Nonaqueous titration of barbiturates in tetramethylurea.

Tetramethylurea was evaluated as a solvent for the nonaqueous titration of barbiturates and several of their dosage forms and combinations. Tetrabutylammonium hydroxide and sodium methoxide in benzene-methanol were used as titrants. Titrations were performed visually and potentiometrically with a titrimeter equipped with a glass-calomel electrode system. Comparison was made with the solvent dimethylformamide.