The effects of ionic strength and temperature on the dissociation constants of adefovir and cidofovir used as antiviral drugs

Abstract

Abstract:The effects of ionic strength and temperature on the dissociation constants of adefovir (PMEA) and cidofovir (HPMPC) used as antiviral drugs were studied at 298 K, 308 K, and 318 K in aqueous media and at different ionic strength backgrounds of NaCl potentiometrically. The dissociation constants of the ligands were determined via the calculation of the titration data with the SUPERQUAD computer program. The thermodynamic parameters ( ∆G , ∆H , and ∆S) for all species were calculated. The dissociation order of nitrogen and oxygen atoms in the ligands according to proton affinities values were obtained using PM6 semiempirical methods. Moreover, p Ka values of the ligands were determined at 0.00, 0.10, 0.15, 0.20, and 0.5 mol dm −3 ionic strength (NaCl) at 298 K. Consequently, when the ionic strength and temperature in the titration cells were increased, the obtained dissociation constants of PMEA (p Ka3 , p Ka4 , and p Ka5) and HPMPC (p Ka2 and p Ka3) decreased.

Synthesis and Determination of Acid Dissociation Constants in Dimethyl Sulfoxide–Water Hydroorganic Solvent of 5,5-Diphenylpyrrolidine N-Aroylthiourea Derivatives

“…Acid dissociation constant is one of resorted data for the studies on molecular modeling and drug design and those determining the optimal conditions of analysis methods (35)(36)(37). Many studies in the literature focused on determining the acidity of the constants of the compounds (29)(30)(31)(32)(33)(34)(35)(36)(37)(38)(39)(40).…”