title: Determination of pKa values of some antipsychotic drugs by HPLC--correlations with the Kamlet and taft solvatochromic parameters and HPLC analysis in dosage forms.
abstract: In this study, ionization constant (pKa) values were determined by using the dependence of the retention factor on the pH of the mobile phase for four ionizable drugs, namely, risperidone (RI), clozapine (CL), olanzapine (OL), and sertindole (SE). The effect of the mobile phase composition on the pKa was studied by measuring the pKa at different acetonitrile-water mixtures in an HPLC-UV method. To explain the variation of the pKa values obtained over the whole composition range studied, the quasi-lattice quasi-chemical theory of preferential solvation was applied. The pKa values of drugs were correlated with the Kamlet and Taft solvatochromic parameters. Kamlet and Taft's general equation was reduced to two terms by using combined factor analysis and target factor analysis in these mixtures: the independent term and the hydrogen-bond donating ability a. The HPLC-UV method was successfully applied for the determination of RI, OL, and SE in pharmaceutical dosage forms. CL was chosen as an internal standard. Additionally, the repeatability, reproducibility, selectivity, precision, and accuracy of the method in all media were investigated and calculated.
authors.affiliation: Usak University, Department of Chemistry, Faculty of Science and Arts, 64000, Usak, Turkey. senemkamacisanli@gmail.com
authors.forename: Senem
authors.initials: S
authors.lastname: Sanli
authors.forename: Bediha
authors.initials: B
authors.lastname: Akmese
authors.forename: Yuksel
authors.initials: Y
authors.lastname: Altun
mesh_terms: D014150:Antipsychotic Agents / Q000008:administration & dosage / Q000032:analysis*; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D015203:Reproducibility of Results
chemical_list: D014150:Antipsychotic Agents