Abstract
A simple, selective and highly sensitive spectrofluorimetric method for the quantitative detection of an antiviral drug, daclatasvir (DCV) has been developed and analytically validated in its pure form, in its commercially available pharmaceutical preparations, and in hepatitis-C (HCV) patient’s plasma. The method was based on recording the native fluorescence of DCV that exhibit an emission wavelength maximum at 380 nm upon excitation at 320 nm. Many factors affecting the fluorescence intensity and the method sensitivity including pH, type of surfactant and solvent have been studied and optimized. In addition, a stability-indicating study was performed in accordance with the guidelines of the International Conference on Harmonization (ICH), to detect the drug in the presence of its degradation products which validates the method for application in quality control laboratories. In addition, extraction of DCV from the plasma proteins was performed using a simple technique that was based on using methanol and borate buffer (pH 9) that gave a recovery of ~95%. The results showed that DCV could be detected using this method in the pure form (with a linear range of 2-1000 ng/mL), commercially available tablets and in plasma samples (with a linear range of 5-1000 ng/mL), without any interferences. Furthermore, the method was also analytically and clinically validated according to the Food and Drug Administration (FDA) guidelines, with limit of detection (LOD) of 0.3 and 0.5 ng/mL for DCV in the pure form and plasma samples, respectively.