Carbonic acid,monoammonium salt,mixt.with ammonium carbamate.
Monoammonium carbonate mixture with ammonium carbamate [8000-73-5].

Packaging and storage— Preserve in tight,light-resistant containers,at a temperature not above 30.

Identification— When heated,it is volatilized without charring,and the vapor is alkaline to moistened litmus paper.Asolution (1in 20)effervesces with acids.

Residue on ignition á281ñ: not more than 0.1%.

Chloride á221ñ— A2.0-g portion shows no more chloride than corresponds to 0.10mLof 0.020Nhydrochloric acid (0.0035%).

Sulfate á221ñ— A2.0-g portion shows no more sulfate than corresponds to 0.10mLof 0.020Nsulfuric acid (0.005%).

Heavy metals,Method Iá231ñ— Reduce to a coarse powder and volatilize 2g of it on a steam bath.Add to the residue 1mLof 3Nhydrochloric acid,and evaporate to dryness.Dissolve the residue in 2mLof 1Nacetic acid,and add water to make 25mL:the limit is 0.001%.

Assay— Place in a weighing bottle about 10mLof water,tare the bottle and its contents,add about 2g of Ammonium Carbonate,and weigh accurately.Transfer the contents of the bottle to a 250-mLflask,add 50.0mLof 1Nsulfuric acid VS,and,when solution has been effected,add methyl orange TS,and titrate the excess acid with 1Nsodium hydroxide VS.Perform a blank determination (see Residual Titrations underTitrimetry á541ñ).Each mLof 1Nsulfuric acid is equivalent to 17.03mg of NH3.

Expert Committee:(EMC)Excipients:Monograph Content

USP28–NF23Page 2956

Phone Number:1-301-816-8262