPMCAS), cellulose acetate (CA) and derivates Poly (methyl) methacrylates (Eudragit L, S, E, RS/ RL)... 

Hydrophilic sustained release matrix tablets are often prepared from cellulose ethers, e.g., hydroxypropyl methyl cellulose. When these materials are exposed to water, the surface of the polymer becomes hydrated. In this way, a gel layer is formed on the glassy core. This changes the barrier properties that are controlling the drug release by a diffusion mechanism. 

Poly (2-hydroxypropyl. Me) ether Hydro-xypropyl methyl cellulose. HPMC. E463. Hypromellose, USAN. Hydroxypropyl-methylcellulose, JAN. Cellulose hydro-xypropyl methyl ether, BAN, INN [9(X)4-65-3] Prepared by etherification of alkaline cellulose with methyl chloride and propylene oxide. Commercial samples have methyl DS values of 1.1-2.0 and hydroxypropyl MS values of 0.1 - 1.0. Thickening and binding agent with widespread industrial uses in adhesives, building products, films, protective creams and colloids. Approved for food use in US and EU. Used in deep fried batters. Shows better water solubility and electrolyte tolerance than methylcellulose. Component of artificial tears. 

Hydroxypropyl methyl-ceUulose phthalate (HPMCP) Cellulose ethers anionic 137 °C (for HP-50) 133 °C (for HP-55) 80,000- 130,000 Above pH 5.0 Hygroscopic 28 185 °C Hot melt extrusion Spray drying... 

Two approaches are discussed for the preparation of enzymatically controlled drug delivery systems a calcium-responsive biodegradable drug delivery system based on a mixture of starch with HPMC (hydroxypropyl methyl cellulose ether) (biodegradable) and the starch hydrolytic enzyme, alpha-amylase, in its non-active form and a glucose responsive insulin delivery system based on the hydrogel poly(2-hydroxyethyl methacrylate-co-N,N-dimethylaminoethyl methacrylate), with entrapped glucose oxidase, catalase and insulin. In both systems, the sensitivity... 

For a large number of polymers, the conditions for a LCST behavior are given. This includes polymers containing ether groups, such as poly(vinyl methyl ether), polymers with alcohol groups, like hydroxypropyl cellulose, and polymers... 

Hydroxypropyl methyl cellulose (Scheme 5.2) is also known as Benecel MHPC E464 hydroxypropyl methylceUulose HPMC hypromellosum Methocel methylcellulose propylene glycol ether methyl hydroxypropylcellulose Metolose MHPC Pharmacoat Tylopur and Tylose MO. 

Since the hydroxyl groups in cellulose are reactive and can be easily functionalized, cellulose has been made into a large number of derivatives in the form of ethers, esters, and acetals, such as methyl cellulose, hydroxypropylcellulose, hydroxypropyl methyl cellulose, and carboxymethyl cellulose. These cellulose derivatives are soluble in a variety of solvents and can be easily processed into various forms, such as... 

In context with RR, the following w. should be mentioned alginates (- sodium alginate) ->car-boxymethyl cellulose - carrageenan - guar gum - locust gum gum arabic - hydroxyethyl cellulose - hydroxypropyl cellulose - methyl-cellulose - mixed ethers of cellulose ->pectin, - starches, starch esters, - starch ethers, - oxidized starches, -+dextrins, - starch hydrolysis products, - maltodextrins and their derivatives, - dextran, - scleroglucan, - maltodextrins and - xanthan. 

Etherification. Carbohydrates are involved in ether formation, both intramoleculady and intermoleculady (1,13). The cycHc ether, 1,4-sorbitan, an 1,4-anhydroalditol, has already been mentioned. 3,6-Anhydro-a-D-galactopyranosyl units are principal monomer units of the carrageenans. Methyl, ethyl, carboxymethyl, hydroxyethyl, and hydroxypropyl ethers of cellulose (qv) are all commercial materials. The principal starch ethers are the hydroxyethyl and hydroxypropylethers (see Cellulose ethers Starch). 

Antiredeposition agents contribute to the appearance of washed fabrics. Sodium carboxymethylceUulose [9004-32-4], NaCMC is the most widely used, and on cotton fabrics, the most effective. With the advent of synthetic fabrics, other cellulose derivatives, eg, methylceUulose [9004-67-5], hydroxybutjiceUulose, hydroxypropyl- and mixed methyl and hydroxybutyceUulose ethers have been shown to be more effective than NaCMC (8) (see... 

A possible way to lower the costs of fibers and films of regenerated cellulose would be to run cellulose through a twin-screw ultrasonic extruder with a minimum of solvent and pass the extrudate through a stream of hot air to recover the solvent for reuse. This stronger cellophane could be used in place of many plastic films used today. A great number of derivates of cellulose have been made. Methyl, ethyl, carboxymethyl, hydroxyethyl, and hydroxypropyl ethers are made commercially today. These are used as water-soluble polymers, except for ethylcellulose, which is a tough plastic used in screwdriver handles and such. 

Methylcellulose solutions generally form gels at higher temperatures. The gelation temperature is increased when hydroxyethyl or hydroxypropyl groups are introduced into the methylcellulose (cf. Section 9.6.2). Hy-droxyethylmethylcellulose and hydroxypropylmethylcellulose are prepared industrially by the reaction of alkali cellulose first with ethylene oxide or propylene oxide and then with methyl chloride. Similarly, hydroxyethyl-ethylcellulose is prepared by consecutive ethylene oxide and ethyl chloride treatments. Cellulose ethers with both methyl and ethyl groups have also been manufactured. 

A purified form of cellulose, obtained from cotton linters or wood pulp, is reacted with sodium hydroxide solution to produce a swollen alkali cellulose that is chemically more reactive than untreated cellulose. The alkali cellulose is then treated with chloromethane and propylene oxide to produce methyl hydroxypropyl ethers of cellulose. The fibrous reaction product is then purified and ground to a fine, uniform powder or granules. 

Cellulose ethers, more particularly methyl cellulose (MQ, methylhydroxypro-pyl cellulose (MHPC) and hydroxypropyl cellulose (HPC) are used as protective colloids also called primary suspending agents in suspension polymerization for the manufacturing of S-PVC. Their role is maintaining the particle size of the resin. Hydroxyethyl cellulose (HEC) is preferred for manufacturing of vinyl acetate emulsion polymers and as a thickening agent in dispersimi paints. 

Most polysaccharides used in foods are predominantly hydrophilic and not surface active. Some polysaccharides, however, notably gum arabic, contain minor protein moieties, and do adsorb onto O-W (and presumably A-W) interfaces. By chemical modification, hydrophobic groups can be introduced. The best known examples are cellulose ethers, such as methyl cellulose and hydroxypropyl cellulose, which substances are well soluble in water (at least below 40° C) and strongly surface active. 

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