Name: Cellulose, Microcrystalline and Carboxymethylcellulose Sodium
CAS No: See Section 8.
BP: Dispersible Cellulose PhEur: Microcrystalline Cellulose and Carmellose Sodium USP-NF: Microcrystalline Cellulose and Carboxymethylcellulose Sodium
Avicel CL-611; Avicel RC-501; Avicel RC-581; Avicel RC-591; Avicel RC/CL; cellulosum microcristallinum et carmellosum natricum; colloidal cellulose; Vivapur MCG 591 PCG; Vivapur MCG 611 PCG.
See Section 8.
See Section 8.
See Section 8.
Microcrystalline cellulose and carboxymethylcellulose sodium is used to produce thixotropic gels suitable as suspending vehicles in pharmaceutical and cosmetic formulations. The sodium carboxymethylcellulose aids dispersion and serves as a protective colloid. Concentrations of less than 1% solids produce fluid dispersions, while concentrations of more than 1.2% solids produce thixotropic gels. When properly dispersed, it imparts emulsion stability, opacity and suspension in a variety of products, and is used in nasal sprays, topical sprays and lotions, oral suspensions, emulsions, creams(1) and gels.
Microcrystalline cellulose and carboxymethylcellulose sodium occurs as a white or off-white odorless and tasteless hygroscopic powder containing 5–22% sodium carboxymethylcellulose. It is a water-dispersible organic hydrocolloid.
See Table I. See also Section 18
Acidity/alkalinity pH 6–8 for a 1.2% w/v aqueous dispersion. Density (bulk) 0.6 g/cm3 Microbial content Total aerobic microbial count 4100 cfu/g for Avicel RC/CL (Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa and Salmonella species absent); total yeast and mold count 420 cfu/g for Avicel RC/CL. Moisture content Not more than 6.0% w/w Particle size distribution Avicel CL-611: 40.1% retained on a #60 mesh and 450% retained on a #325 mesh; Avicel RC-581: 40.1% retained on a #60 mesh and 435% retained on a #200 mesh; Avicel RC-591: 40.1% retained on a #60 mesh and 445% retained on a #325 mesh; Vivapur MCG 591 PCG: 45% retained on a #30 mesh and 450% retained on a #60 mesh; Vivapur MCG 611 PCG: 45% retained on a #30 mesh and 450% retained on a #60 mesh. Sodium content 0.8% for Avicel RC-581 and Avicel RC-591; 1.2% for Avicel CL-611. Solubility Practically insoluble in dilute acids and organic solvents. Partially soluble in dilute alkali and water (carboxymethylcellulose sodium fraction). Viscosity (dynamic) (1.2% w/v aqueous dispersion) 50–118 mPa s (50–118 cP) for Avicel CL-611 72–168 mPa s (72–168 cP) for Avicel RC-581 39–91 mPa s (39–91 cP) for Avicel RC-591 39–91 mPa s (39–91 cP) for Vivapur MCG 591 PCG 50–118 mPa s (50–118 cP) for Vivapur MCG 611 PCG
Microcrystalline cellulose and carboxymethylcellulose sodium is hygroscopic and should not be exposed to moisture. It is stable over a pH range of 3.5–11. Store in a cool, dry place. Avoid exposure to excessive heat.
Microcrystalline cellulose and carboxymethylcellulose sodium is incompatible with strong oxidizing agents. See Cellulose, Microcrystalline, and Carboxymethylcellulose Sodium
Microcrystalline cellulose and carboxymethylcellulose sodium is a spray- or bulk-dried blend of microcrystalline cellulose and sodium carboxymethylcellulose. It is prepared by the chemical depolymerization of highly purified wood pulp. The original crystalline areas of the pulp fibers are combined with sodium carboxymethylcellulose, which serves as a protective colloid and also facilitates dispersion of the product; it is then either spray- or bulk-dried.
Microcrystalline cellulose and carboxymethylcellulose sodium is used in a wide range of pharmaceutical formulations and has low oral, dermal and inhalation toxicity. It is nonirritating to the eyes and skin, and nonsensitizing to the skin. No significant acute toxicological effects are expected. LD50 (skin, rabbit): >2.0 g/kg LD50 (oral, rat): >5.0 g/kg For further safety information, see Cellulose, Microcrystalline, and Carboxymethylcellulose Sodium.
Observe normal precautions appropriate to the circumstances and quantity of material handled. Eye protection is recommended. See also Cellulose, Microcrystalline, and Carboxymethylcellulose Sodium.
Microcrystalline cellulose and carboxymethylcellulose sodium is a mixture of two materials both of which are generally regarded as nontoxic: Microcrystalline cellulose GRAS listed. Accepted for use as a food additive in Europe. Included in the FDA Inactive Ingredients Database (inhalations; oral capsules, powders, suspensions, syrups, and tablets; topical and vaginal preparations). Included in nonparenteral medicines licensed in the UK. Included in the Canadian List of Acceptable Non-medicinal Ingredients. Carboxymethylcellulose sodium GRAS listed. Accepted as a food additive in Europe. Included in the FDA Inactive Ingredients Database (dental preparations; intra-articular, intrabursal, intradermal, intralesional, and intrasynovial injections; oral drops, solutions, suspensions, syrups and tablets; topical preparations). Included in nonparenteral medicines licensed in the UK. Included in the Canadian List of Acceptable Nonmedicinal Ingredient
Cellulose, microcrystalline; carboxymethylcellulose sodium
Microcrystalline cellulose is one of the materials that have been selected for harmonization by the Pharmacopeial Discussion Group. For further information see the General Information Chapter <1196> in the USP32–NF27, the General Chapter 5.8 in PhEur 6.0, along with the ‘State of Work’ document on the PhEur EDQM website, and also the General Information Chapter 8 in the JP XV The properties of preparations containing microcrystalline cellulose and carboxymethylcellulose sodium depend on the development of maximum colloidal dispersions in water.(2,3) Avicel RC/CL dispersions yield a highly thixotropic vehicle, which is primarily the result of the large number of colloidal microcrystal particles that result from full dispersion in aqueous media. The network establishes a weak gel structure with a measurable yield point that prevents drug particles from settling in a formulation. This gel structure is easily broken by mild shaking to yield a readily pourable liquid. Upon removal of shear, the gel structure reestablishes, providing a suspension medium with long-term stability against phase separation. Avicel RC-591 has been found to have optimal formulation properties compared with other suspending agents in metronidazole benzoate suspensions.(4) A specification for microcrystalline cellulose and carmellose sodium is contained in the Japanese Pharmaceutical Excipients (JPE).(5)