Content uniformity test of tablets by nonaqueous titration method.

For the Content uniformity test (CUT) of tablets where the active drug behaves in a nonaqueous medium as a base a very simple method was developed. This method is based on the extraction of the active drug from the tablet into anhydrous acetic acid and direct titration of the solute with HClO4 (0.1 or 0.05 mol/l solution in anhydrous acetic acid). The course of the titration is followed potentiometrically with a glass and calomel electrode coupled and recorded automatically with a suitable registration potentiometer. The method was successfully applied to samples of commercial tablets containing the following drugs: codeine phosphate, embramine, ephedrine, ethylmorphine, pyridoxine, thiamine and tolazoline, all as hydrochlorides. It can be used also for several other drugs.