Synthesis of ethylenediamine linked β-cyclodextrin dimer and its analytical application for tranilast determination by spectrofluorimetry

A synthesis of β-cyclodextrin (β-CD) dimer, containing two β-CD moieties that are linked through their sides by ethylenediamine, was presented. The dimer was characterized by means of IR, 1H NMR, 13C NMR, and elemental analysis. The inclusion complexation behavior of β-cyclodextrin dimer with tranilast was studied in an aqueous KH2PO4–citric acid buffer solution of pH 2.00 at room temperature by spectrofluorimetry. Based on the significant enhancement of fluorescence intensity of tranilast, a spectrofluorimetric method with high sensitivity and selectivity was developed for the determination of tranilast in bulk aqueous solution in the presence of ethylenediamine β-CD dimer. The apparent association constant of the complex was 8.39 × 103 L mol−1, and the linear range was 10.8–1.40 × 104 ng mL−1 with the detection limit 3.2 ng mL−1. There was no interference from the excipients normally used in tablets and serum constituents. The proposed method was successfully applied to the determination of tranilast in serum.

Tranilast can give off fluorescence in organic solvent, but it showed a yield in the aqueous solution. When ethylenediamine linked β-CD dimer was added to the aqueous solution of tranilast, ethylenediamine linked β-CD dimer reacted with tranilast to form an inclusion complex, we can observe an obvious increase in fluorescence intensity of tranilast. However, the fluorescence intensity did not obviously enhance when β-CD was added to the aqueous solution of tranilast. So the spectrofluorimetric study of the interaction between ethylenediamine linked β-CD dimer and tranilast was carried out.Figure optionsDownload as PowerPoint slide