Hydroxypropyl cellulose solubility

Hydroxypropyl cellulose Soluble Precipitates <40°C None See Appendix 3, Figure A3.20... 

Paine et al. [85] extensively studied the effect of solvent in the dispersion polymerization of styrene in the polar media. In their study, the dispersion polymerization of styrene was carried out by changing the dispersion medium. They used hydroxypropyl cellulose (HPC) as the stabilizer and its concentration was fixed to 1.5% within a series of -alcohols tried as the dispersion media. The particle size increased from only 2.0 /itm in methanol to about 8.3 /itm in pentanol, and then decreased back to 1 ixm in octadecanol. The particle size values plotted against the Hansen solubility parameters... 

Suspension of water soluble solids in oil can be achieved by a variety of chemical additives. Chemical suspension additives that have been suggested include alkyl mercaptophosphonic acids(174), organophylic clay plus hydroxypropyl cellulose(175), polyols(176), aluminum stearate(177), organophylic clay plus surfactant(178-181), aluminum phosphate esters(182), and acrylate copolymers(183-184). 

Regioselective enzymatic acylation of large, insoluble polysaccharides is still a quite difficult task and therefore it is not surprising that only scant data have been reported up to now, most of them describing reaction outcomes which met with limited success. Nevertheless, enzymatic derivatization of polysaccharides has been performed in nonpolar organic solvents using insoluble polysaccharides with soluble [51] or suspended enzymes [52]. Chemically modified celluloses with either enhanced solubility or more readily accessible hydroxyl groups, like cellulose acetate or hydroxypropyl cellulose, were acylated by CalB, as reported by Sereti and coworkers [53]. However, the same authors failed to modify crystalline cellulose under the same reaction conditions. 

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. 

Hydroxypropyl Cellulose occurs as a white powder. It is a cellulose ether containing hydroxypropyl substitution. It may contain a suitable anticaking agent. It is soluble in water and in certain organic solvents. 

Nakamura et al. ° studied the adhesion of water-soluble and neutral polymers, hydroxypropyl cellulose (HPC), xanthan gum (XG), tamarind gum (TG), and polyvinyl alcohol (PVA) to nasal mucosa in vitro and in vivo. The polymers, mixed with a dye, were applied as powders to the nasal cavity of rabbits, and the remaining dye residue was determined at 2, 4, and 6 h after nasal instillation with a thin fiberscope. The polymer XG showed the longest residence time of the dye in the cavity, followed by TG, HPC, and PVA in decreasing order. For the mixture XG and XG-PVA (2 8), some residue of dye could still be observed 6h after administration. The order of adhesion of these polymers to agar plates in vitro agreed with that of their mucoadhesion in vivo. Ilium et al. introduced bioadhesive microspheres for nasal delivery of poorly absorbable drugs. Radiolabelled microspheres made from diethylaminoethyl (DEAE)-dextran, starch microspheres, and albumin microspheres were administered to human volunteers and appeared to be cleared significantly slower than solutions or... 

Yamada, T. Saito, N. Imai, T. Otagiri, M. Effect of grinding with hydroxypropyl cellulose on the dissolution and particle size of a poorly water-soluble drug. Chem. Pharm. Bull. 1999, 47 (9), 1311-1313. 

Rowe, R.C. The prediction of compatibihty/incompatibility in blends of ethyl cellulose with hydroxypropyl methylcellulose or hydroxypropyl cellulose using 2-dimen-sional solubility parameter maps. J. Pharm. Pharmacol. 1986, 38, 214-215. 

Hydroxypropyl cellulose is produced by substituting propylene oxide for hydroxyl groups on alkalized cellulose. This cellulosic derivative is soluble in cold... 

Hydroxypropyl methylcellulose (HPMC) is produced similarly to hydroxypropyl cellulose except that methyl chloride is included in the reaction. The composition of the substituted hydroxyl groups ranges from 3% to 12% hydroxypropyl and from 19% to 30% methyl. HPMC is soluble in cold water and the polyethylene glycols up to 600 Da, but, in contrast to hydroxypropyl cellulose, HPMC is not soluble in alcohol. It is also less susceptible to hydrolysis, and is stable from pH 3 to 11. 

Increasing temperature causes the viscosity of aqueous solutions to decrease gradually until the viscosity drops suddenly at about 45°C owing to the limited solubility of hydroxypropyl cellulose. However, this process is reversible and on cooling the original viscosity is restored. 

Aqualon. Technical literature Klucel, hydroxypropyl cellulose, a nonionic water-soluble polymer, physical and chemical properties, 1987. 

Aqueous sodium chloride solutions are corrosive to iron. They also react to form precipitates with silver, lead, and mercury salts. Strong oxidizing agents liberate chlorine from acidified solutions of sodium chloride. The solubility of the antimicrobial preservative methylparaben is decreased in aqueous sodium chloride solutions and the viscosity of carbomer gels and solutions of hydroxyethyl cellulose or hydroxypropyl cellulose is reduced by the addition of sodium chloride. 

Hydroxypropyl 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. 

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. 

Methods of Preparation of Hydrophobically Modified WSPs (HMWSPs). Incorporation of Hydrophobes into WSPs. Water-soluble cellulose derivatives ((hydroxyethyl)cellulose, (hydroxypropyl)cellulose, methylcellulose, etc.) or synthetic polymers containing hydroxyl groups (e.g., poly(vinyl alcohol)) can be reacted with a long-chain alkyl halide (2), acyl halide (2), acid anhydride (6), isocyanate (2), or epoxide (2, 3) under appropriate conditions to form an HMWSP. These reactions are shown in Scheme I. These postmodifications can be done in solution or in hetero-... 

As with the alkylated polysaccharides, the physicochemical properties of hydroxyalkylated polysaccharides have continued to be investigated, particularly those of commercial value. The general characteristics of 0-(2-hydroxyethyl)cellulose have been described, together with pro-cedmes for the viscosimetric measurement of solutions of the polymer, and the macromolecular properties of the polymer in solution, described earlier, have been reviewed. The effect of increasing the substitution of both water-soluble 0-(2-hydroxyethyl)- and 0-(2-hydroxypropyl)-cellulose is to decrease their afiBnities for water. Water-soluble 0-(2-hy-droxypropyl) cellulose can be fractionated in a way analogous to that for O-methylcellulose by utilizing solvent—nonsolvent mixtures. For polysac-... 

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