Preparation and in-vitro evaluation of nifedipine loaded albumin microspheres cross-linked by different glutaraldehyde concentrations

Nifedipine-loaded albumin microspheres were prepared by a chemical cross-linking method to develop a sustained release form. The effects of cross-linking agent (glutaraldehyde) on the percentage of drug loading, biodegradability of albumin microspheres and drug release kinetics were investigated in this study. Moreover, the kinetics of nifedipine released from different albumin microspheres were analysed using four different theoretical models, that is, zero order, first order, planar matrix and spherical matrix model. Albumin microspheres prepared with different amounts of glutaraldehyde indicated different release kinetics. Increasing the glutaraldehyde concentration decreased the release rate of nifedipine from albumin microspheres as a result of formation of greater structural strength and more tightly texture. Besides, albumin microspheres gave an adequate fit to either zero order or spherical matrix model, depending on the extent of cross-linking reaction. Copyright (C) 1996 Elsevier Science B.V.