Spectrophotometric determination of sparfloxacin in pharmaceutical preparations by ternary complex formation with Pd(II) and eosin

A simple, sensitive, and direct spectrophotometric method has been developed for the assay of sparfloxacin in bulk and pharmaceutical preparations. The proposed method is based on the formation of ternary complex between an investigated drug, palladium(II) ion and eosin in the presence of methylcellulose as surfactant and acetate buffer of pH 4.2. Spectrophotometrically, under the optimum conditions, the ternary complex showed absorption maximum at 550 nm, with apparent molar absorptivity of 2.69 x 10(4) l mol 21 cm 21, Sandell's sensitivity of 0.01458 mu g ml 21 and linearity in the concentration range 1.6-16 mu g ml(-1). The composition of the ternary complex was studied by Job's method of continuous variation and the result indicated that the molar ratio of SPFX: Pd: eosin is 1: 1: 1. The optimum reaction conditions and other analytical parameters are evaluated. The proposed method was successfully applied for the determination of SPFX in its pharmaceutical product with mean percentage recoveries of 99.71\%. The observed data has been subjected to statistical analysis, which revealed high accuracy and precision.