Application of Cobalt (II)-EDTA Complex as a Reductant for Molybdophosphoric Acid Used for the Spectrophotometric Assay of Aciclovir, Fluconazole, Ramipril and Secnidazole

A new spectrophotometric method has been described for the assay of aciclovir, fluconazole, ramipril and secnidazole based on formation of insoluble molecular complexes with molybdophosphoric acid (MPA) under acidic conditions. As a second step, a colour reaction has been combined to determine MI’A, released from the complex (and the studied drugs in turn), using a chromogenic reductant; cobalt (Ⅱ)-EDTA complex to produce molybdenum blue Mo(subscript 5+). The colour of the produced Mo(subscript 5+) is measured at 700-710 nm. Appropriate conditions were established for the precipitation and the colour reactions to obtain maximum sensitivity. Under the proposed conditions, this method is applicable over concentration range of 40-580μg ML^(-1). The results demonstrated that the proposed method is equally accurate, precise and reproducible as the official or reported methods thus it is recommended for quality control and routine analysis where time, cost effectiveness and high specificity of analytical techniques are of great importance.