Neostigmine Methylsulfate
C13H22N2O6S
334.39
Benzenaminium,3-[[(dimethylamino)carbonyl]oxy]-N,N,N-trimethyl-,methyl sulfate.
(m-Hydroxyphenyl)trimethylammonium methyl sulfate dimethylcarbamate [51-60-5].
»Neostigmine Methylsulfate contains not less than 98.0percent and not more than 102.0percent of C13H22N2O6S,calculated on the dried basis.
Packaging and storage—
Preserve in tight containers.
Identification—
A:
Infrared Absorption á197Kñ.
B:
Place about 1mg in a small porcelain dish,add 2mLof water and 0.5mLof sodium hydroxide solution (2in 5),and evaporate on a steam bath to dryness.Transfer the residue to a small test tube,and quickly heat in a suitable liquid bath to 250
,continuing at that temperature for about 30seconds.Cool,dissolve the residue in 0.5mLof water,cool in ice water,and add 1mLof diazobenzenesulfonic acid TS:a cherry-red color is produced.
,continuing at that temperature for about 30seconds.Cool,dissolve the residue in 0.5mLof water,cool in ice water,and add 1mLof diazobenzenesulfonic acid TS:a cherry-red color is produced.
C:
Mix about 20mg with 500mg of sodium carbonate,and heat the mixture to fusion in a small crucible.Boil the fused mass with 10mLof water until disintegrated,and filter.Add a few drops of bromine TSto the filtrate,heat to boiling,acidify with hydrochloric acid,and expel the excess bromine by boiling:the resulting solution responds to the tests for Sulfate á191ñ.
Loss on drying á731ñ:
Dry about 300mg,accurately weighed,at 105for 3hours:it loses not more than 1.0%of its weight.
for 3hours:it loses not more than 1.0%of its weight.
Residue on ignition á281ñ:
not more than 0.1%.
Chloride—
To 10mLof a solution (1in 50)add 1mLof 2Nnitric acid and 1mLof silver nitrate TS:no opalescence is produced immediately.
Sulfate ion—
To 10mLof a solution (1in 50)add 1mLof 3Nhydrochloric acid and 1mLof barium chloride TS:no turbidity is produced immediately.
Assay—
Place about 100mg of Neostigmine Methylsulfate,accurately weighed,in a 500-mL Kjeldahl flask,dissolve in 150mLof water,and add 40mLof 2.5Nsodium hydroxide.Connect the flask by means of a distillation trap to a well-cooled condenser that dips into 25mLof boric acid solution (1in 25),distill about 150mLof the contents of the flask,add methyl purple TSto the solution in the receiver,and titrate with 0.02Nsulfuric acid VS.Perform a blank determination,and make any necessary correction.Each mLof 0.02Nsulfuric acid is equivalent to 6.688mg of C13H22N2O6S.
Auxiliary Information—
Staff Liaison:Ravi Ravichandran,Ph.D.,Senior Scientist
Expert Committee:(PA3)Pharmaceutical Analysis 3
USP28–NF23Page 1365
Pharmacopeial Forum:Volume No.29(6)Page 1936
Phone Number:1-301-816-8330