Mephobarbital
;)
2,4,6(1H,3H,5H)-Pyrimidinetrione,5-ethyl-1-methyl-5-phenyl-.
5-Ethyl-1-methyl-5-phenylbarbituric acid [115-38-8].
»Mephobarbital contains not less than 98.0percent and not more than 100.5percent of C13H14N2O3,calculated on the dried basis.
Packaging and storage—
Preserve in well-closed containers.
Identification—
A:
Infrared Absorption á197Mñ.
B:
Boil about 200mg with 10mLof 1Nsodium hydroxide:ammonia is evolved.
C:
Shake about 60mg with 5mLof sodium hydroxide solution (1in 500),and filter.To a 1-mLportion of the filtrate add 3drops of mercuric nitrate TS:a white precipitate is formed,and it is soluble in 6Nammonium hydroxide.To another 1-mLportion of the filtrate add silver nitrate TS,dropwise:a white precipitate is formed,and it dissolves readily in 6Nammonium hydroxide.
Loss on drying á731ñ—
Dry it at 105
for 4hours:it loses not more than 1.0%of its weight.
for 4hours:it loses not more than 1.0%of its weight.
Residue on ignition á281ñ:
not more than 0.1%.
Organic volatile impurities,Method IVá467ñ:
meets the requirements.
Assay—
Dissolve about 500mg of Mephobarbital,accurately weighed,in 50mLof dimethylformamide in a 200-mLflask.Add 4drops of thymolphthalein TS,and titrate with 0.1Nlithium methoxide VS,using a magnetic stirrer and a cover for the flask to protect against atmospheric carbon dioxide.Perform a blank determination,and make any necessary correction.Each mLof 0.1Nlithium methoxide is equivalent to 24.63mg of C13H14N2O3.
Auxiliary Information—
Staff Liaison:Ravi Ravichandran,Ph.D.,Senior Scientist
Expert Committee:(PA3)Pharmaceutical Analysis 3
USP28–NF23Page 1211
Pharmacopeial Forum:Volume No.30(5)Page 1634
Phone Number:1-301-816-8330