Spectrophotometric Determination of Quinolone Antibiotics by an Association Complex Formation with Aluminum(III) and Erythrosin

A simple and sensitive spectrophotometric method for the determination of quinolone antibiotics was established based on an association complex formation with aluminum(III) and erythrosin. In the determination of ofloxacin as a quinolone antibiotic, Beer's law is obeyed in the range of 0.1 - 3.2 µg ml-1, with an effective molar absorptivity at 555 nm and the relative standard deviation being 1.2 × 105 L mol-1 cm-1 and 0.9% (n = 6). This method was successfully applied to the assay of quinolone antibiotics in pharmaceutical preparations.