Hydroxypropylcellulose

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. 

The observed release rates declined with time consistent with a monolithic formulation. Fluridone release for 20-40 days was achieved by adjustment of the pellet dimensions, the surface-to-volume ratio, and the hydroxypropylcellulose PCL ratio. 

The viscosity of an emulsion can be of crucial importance for its stability, especially the viscosity of the external phase. A high viscosity reduces creaming and also lessens the tendency of particles to coalescence and produce phase separation. Examples of the widely used viscosity-imparting agents are alginates, bentonite, carboxymethylcellulose, polyvinyl pyrrolidone, hydroxypropylcellulose, and carbomer. 

Hydroxypropylcellulose HPC Cold water, GI fluids, polar organics such as anhydrous lower alcohols Difficulty in handling due to tackiness while drying... 

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... 

Since all the derivatives studied, except (III), had a very poor solubility in water (<2 g/1), they were inoculated as suspensions in 4% hydroxypropylcellulose (Klucel J. F., Hercules Co) solutions in water. Such Klucel solutions were shown to be nontoxic after i.p. (intra-peritoneal) inoculation. Moreover, the size of the molecular aggregates in such Klucel solution was much less than 1 pm, as demonstrated by electron microscopy. 

SOF, SOPHi and SOAz are soluble in water and could consequently by used in 0.9% NaCl water solution for both toxicity measurements and antitumoral tests DISOF, having very poor solubility in water, was inoculated as a suspension in 4 0 aqueous hydroxypropylcellulose (Klucel J. F. Hercules Co.). 

Hydroxypropylcellulose (HPC) is a thermoplastic nonionic cellulose ester that is soluble in both water and a number of organic liquids. It is synthesized through reaction of the basic cellulose slurried with propylene oxide. 

Dapiprazole base, DAP-B (melting point, 163-164°C), and hydrochloride, DAP-HCL (melting point, 192-193°C), were purified samples supplied by Acraf SpA (Ancona) high molecular weight hydroxypropylcellulose, HPC (Klucel HF, Her-cules Inc., Wilmington, DE), and polyglacturonic acid, PGA (4.89 mEq/g, Prion Chemicals, Milano), were commercial samples, used without prior purification. Benzalkonium chloride, USP grade (BZ), was purchased from Carlo Erba SpA Nylon 6 (Capran 77C, thickness 27 0.3 pm) was obtained from Allied Chemical Corp., Morristown, NJ. 

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). 

Granulate the mixture by agitation while spraying it with a binder of hydroxypropylcellulose and yellow no. 5 in water. 

Each 5 mL of VANTIN oral suspension contains cefpodoxime proxetil equivalent to 50 mg or 100 mg of cefpodoxime activity after constitution and the following inactive ingredients artificial flavorings, butylated hydroxy anisole, carboxymethylcellulose sodium, microcrystalline cellulose, carrageenan, citric acid, colloidal silicon dioxide, croscarmellose sodium, hydroxypropylcellulose, lactose, maltodextrin, natural flavorings, propylene glycol... 

In general, the MS controls the solubility of both HEC and HPC. For example, water-soluble grades of hydroxyethylcellulose have MS values of 1.6—3.0 those with MS 0.3—1.0 are soluble in aqueous alkali. Even higher MS types of hydroxypropylcellulose become soluble in oiganic solvents, first polar, then nonpolar solvents. 

Clear, water-soluble, oil-and grease-resistant films of moderate strength can be cast from hydroxyethylcellulose solutions. Flexible, nontacky, heat-sealable packaging films and sheets can be produced from hydroxypropylcellulose by conventional extrusion techniques. Both gums can be used in the formulation of coatings, and both can be used to form edible films and coatings. 

H. Yokota, Alkalization mechanism of cellulose in hydroxypropylcellulose preparation process, J. Appl. Polym. Sci., 32 3423 (1986). 

Figure 2 illustrates the temperature dependence of the swelling degree as a function of precursor polymer type. Methylcellulose (MC), hydroxypropyl-methylcellulose, type E (HPMC-E) and hydroxypropylmethylcellulose, type K (HPMC-K) gels have comparable effective crosslink densities of about 2 x 10 5 mol/cm3 (as determined from uniaxial compression testing), while the crosslink density of the hydroxypropylcellulose (HPC) gel is about half this [52]. The transition temperature for each gel is within several degrees of the precursor polymer lower critical solution temperature (LCST), except for the MC gel, which has a transition temperature 9 °C higher than the LCST. The sharpness of the transition was about 3%/°C, except for the HPC gel transition, which was much sharper - about 8%/°C. 

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