Packaging and storage— Preserve in Containers for Sterile Solidsas described under Injections á1ñ,protected from direct sunlight.Store at controlled room temperature.

Labeling— The package bears a statement to the effect that the sterility of Oxidized Regenerated Cellulose cannot be guaranteed if the package bears evidence of damage,or if the package has been previously opened.Oxidized Regenerated Cellulose meets the requirements for Labelingunder Injections á1ñ.

Identification— To about 200mg add 10mLof 0.25Nsodium hydroxide,and shake for 1minute.Add 10mLof 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 10minutes:any swollen fibers initially present are no longer visible.Acidify with 3Nhydrochloric acid:a flocculent white precipitate is formed.

Sterility á71ñ: meets the requirements;the test specimen weighing approximately 250mg and 0.5mLof 0.1Nsodium hydroxide being added to the portions of media used.

Loss on drying á731ñ— Dry about 150mg at 90for 2hours:it loses not more than 15%of its weight.

Residue on ignition á281ñ: not more than 0.15%.

Nitrogen content— Transfer about 1g,previously dried and accurately weighed,to a 500-mL Kjeldahl flask.Arrange a 125-mLconical flask,containing 30mLof boric acid solution (1in 25)and 6drops of mixed indicator (1part of methyl red TSand 4parts 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 1g of Devarda's alloy,100mLof recently boiled water,a small lump of paraffin,and 100mLof 1Nsodium hydroxide.Connect the Kjeldahl flask to the condenser by a suitable trap bulb.Heat the mixture in the flask until 45to 50mLof distillate has collected in the receiver.Rinse the condenser,and titrate the boric acid solution with 0.02Nsulfuric acid VSto a pale pink endpoint that persists for 30seconds.Perform a blank determination,and make any necessary correction.Each mLof 0.02Nsulfuric acid is equivalent to 0.2801mg of nitrogen.The nitrogen content does not exceed 0.5%.

Formaldehyde— Transfer 500mg to a 500-mLiodine flask.Add 250mLof water,and allow to stand for not less than 2hours with intermittent shaking.Pipet 0.5mLof the supernatant into a glass-stoppered test tube,and add 10mLof chromotropic acid TS.Stopper the tube loosely,and heat in a boiling water bath for 30minutes.Cool,and determine the absorbance of the solution at 570nm,with a suitable spectrophotometer,using a mixture of 0.5mLof water and 10mLof chromotropic acid TSas the blank:the absorbance does not exceed that produced when 0.5mLof dilute formaldehyde solution (1in 40,000)is treated in the same manner (0.5%CH2O).

Assay— Transfer about 1g of Oxidized Regenerated Cellulose,previously dried at 90for 2hours and accurately weighed,to a 250-mLconical flask.Pipet 10mLof 0.5Nsodium hydroxide VSinto the flask,swirl to dissolve,and add 100mLof water.Immediately titrate with 0.1Nhydrochloric acid VSto a phenolphthalein endpoint.Perform a blank determination,and note the difference in volumes required.Each mLof the difference in volumes of 0.1Nhydrochloric acid consumed is equivalent to 4.50mg of carboxyl (COOH).

Expert Committee:(GTB)General Toxicology and Biocompatibility

USP28–NF23Page 411

Phone Number:1-301-816-8339