Study of protolytic equilibria of flurazepam

Abstract

Protolytic equilibria of flurazepam, a diprotic base which is sparingly soluble in water, were investigated. The investigations were carried out in the pH range 0–12, at constant ionic strength (0.1 M NaCl) and 25 ± 0.1 °C, by the application of spectrophotometric, pH-metric and solubility methods. The acidity, hydrolysis and equilibrium constants in the heterogeneous system were determined. In addition, a method, based on the application of a formation function to the hydrolytic process, is proposed. Finally, buffer characteristics of flurazepam in the homogeneous and heterogeneous systems were studied.