Measurement of Acefylline Piperazine Interaction and Dissociation Constants in Polymer Solvent Systems

Abstract

In this study the physicochemical interactions of acefylline piperazine drug (APD) were examined in aqueous and aqueous polymer systems viz., aqueous polyethylene glycol (1.0 %w/v) and aqueous polyvinyl pyrrolidone (1.0% w/v). The study was carried within the concentration ranges from 2.0×10-2 to 10.0 ×10-2 mol/dm3 at different temperatures (293.15 to 318.15 K with the difference of 5 K). Various analytical methods such as conductometric, refractometry, and liquid chromatographic (RP-HPLC) were applied. In order to observe the interaction of APD, o  m was calculated to evaluate the structural influence of polymers on the mobility of solute (APD) at different temperatures. α, Kd and Walden product of APD were also assessed in aqueous polyethylene glycol and aqueous polyvinyl pyrrolidone. Solvation was observed by Walden's product showing strong solvation of APD in water-soluble polymer systems. Thermodynamic parameters for APD such as * E , ΔG* , ΔH* and ΔS* have also been evaluated as a function of temperature to determine the exo/endothermic nature of the drug dissociation process. Specific refraction, molar refraction and polarizability of APD in aqueous and aqueous polymer systems were calculated using the Lorentz-Lorentz equation and various interactions were interpreted. Drug's compatibility studies were also performed by HPLC in aqueous and aqueous polymer systems.