Determination of chlorpromazine, thiamine, lincomycin, ofloxacin and theophylline by ternary complex formation with eosin and palladium(II).

Abstract

Color reactions among a drug, an organic dye and a metal ion were studied, and a simple and sensitive spectrophotometric method, without solvent extraction, has been established for the determination of some drugs by ternary complex formation with eosin and palladium (II) (probably involving an ion-association complex between (Pd^II (drug) _n) cation and eosin anion).Beer's law held up to ca. 2.0 × 10^-5 M of each drug at 545 nm in the final volume of 10 ml, with apparent molar absorptivities of 5.7 × 10⁴ 1 mol^-1 cm^-1 for chlorpromazine, 6.7 × 10⁴ for thiamine, 5.5 × 10⁴ for lincomycin, 4.0 × 10⁴ for ofloxacin, and 3.5 × 10⁴ for theophylline. The proposed method was applied to the determination of these drugs in pharmaceutical preparations. A fluorescence quenching method for the determination of these drugs by forming this ternary complex was also investigated for the purpose of enhancing the sensitivity of determination.