U.S. PHARMACOPEIA

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Powdered Cellulose
» Powdered Cellulose is purified, mechanically disintegrated cellulose prepared by processing alpha cellulose obtained as a pulp from fibrous plant materials.
Packaging and storage— Preserve in tight containers.
Labeling— The labeling indicates the nominal degree of polymerization value. Degree of polymerization compliance is determined using Identification test B.
Identification—
A: Prepare iodinated zinc chloride solution by dissolving 20 g of zinc chloride and 6.5 g of potassium iodide in 10.5 mL of water. Add 0.5 g of iodine, and shake for 15 minutes. Place about 10 mg of Powdered Cellulose on a watch glass, and disperse in 2 mL of iodinated zinc chloride solution: the substance takes on a violet-blue color.
B: Transfer 0.25 g of Powdered Cellulose, accurately weighed to 0.1 mg, to a 125-mL conical flask. Add 25.0 mL of water and 25.0 mL of 1.0 M cupriethylenediamine hydroxide solution. Immediately purge the solution with nitrogen, insert the stopper, and shake on a wrist action shaker or other suitable mechanical shaker until completely dissolved. Transfer 7.0 mL of the solution to a calibrated number 150 Cannon-Fenske, or equivalent, viscosimeter. Allow the solution to equilibrate at 25 ± 0.1 for not less than 5 minutes. Time the flow between the two marks on the viscosimeter, and record the flow time, t1, in seconds. Calculate the kinematic viscosity, (KV)1, of the Powdered Cellulose taken by the formula:
t1(k1),
in which k1 is the viscosimeter constant (see Viscosity 911). Obtain the flow time, t2, for a 0.5 M cupriethylenediamine hydroxide solution using a number 100 Cannon-Fenske, or equivalent, viscosimeter. Calculate the kinematic viscosity, (KV)2, of the solvent by the formula:
t2(k2),
in which k2 is the viscosimeter constant. Determine the relative viscosity, rel, of the Powdered Cellulose specimen taken by the formula:
(KV)1 / (KV)2.
Determine the intrinsic viscosity, []c, by interpolation, using the Intrinsic Viscosity Table in the Reference Tables section. Calculate the degree of polymerization, P, by the formula:
(95)[]c / WS[(l00 – %LOD)/100],
in which WS is the weight, in g, of the Powdered Cellulose taken; and %LOD is the value obtained from the test for Loss on drying. The degree of polymerization is greater than 440.
Microbial limits 61— The total aerobic microbial count does not exceed 1000 cfu per g, the total combined molds and yeasts count does not exceed 100 cfu per g, and it meets the requirements of the tests for absence of Staphylococcus aureus and Pseudomonas aeruginosa and for absence of Escherichia coli and Salmonella species.
pH 791— Mix 10 g with 90 mL of water, and allow to stand with occasional stirring for 1 hour: the pH of the supernatant is between 5.0 and 7.5.
Loss on drying 731— Dry it at 105 for 3 hours: it loses not more than 6.5% of its weight.
Residue on ignition 281: not more than 0.3%, calculated on the dried basis.
Water-soluble substances— Mix 6.0 g with 90 mL of recently boiled and cooled water, and allow to stand with occasional stirring for 10 minutes. Filter, with the aid of vacuum, discard the first 10 mL of the filtrate, and pass the filtrate through the same filter a second time, if necessary, to obtain a clear filtrate. Evaporate a 15.0-mL portion of the filtrate in a tared evaporating dish to dryness without charring, dry at 105 for 1 hour, cool in a desiccator, and weigh: the difference between the weight of the residue and the weight obtained from a blank determination does not exceed 15.0 mg (1.5%).
Ether-soluble substances— Place 10.0 g in a chromatography column having an internal diameter of about 20 mm, and pass 50 mL of peroxide-free ether through the column. Evaporate the eluate to dryness in a previously dried and tared evaporating dish with the aid of a current of air in a fume hood. After all the ether has evaporated, dry the residue at 105 for 30 minutes, cool in a desiccator, and weigh: the difference between the weight of the residue and the weight obtained from a blank determination does not exceed 15.0 mg (0.15%).
Residual solvents 467: meets the requirements.
(Official January 1, 2007)
Auxiliary Information— Staff Liaison : Hong Wang, Ph.D. , Senior Scientific Associate
Expert Committee : (EM205) Excipient Monographs 2
USP29–NF24 Page 3308
Pharmacopeial Forum : Volume No. 31(5) Page 1421
Phone Number : 1-301-816-8351