A Contribution to the Glimepiride Dissociation Constant Determination

Abstract

Knowledge of druglike properties, such as dissociation constants (pK(a)), is of great importance in drug development and analysis. However, poor aqueous Solubility often Causes serious limitations ill accurate determination of a drug's pK(a). In this Study, the apparent dissociation constant (pK(a)') of the poorly soluble drug, glimepiride, has been determined by application of the spectrophotometric and Solubility methods. Compared to the literature reported glimepiride pK(a)' values of 4.99 +/- 0.50 and 6.2 +/- 0.1, the values obtained in the present study were 8.07 +/- 0.02 and 7.26 +/- 0.01 determined by the spectrophotometric and Solubility method, respectively. In addition, the advantages of these two methods in pK(a)' determination of glimepiride are discussed.