Spectrofluorimetric study on inclusion interaction of β-cyclodextrin with duloxetine and its analytical application

Fluorescence study on inclusion interaction of duloxetine in beta-cyclodextrin shows significant increase in the fluorescence of duloxetine in the presence of beta-cyclodextiin. The effects of pH and cyclodextrin concentration on the fluorescence spectra are reported. Fluorescence spectroscopy of the host-guest interaction between duloxetine and beta-cyclodextrin shows formation of inclusion complex with a 1:1 stoichiometric ratio. The changes in fluorescence of duloxetine on inclusion in the hydrophobic beta-cyclodextrin cavity is used to calculate its association constants by non-linear regression method. A new spectrofluorometric method is proposed for quantitative determination of duloxetine in dosage forms with limit of detection of 2.0 x 10(-8) mol/L. The linear range is 5.16 x 10(-8) mol/L to 1 x 10(-5) mon and correlation coefficient is 0.9998. The accuracy (recovery 99.5-100.8 %) and precision (RSD 0.58-0.89 %) values of the proposed method are satisfactory.