Spectrophotometric determination of isoniazid nalidixic acid and flumequine through ternary complex-formation with Cd [II] and rose bengal

ABSTRACT

Simple, sensitive and accurate spectrophotometric procedures for the determination of isoniazid [INH], nalidixic acid [Nx] and flumequine [Fq] are developed. These are based on the reaction of the above mentioned drugs with cadmium [II] to form cationic complexes, which subsequently associate with negatively charged rose bengal to form ion-association ternary complexes. The formed complexes of Nx and Fq are extracted with chloroform, and that of INH with 30% acetone in chloroform to give pink colored solutions with lambda max at 564 nm for Nx and Fq and lambda max at 555 nm for INH. The proposed procedures are applied over concentration ranges of 2.8-5.6 mcg ml-1 of INH, 40-56 mcg ml-1 of Nx and 56-96 mcg ml-1 of Fq. They are successfully applied to the determination of the three drugs in pure and in dosage forms; the relative standard deviations being less than 2%