Quantitative determination of weak acidic drugs by gran's method

Abstract

Potentiometric titrations of weak acidic drugs with strong base, Gran's second method could yield end point volumes with the same degree of accuracy and reproducibility as non-aqueous titration methods which are described in USP XXI. Gran's method gave satisfactory results even when the unionized drugs precipitated out of solutions during the course of titrations. Mixed solvent of 40% v/v ethanol/water was utilized in order to increase the solubilities of the precipitates. In this case Gran's method was still employed advantageously for the end point determination.