¹Department of Chemistry, Faculty of Science and Literature, Suleyman Demirel University, Isparta, Turkey
²Department of Basic Pharmaceutical Sciences, Faculty of Pharmacy, Suleyman Demirel University, Isparta, Turkey
³Department of Medical Services and Techniques, Atayalvaç Vocational School of Health Services, Suleyman Demirel University, Isparta, Turkey DOI : 10.29228/jrp.162 The ionization/protonation (pK_a) constant, which is a physicochemical parameter that directly affects the pharmacokinetic properties of a drug such as absorption, distribution, metabolism, and excretion (ADME), is currently determined by analytical methods. The effect of pH of the mobile phase on the chromatographic behavior of 1-(2- methylbenzonitrile)-3-benzylbenzimidazolium bromide (2) which its synthesis, fully characterization, and antiproliferative activity properties were studied previously, and the protonation constant (pK_a) value were determined in this study. The pKa value of compound 2, benzimidazolium salt, was determined by the reverse-phase liquid chromatographic (RPLC) method at 25 ºC. sspK_a values were evaluated using retention time (t_R) in acetonitrile-water binary mixtures with acetonitrile (ACN) percentages of 40%, 45%, 50% and 55% (v/v). The aqueous pK_a wwpK_a value of the synthesized compound was calculated from the sspK_a value using the macroscopic parameters (dielectric constant and mole fraction) which play an important role in the solvent properties. Obtained wwpK_a values were found to be 11.290 and 11.241, respectively. In addition, the degree of ionization of the related compound was calculated using the wwpK_a values. Keywords : Benzimidazolium salt; hydro-organic mixture; pK_a value; macroscopic parameter