Labeling—
The package bears a statement to the effect that the sterility of Oxidized Cellulose cannot be guaranteed if the package bears evidence of damage, or if the package has been previously opened. Oxidized Cellulose meets the requirements for
Labeling under
Injections 
1
.
Identification—
To about 200 mg add 10 mL of 0.25 N sodium hydroxide, and shake for 1 minute. Add 10 mL of water, and shake: the solution so obtained shows no more than a slight haze and is substantially free from fibers and from foreign particles. Allow to stand for 10 minutes: any swollen fibers initially present are no longer visible. Acidify with 3 N hydrochloric acid: a flocculent white precipitate is formed.
Sterility 71—
It meets the requirements, the test specimen weighing approximately 250 mg and 0.5 mL of 0.1 N sodium hydroxide being added to the portions of media used.
Loss on drying 731—
Dry it in vacuum over phosphorus pentoxide for 18 hours: it loses not more than 15.0% of its weight.
Limit of nitrogen—
Transfer about 1 g, previously dried in vacuum over phosphorus pentoxide for 18 hours and accurately weighed, to a 500-mL Kjeldahl flask. Arrange a 125-mL conical flask, containing 30 mL of boric acid solution (1 in 25) and 6 drops of mixed indicator (1 part of
methyl red TS and 4 parts of
bromocresol green TS), beneath the condenser of the distillation apparatus so that the tip of the condenser is well below the surface of the boric acid solution. To the Kjeldahl flask containing the sample add 1 g of Devarda's alloy, 100 mL of recently boiled water, a small lump of paraffin, and 100 mL of 1 N sodium hydroxide. Connect the Kjeldahl flask to the condenser by a suitable trap bulb. Heat the mixture in the flask until 45 to 50 mL of distillate has collected in the receiver. Rinse the condenser, and titrate the boric acid solution with 0.02 N sulfuric acid VS to a pale pink endpoint. Perform a blank determination, and make any necessary correction. Each mL of 0.02 N sulfuric acid is equivalent to 0.2801 mg of nitrogen. The nitrogen content does not exceed 0.5%.
Limit of formaldehyde—
Weigh accurately about 500 mg, and transfer to a 500-mL iodine flask. Add 250 mL of water, and allow to stand for not less than 2 hours with intermittent shaking. Pipet 0.50 mL of the supernatant into a glass-stoppered test tube, and add 10 mL of
chromotropic acid TS. Stopper the tube loosely, and heat in a boiling water bath for 30 minutes. Cool, and determine the absorbance of the solution at 570 nm, with a suitable spectrophotometer, using a mixture of 0.5 mL of water and 10 mL of
chromotropic acid TS as the blank: the absorbance does not exceed that produced when 0.50 mL of dilute formaldehyde solution (1 in 40,000) is treated in the same manner (0.5%).
Assay—
Transfer about 500 mg of Oxidized Cellulose, previously dried over phosphorus pentoxide in vacuum for 18 hours and accurately weighed, to a 125-mL conical flask. Add 50.0 mL of calcium acetate solution (1 in 50), swirl until the sample is completely covered, allow the mixture to stand for 30 minutes, then add
phenolphthalein TS, and titrate the solution with 0.1 N sodium hydroxide VS. Perform a blank determination by titrating 50.0 mL of the calcium acetate solution, and make any necessary correction. Each mL of 0.1 N sodium hydroxide is equivalent to 4.502 mg of carboxyl groups (COOH).
