Hydroxypropylcellulose properties

Properties. Hydroxypropylcellulose [9004-64-2] (HPC) is a thermoplastic, nonionic cellulose ether that is soluble in water and in many organic solvents. HPC combines organic solvent solubiUty, thermoplasticity, and surface activity with the aqueous thickening and stabilising properties characteristic of other water-soluble ceUulosic polymers described herein. Like the methylceUuloses, HPC exhibits a low critical solution temperature in water. 

An erodible insert developed as a potential ocular drug-delivery system is marketed as a prescription drug for the lubricant properties of the polymer base. Lacrisert is a sterile ophthalmic insert used in the treatment of moderate to severe dry eye syndrome and is usually recommended for patients unable to obtain symptomatic relief with artificial tear solutions. The insert is composed of 5 mg of hydroxypropylcellulose in a rod-shaped form about 1.27 mm diameter by about 3.5 mm long. No preservative is used, since it is essentially anhydrous. The quite rigid cellulose rod is placed in the lower conjunctival sac and first imbibes water from the tears and after several hours forms a... 

These stabilizers are added to the formulation in order to stabilize the emulsion formed during particle preparation. These stabilizers, however, can also influence the properties of the particles formed. The type and concentration of the stabilizer selected may affect the particle size. Being present at the boundary layer between the water phase and the organic phase during particle formation, the stabilizer can also be incorporated on the particle surface, modifying particle properties such as particle zeta potential and mucoadhesion (203). Other polymers have also been evaluated as stabilizers in earlier studies such as cellulosic derivatives methylcellu-lose (MC), hydroxyethylcellulose ( ), hydroxypropylcellulose (HPC), and hydroxypropylmethylcellulose (HPMC), as well as gelatin type A and B, carbomer and poloxamer (203). 

Aqualon Company (1987). Klucel Hydroxypropylcellulose. Physical and Chemical Properties. Report 250-2C Rev. 10-87 15M IP. Aqualon Company, Wilmington, DE. 

A popular approach to improve ocular drag bioavailability is to incorporate soluble polymers into an aqueous solution to extend the drug residence time in the cul-de-sac. It is reasoned that the solution viscosity would be increased and hence solution drainage would be reduced. The more commonly used viscolyzing agents include PVA and derivatives of cellulose. Cellulosic polymers, such as methylcellulose, hydroxyethylcellulose (HEC), hydroxypropyl-methylcellulose (HPMC) and hydroxypropylcellulose (HPC), are widely used as viscolyzers showing Newtonian properties. They have common properties ... 

Chemical modification of hydroxyethylcellulose or hydroxypropylcellulose with long-chain hydrocarbon alkylating reagents, such as C8-C24 epoxides or halides, has been reported to yield novel water-soluble compositions exhibiting enhanced low-shear-rate solution viscosities and polymeric surfactant properties [ 104,105]. Patents have also been issued for water-soluble phosphonomethylcellulose and phosphonomethylhydroxyethylcellulose [106,107]. 

Repka, M.A. Gerding, T.G. Repka, S.L. McGinity, J.W. Influence of plasticizers and drugs on the physical-mechanical properties of hydroxypropylcellulose films prepared by hot-melt extmsion. Drug Dev. Ind Pharm. 1999,25 (5), 627-635. 

Klucel Hydroxypropylcellulose physical and chemical properties. In Technical Bulletin Hercules, Inc. Wilmington, DE, 1997. 

The same group has also obtained composite materials based on imogolite and water-soluble polymers such as hydroxypropylcellulose (HPC) and poly (vinylalcohol) (PVA) [32]. HPC is a rigid rod polymer that has a cholesteric phase, whereas PVA is a random coil amorphous polymer. Significantly enhanced mechanical properties were only obtained in the case of the HPC composite materials. 

Table 1.3 shows, for example, the surface tension of the solutions of some water-soluble polymers at 25°C (0.1% aqueous solutions of the polymers). Hydroxypropylcellulose (HPC) is a good example of a surface-active polymer. Water solutions greatly reduced surface and interfacial tensions. HPC functions as an assistant in both emulsifying and whipping. HPC combines organic solvent solubility, thermoplasticity and surface activity with the aqueous thickening and stabilizing properties of other water soluble cellulose pol miers. 

The hydration properties of 2,3-O-hydroxypropylcellulose and 2,3-0-hydroxyethylcellulose were analyzed by multi-nuclear solid-state NMR spectroscopy. CPMAS and SPMAS in combination with NMR were carried out. Differences in mobile and immobile region within the polymers were determined. 

An ester of cellulose, the hydroxypropylcellulose (HPC), was chosen among the several cellulosic derivatives which can be used as matrix materials. HPC is readily available, inexpensive and soluble in a wide variety of common organic solvents. As reinforcement, Avicel fibers (/ = 30 pm and Ijd = 5) were used. Cross-linking was achieved using several aliphatic or aromatic diisocyanates [13]. It is worth mention that general trends concerning the mechanical and gas barrier properties were similar for all cross-linked composites, and for that reason we refer to those that have been cross-linked with 1,4-butyldiisocyanate (BDI). 

Borges JP, Godinho MH et al (2004) Tensile properties of cellulose fiber reinforced hydroxypropylcellulose films. Polym Compos 25 102-110... 

Mixtures of hydrocoUoidal gelling agents in an aqueous medium have also been employed as water-soluble or water-dispersible additives to provide gels having solids-suspending properties. Such mixtures include a mixture of hydroxypropyl-cellulose and poly(l-alkene-maleic anhydride) as poly(isobutylene-co-maleic anhydride), and a blend of hydroxypropylcellulose and poly(alkyl vinyl ether-co-maleic anhydride) as poly(methyl vinyl ether-co-maleic anhydride) [91]. 

The following commercially available polymer samples were used as received poly(vinyl alcohol), PVA (Polyviol, Wacker Chemie GmbH) hydroxypropylcellulose, HPC (Klucel, Hercules Inc.) poly(acrylic acid), PAA (Carbopol 940, Goodrich Chemical Co.). Some properties of the polymers are reported in Table 1. 

K.M. Picker-Freyer, T. Diirig, Physical mechanical and tablet formation properties of hydroxypropylcellulose In pure form and in mixtures, AAPS PharmSciTech, 8 (4), 2007. 

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