Spectral study on nuclear fast red-clomifene citrate-sodium dodecyl benzene sulfonate system and its analytical application

The interaction of clomifene citrate with nuclear fast red and sodium dodecyl benzene sulfonate (SDBS) was investigated by absorption and resonance rayleigh scattering (RRS) spectrometry. Clomifene citrate can react with nuclear fast red and sodium dodecyl benzene sulfonate to from a ternary complex, resulting in the enhancement of RRS intensity and the appearance of new RRS peaks. Based on that, a novel method is proposed for the determination of clomifene citrate by RRS technique. On the optimum conditions, there was good linearship between the increments of RRS intensity and the concentration of clomifene citrate in the range of 0.25 to 20.0 μg/mL, with the detection limit of 29 ng/mL. The proposed method was applied to assay the clomifene citrate tablets and capsules in agreement with the method in Chinese Pharmacopeia. In addition, the method was also applied to detect clomifene citrate in serum and urine samples with satisfactory results. The studies indicate that clomifene citrate acts as a bridge to band with nuclear fast red and SDBS by virtue of electrostatic attraction to form ion-association complexes.