Ph Eur
Action and use: Excipient.
DEFINITION
Partly or completely O-acetylated cellulose.
Content: 29.0 per cent to 44.8 per cent of acetyl groups (C2H3O) (dried substance) and 90.0 per cent to 110.0 per cent of the acetyl content stated on the label (dried substance).
CHARACTERS
Appearance: White, yellowish-white or greyish-white powder or granules, hygroscopic.
Solubility: Practically insoluble in water, soluble in acetone, in formic acid and in a mixture of equal volumes of methanol and methylene chloride, practically insoluble in alcohol.
IDENTIFICATION
Infrared absorption spectrophotometry.
TESTS
Free acid: Maximum 0.1 per cent, calculated as acetic acid (dried substance).
To 5.00 g in a 250 ml conical flask, add 150 ml of carbon dioxide-free water, insert the stopper, swirl the suspension gently and allow to stand for 3 h. Filter, wash the flask and the filter with carbon dioxide-free water. Combine the filtrate and washings. Add 0.1 ml of PhPh solution. Titrate with 0.01 M sodium hydroxide until a faint pink colour is obtained.
1 ml of 0.01 M sodium hydroxide is equivalent to 0.6005 mg of free acid, calculated as acetic acid.
Heavy metals: Maximum 10 ppm.
2.0 g complies with limit test D. Prepare the standard using 2 ml of lead standard solution (10 ppm Pb) R.
Loss on drying: Maximum 5.0 per cent, determined on 1.000 g by drying in an oven at 105C for 3 h.
Sulphated ash: Maximum 0.1 per cent, determined on 1.0 g.
Microbial contamination: Total viable aerobic count not more than 1000 micro-organisms per gram of which not more than 100 fungi per gram determined by plate count. It complies with the tests for Escherichia coli and Salmonella.
STORAGE
In an airtight container.
Cellulose, diacetate [9035-69-2].
Cellulose, triacetate [9012-09-3].
Cellulose Acetate is partially or completely acetylated cellulose. It contains not less than 29.0 percent and not more than 44.8 percent, by weight, of acetyl (C2H3O) groups, calculated on the dried basis. Its acetyl content is not less than 90.0 percent and not more than 110.0 percent of that indicated on the label.
Packaging and storage: Preserve in tight containers.
Labeling: The labeling states the nominal percentage content of acetyl.
Identification: Prepare a solution of Cellulose Acetate (1 in 10), previously dried, in dioxane. Spread 1 drop of the solution on a sodium chloride plate, place a second sodium chloride plate over it, and spread the specimen between the plates. Separate the plates, heat them both at 105C for 1 hour, and reassemble the dried plates: the IR absorption spectrum exhibits maxima only at the same wavelengths as that of a similar preparation of USP Cellulose Acetate RS, treated in the same manner.
Loss on drying: Dry it at 105C for 3 hours: it loses not more than 5.0% of its weight.
Residue on ignition: not more than 0.1%.
Heavy metals: 0.001%.
Free acid: Transfer about 5 g, accurately weighed, to a 250-mL flask. Add 150 mL of freshly boiled, cooled water, insert the stopper into the flask, swirl the suspension gently, and allow it to stand for 3 hours. Filter through paper, and wash the flask and the filter with water, adding these washings to the filtrate. Add PhPh, and titrate the combined filtrate and washings with 0.01 N sodium hydroxide. Calculate the percentage of free acid in the portion of Cellulose Acetate taken by the formula: 0.06005A/W in which A is the volume, in mL, of 0.01 N sodium hydroxide consumed; and W is the weight, in g, of the Cellulose Acetate taken, calculated on the dried basis. Not more than 0.1%, calculated as acetic acid, is found.
