Investigation of Interaction of Duloxetine with Alginic Acid Polymers

In this study, glutaraldehyde cross-linked alginate bead was prepared and characterized by FT-IR analysis. Its potential to adsorb an antidepressant drug duloxetine hydrochloride (DLU) was investigated. The adsorption studies were carried out in 25mg/L DLU solution in water wherein 0.015-0.035g alginate bead was utilized. The studies were conducted at 25oC under atmospheric pressure with a continuous stirring at 200 rpm. The studies indicated that the polymer had a high affinity to bind to the DLU. The adsorption capacity was found as 5.33 mg of DLU /gram of alginate bead. The DLU binding capacity of the adsorbent was associated to the formation of ion-ion interaction between the quaternized amine moiety present in DLU and the carboxylates available within the alginate structure. Furthermore, the kinetic studies performed indicated that the binding process fitted to the pseudo-second order kinetic model. The rate constant of initial adsorption was found to be 0.0125 g/mg.min. In addition, the results of adsorption equilibrium fitted the Freundlich isotherm. This further pointed out a multilayer coverage and a heterogeneous surface on the bead prepared. Overall, the results indicated that alginate bead utilized appears to be a good natural polymer for efficient removal of highly consumed DLU. Keywords: alginate; antidepressant; duloxetine; removal; water treatment