Study of protonation equilibrium of lorazepam by potentiometry and multiwavelengths spectrophotometry

Author

Department of Chemistry, Faculty of Sciences, Islamic Azad University, Arak Branch, Arak, Iran

Abstract

The acid-base equilibrium of lorazepam was studied by means of potentiometry and
multiwavelengths spectrophotometry. The stoichiometric equilibrium constants were determined
at 25 °C and constant ionic strength 0.1 mol L-1 (NaCl). The acidity constants pK1=1.58±0.05
and pK2=11.67±0.07 were found by potentiometry, and pK1=1.54±0.02 and pK2=11.61±0.03 by
multi-wavelengths spectrophotometry. Potentiometric determination of equilibrium constants
was performed by application of the formation function method. Data analysis program applied
for multi-wavelengths spectrophotometric determination of acidity constants.

Keywords


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