Voltammetric and theoretical study of the interaction of ceftriaxone with phenylalanine

Abstract

The interaction between ceftriaxone and phenylalanine (PA) was investigated by cyclic voltammetry and quantum chemical study using DFT (density functional theory) method. The study was carried out in phosphate buffer solution (PBS) at pH 7.0 (which was also used as the supporting electrolyte) by directly dissolving it in twice distilled water. The voltammetric study of ceftriaxone showed well expressed redox peaks at 0.090 V on a GCE in phosphate buffer of pH 7.0 at 50 mVs-1. The cathodic peak currents were linear with different scan rates from 25 to 275 mVs-1 and the correlation coefficient was found to be 0.971 9 and 0.9592 for ceftriaxone and ceftriaxone-PA systems, respectively in the potential range of 0.8-(-0.2) V. The electron transfer rate constant (ks) was calculated for the reduction of ceftriaxone and ceftriaxone-PA interactions as 2.031 and 4.831 s-1, respectively. After the addition of PA to the ceftriaxone solution, the redox binding constant was obtained as K = 1.32×103 M-1 for ceftriaxone-PA interaction, and quantum chemical calculations were performed for ceftriaxone and ceftriaxone-PA complex by the B3LYP method.