In this study, ionotropic gelation method was used for the preparation of ibuprofen-loadedcalcium alginate (CALG) and ethylenediamine (EDA) treated calcium alginate (EDA-CALG)microspheres. The effect of EDA-treatment on drug entrapment efficiency, particle size, morphology,swelling behavior and in vitro release characteristics of the microspheres was investigated byvarying its concentration from 0.5 to 2% (v/v). The reduction in drug entrapment efficiency by amaximum of 44.60% was noted for EDA-CALG microspheres compared to untreated CALGmicrospheres. The particle size and swelling index of EDA-CALG microspheres were reducedwith increasing EDA concentration. All the microspheres were observed to retain their sphericalshapes with rough surfaces. EDA-CALG microspheres prepared using 1% and 2% v/v EDA,released almost all of its content within 7 h in pH 6.8 phosphate buffer, however, CALGmicrospheres were found to release the same within 3 h. The intensity of melting endothermic peak ofibuprofen reduced significantly at lower drug load as experienced from DSC thermograms. The FT-IRspectrum of pure ibuprofen, ibuprofen-loaded CALG and EDA-CALG microspheres showed thecharacteristic band of C = O stretching vibration of ibuprofen. Hence, this study revealed thatEDA can be employed for the preparation of ibuprofen-loaded CALG microspheres to retard thedrug release to some extent.