Xanthene based spectroscopic probe for the analysis of HCV antiviral, daclatasvir dihydrochloride, through feasible complexation reaction

Abstract

Two simple and rapid analytical assay methods were developed and validated utilizing spectroscopic techniques for sensitive and selective estimation of daclatasvir dihydrochloride in pharmaceutical preparations based on anion pair complex formation with eosin Y. The maximum absorbance of the formed complex was achieved at 545 nm in 0.1 M acetate buffer at pH 3.2 and Beer's law for absorbance against daclatasvir dihydrochloride concentration obeyed in the range of 1.0–10.0 μg mL−1 for the spectrophotometric method (method I). The technicality of spectrofluorimetric method (method II) based on measuring the quenching effect of daclatasvir dihydrochloride on the native fluorescence intensity of eosin Y at the same pH and the measurements were accomplished at 543 nm after excitation at 301 nm. The rectilinear calibration graph between daclatasvir dihydrochloride concentration and the fluorescence quenching values (ΔFI) was achieved over the range of 0.1–2.0 μg mL−1. The formation constant for the binary complex was 4.4 × 104 and Gibb's free energy change was −2.7 × 104 J mol−1. Both methods were validated in agreement with ICH guidelines and a successfully applied for the analysis dosage forms with good % recovery. A suggestion for the reaction pathway was supposed.