C12H18N2O3 238.28

2,4,6(1H,3H,5H)-Pyrimidinetrione,5-(1-methylbutyl)-5-(2-propenyl)-.
5-Allyl-5-(1-methylbutyl)barbituric acid [76-73-3].

Packaging and storage— Preserve in tight containers.

USP Reference standards á11ñ— USP Secobarbital RS.

Identification,Infrared Absorption á197Mñ.

Loss on drying á731ñ— Dry it over silica gel for 18hours:it loses not more than 1.0%of its weight.

Residue on ignition á281ñ: not more than 0.1%.

Organic volatile impurities,Method Vá467ñ: meets the requirements.

Isomer content— Dissolve about 300±5mg in 5mLof sodium hydroxide solution (1in 100),add a solution of 300±5mg of p-nitrobenzyl bromide in 10mLof alcohol,reflux for 30minutes,cool,collect the precipitate on a small filter,and wash with water:the precipitate,recrystallized from 25mLof alcohol and dried at 105for 30minutes,melts between 156and 161.

Assay— Add about 450mg of Secobarbital,accurately weighed,to 60mLof dimethylformamide in a 125-mLconical flask.Add 4drops of thymol blue TS,and titrate with 0.1Nsodium methoxide VS,using a magnetic stirrer and taking precautions against the absorption of atmospheric carbon dioxide.Perform a blank determination,and make any necessary correction.Each mLof 0.1Nsodium methoxide is equivalent to 23.83mg of C12H18N2O3.

Expert Committee:(PA3)Pharmaceutical Analysis 3

USP28–NF23Page 1758

Phone Number:1-301-816-8330