Voltammetric analysis of certain 4-quinolones in pharmaceuticals and biological fluids

The voltammetric behaviour of Enrofloxacin (I), Sparfloxacin (II) and Flero xacin (III) was studied using direct current (DCt), differential pulse (DPP ) and alternating current (AC(t)). All the drugs manifest cathodic waves in Britton-Robinson buffer over the pH range of 4.0-11.98. The waves were cha racterized as being irreversible, diffusion-controlled with limited adsorpt ion properties. The diffusion current-concentration relationships were foun d to be rectilinear over the ranges 4 x 10(-5) - 5 x 10(-4) M, 1 x 10(-5) - 2 x 10(-4) M, 1 x 10(-5) - 4 x 10(-4) M using DCt mode for I, II and III, respectively and 1 x 10(-6)-4 x 10(-5) M. 1 x 10(-6)-1 x 10(-4) M. and 2 x 10(-6)-8 x 10(-5) M, using DPP mode For I. II and III respectively, with mi nimum detectability (S/N = 3) of 1 x 10(-7); M for I, II and 2 x 10(-7) M f or III. The proposed method was successfully applied to the determination o f the studied compounds either per se or in formulations and biological flu ids. The results obtained were concordant to those given using reference me thods. (C) 2000 Elsevier Science B.V. All rights reserved.