Cellulose, carboxymethyl ether, calcium salt.
Cellulose carboxymethyl ether calcium salt [9050-04-8].

Packaging and storage— Preserve in tight containers.

Identification—

Alkalinity— Shake thoroughly 1.0 g with 50 mL of freshly boiled and cooled water, and add 2 drops of phenolphthalein TS: no red color develops.

Loss on drying 731— Dry it at 105º for 4 hours: it loses not more than 10.0% of its weight.

Residue on ignition 281: between 10.0% and 20.0%, about 1.0 g, previously dried, being used for the test.

Heavy metals 231— Determine as directed in the test for Heavy metals under Methylcellulose, except to use only 1 g of Carboxymethylcellulose Calcium. The limit is 0.002%.

Limit of chloride 221— Shake thoroughly 0.80 g with 50 mL of water, dissolve in 10 mL of 1 N sodium hydroxide, add water to make 100 mL, and use 20 mL of this solution as the test solution, retaining the remainder of it for the test for Limit of sulfate. Heat 20 mL of the test solution with 10 mL of 2 N nitric acid in a water bath until a flocculent precipitate is formed, cool, centrifuge, and remove the supernatant. Wash the precipitate with three 10-mL portions of water by centrifuging each time, combine the supernatant and the washings, add water to make 100 mL, and mix: a 25-mL portion of this solution shows no more chloride than is contained in 0.20 mL of 0.020 N hydrochloric acid (0.36%).

Limit of sulfate 221— Heat 10 mL of the test solution obtained in test for Limit of chloride with 1 mL of hydrochloric acid in a water bath until a flocculent precipitate is formed, cool, centrifuge, and remove the supernatant. Wash the precipitate with three 10-mL portions of water by centrifuging each time, combine the supernatant and the washings, add water to make 100 mL, and mix: a 25-mL portion of this solution shows no more sulfate than is contained in 0.21 mL of 0.020 N sulfuric acid (1.0%).

Expert Committee : (EM205) Excipient Monographs 2

USP29–NF24 Page 3300

Phone Number : 1-301-816-8351