Investigation of Chloride Anion Binding Properties of Glipizide Drug

This study addresses the anion binding property of Glipizide (GLP), an oral antidiabetic a second-generation drug member of the sulphonylurea (SU) family. GLP effectively interacts with Cl- anion according to 1H-NMR spectroscopic titrations of successive tetrabutylammonium chloride (TBACl) in deuterated chloroform (CDCl3) and dimethyl sulfoxide (d6-DMSO). Upon the addition of TBACl, the change in chemical shift was observed for both N-H protons of SU in CDCl3, whereas it causes a difference in the shift of only one of N-H proton in SU in d6-DMSO. In addition, the data obtained from 1H-NMR spectroscopic titrations was analyzed by DynaFit program to calculate the binding constant (Ka) value between GLP and Cl- anion. It was found that GLP binds Cl- anion in CDCl3 with higher affinity (Ka=77.37 M-1, Fitplot for N-Hh proton at δ=6.47 ppm) than in d6-DMSO (Ka=38.53 M-1, Fitplot for N-Hh proton at δ=6.32 ppm).