Cellulose hydroxy propyl

Carboxymethyl cellulose cellulose acetate cellulose acetate phthalate cellulose, microcrystalline ethylcellulose hypromellose hypromellose phthalate hydroxyethyl cellulose hydroxy-propyl cellulose methylcellulose. 

Gums, vegetable Hydrocarbon resins Hydroxy propyl cellulose Hydroxy propyl methyl cellulose Hydroxy propyl methyl cellulose acetate succinate (enteric)... 

Attama, A.A. Akpa, P.A. Onugwu, L.E. Igwilo, G. Novel buccoadhesive dehvery system of hydrochlorothiazide formulated with ethyl cellulose-hydroxy propyl methyl celluolose interpolymer complex. Sci. Res. Essays 2008, 3 (6), 343-347. 

Product Agar Algin Carra-g eenan Furcel-1 aran Arabic Xan -tha n Traga- canth Hydroxy- propyl cellulose Locust bean Guar cmD Methyl cellulose Karaya... 

Hydroxy propyl cellulose, like methyl cellulose, is soluble in cold water but not in hot, precipitating above 38°C. It was introduced by Hercules in 1968 (Klucel) for such uses as adhesive thickeners, binders, cosmetics and as protective colloids for suspension polymerisation. The Dow company market the related hydroxypropylmethyl cellulose (Methocel) and also produce in small quantities a hydroxyethylmethyl cellulose. 

Adsorption behavior and the effect on colloid stability of water soluble polymers with a lower critical solution temperature(LCST) have been studied using polystyrene latices plus hydroxy propyl cellulose(HPC). Saturated adsorption(As) of HPC depended significantly on the adsorption temperature and the As obtained at the LCST was 1.5 times as large as the value at room temperature. The high As value obtained at the LCST remained for a long time at room temperature, and the dense adsorption layer formed on the latex particles showed strong protective action against salt and temperature. Furthermore, the dense adsorption layer of HPC on silica particles was very effective in the encapsulation process with polystyrene via emulsion polymerization in which the HPC-coated silica particles were used as seed. 

In this study, adsorption behavior of water soluble polymers and their effect on colloid stability have been studied using polystyrene latices plus cellulose derivatives. As the aqueous solution of hydroxy propyl cellulose(HPC) has a lower critical solution temperature(LCST), near 50 °C(6 ), an increased adsorption and strong protection can be expected by treating the latices with HPC at the LCST. 

The study of mesophases of cellulose and cellulose derivatives is an active field which has expanded rapidly since the initial observation of liquid crystms of hydroxy-propyl cellulose in 1976. There are two areas that warrant turther investigation recent observations regarding the influence of solvent and/or substituents on the cholesteric helicoidal twist await a theoretical explanation there is a lack of careful studies to permit a theoretical treatment of the behavior of ordered celltdose phases. To date, no applications have been developea where the unusual properties of cellulose derivatives are utilized. 

Hydroxy- propyl hydroxypropyl cellulose/polysacch. by etherification of cellulose from plants emulsifier for cosmetics... 

In concluding this section, we should touch upon phase boundary concentration data for poly(p-benzamide) dimethylacetamide + 4% LiCl [89], poly(p-phenylene terephthalamide) (PPTA Kevlar)-sulfuric acid [90], and (hydroxy-propyl)cellulose-dichloroacetic acid solutions [91]. Although not included in Figs. 7 and 8, they show appreciable downward deviations from the prediction by the scaled particle theory for the wormlike hard spherocylinder. Arpin and Strazielle [30] found a negative concentration dependence of the reduced viscosity for PPTA in dilute Solution of sulfuric acid, as often reported on polyelectrolyte systems. Therefore, the deviation of the Ci data for PPTA in sulfuric acid from the scaled particle theory may be attributed to the electrostatic interaction. For the other two systems too, the low C] values may be due to the protonation of the polymer, because the solvents of these systems are very polar. 

The effect of ions on the degree of hydration of cellulose ethers has been studied. Depending on the polymer, the type and concentration of ions can affect to varying degrees the extent of hydration. Changes in the hydration state result primarily in solution-viscosity and cloud-point changes. These effects were demonstrated with hydroxy propyl cellulose.16... 

Hydroxy propyl methyl cellulose (HPMC).35 HPMC is a partly O-methylated and 0-(2-hydroxypropylated) cellulose available in several grades that vary in viscosity and extent of substitution. It is used widely in pharmaceutical formulations, especially in oral products, as a tablet binder, in film coating, and as controlled release matrix. Soluble in cold water, it forms a viscous colloidal solution. For a 2% aqueous solution (20°C), viscosity can range from 2.4 to 120,000 mPa-s. High-viscosity grades can be used to retard the release of water-soluble drugs from a matrix. 

Jansen PJ, Kemp CA, Maple SR, Baertschi SW. Characterization of Impurities found by interaction of Duloxetine HC1 with enteric polymers hydroxy-propyl methyl cellulose acetate succinate and hydroxypropyl methylcellulose phthalaie. J Pharm Sci 1998 87(1) 81—85. 

Hydroxypropylcellulose is applied for similar purposes as hydroxyethyl-cellulose although its use is more limited. Because hydroxypropyl substitution improves thermoplasticity and solubility in organic solvents, hydroxypropylcellulose can also be used as a thickener for organic solutions. Hydroxy-propylation of cellulose does not result in water and alkali soluble products until the MS is close to 4. 

Solid formulations for sustained drug release may contain mesogenic polymers as excipients. The mesogenic polymers form a matrix, which is usually compressed into tablets. Some of the most frequently used excipients for sustained release matrices include cellulose derivatives, which behave like lyotropic liquid crystals when they are gradually dissolved in aqueous media. Cellulose derivatives such as hydroxy-propyl cellulose or hydroxy-propylmethyl cellulose form gel-like lyotropic mesophases in contact with water, through which diffusion takes place relatively slowly. Increasing dilution of the mesophase with water transforms the mesophase to a highly viscous slime and then to a colloidal polymer solution. 

Suspending agent systems such as a pseudoplastic (sodium carboxymethylcellulose) in combination with a clay (hydrated colloidal magnesium aluminum silicate) or blends and coprecipitates of sodium carboxymethylcellulose and microcrystalline cellulose exhibit some thixotropic flow characteristics. Other pseudoplastics such as hydroxyethylcellulose or hydroxy-propyl methyl cellulose may be required to overcome possible in compatibilities with sodium carboxymethylcellulose. 

Cellulosics sodium carboxymethylcellulose, microcrystalline cellulose (including coprecipitates and blends of the two), hydroxyethylcellulose, hydroxy-propyl cellulose, hydroxypropyl methylcellulose, methylcellulose, starch, sodium starch glycolate, and powdered cellulose... 

Banker G, Peck G, Jan S, Pirakitikulr P. Evaluation of hydroxy-propyl cellulose and hydroxypropyl methyl cellulose as aqueous based film coatings. Drug Dev Ind Pharm 1981 7 693-716. 

Note that some cellulose ether products possess hydroxy-propyl substitutions in addition to methyl substitutions but are designated with the same trade name in a product line, differing only by a unique identifier code. These products should not be confused with the products that contain only methyl substitutions. A specification for methylcellulose is contained in the Food Chemicals Codex (FCC). 

Anonymous. Final report on the safety assessment of hydroxy-ethylcellulose, hydroxypropylcellulose, methylcellulose, hydroxy-propyl methylcellulose and cellulose gum. Am Coll Toxicol 1986 5(3) 1-60. 

Many ATPS systems contain a polymer which is sugar based and a second one which is of hydrocarbon ether type. Sugar-based polymers include dextran (Dx), hydroxy propyl dextran (HPDx), FicoU (Fi) (a polysaccharide), methyl cellulose (MC), or ethylhydroxyethyl cellulose (EHEC). Hydrocarbon ether-type polymers include poly (ethylene glycol) (PEG), poly (propylene glycol) (PPG), or the copolymer of PEG and PPG. De-rivatized polymers can also be useful, such as PEG-fatty acids or di-ethylaminoethyl-dextran (Dx-DEAE). 

Isotropic polymeric systems as well as particulate systems might also show time-dependent moduli after cessation of flow. As long as the shear does not induce structure growth, the moduli always increase with time after flow. An increase of the moduli upon cessation of flow has also been reported for thermotropic PLCs (18) as well as for lyotropic solutions of hydroxy propyl cellulose in water (19) and in acetic add (20). The possibility of changing in either direction seems to be characteristic for mesomorphic materials. A fundamental theory for describing complex moduli does not exist for such materials. The present results, combined with the information about optical relaxation mentioned above, could be explained on the basis of reorientation of domains or defects. The different domains orient differently, even randomly, at rest whereas flow causes an overall orientation. Depending on the molecular interaction the flow could then cause an increase or decrease in moduli as recently suggested by Larson (21). 

Silica fume which is a by-product in the manufacture of ferrosilicon was used as a dispersant for carbon fibers in all the mixes. The chemical and physical properties of the silica fume is listed in Table 1. Polycarboxylie acid-type superplasticizer and hydroxy propyl methyl cellulose (HPMC, viscosity 3500-5600mPa s at 20°C as 2% aqueous solution) were employed as chemical admixtures. 

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