A new polymer-drug conjugate based on poly(N-vinylpyrrolidone-co-maleic anhydride) as support and 2-amino-5-(4-methoxy-phenyl)-1,3,4-oxadiazole, having antimicrobial and antifungal activity, was synthesized by Higashi-Yamazaki reaction. The functionalized copolymer having a substitution degree of 29% was fully characterized in terms of chemical structure by H-1 NMR, FTIR and UV-Vis spectroscopy, and by molecular weight measurements. The crystallization of CaCO3 particles from saturate aqueous solutions in the presence of the newly synthesized conjugate copolymer, comparative with particles prepared in similar conditions but without polymer, has been investigated. The obtained particles were characterized by scanning electron and polarized optical microscopy, X-ray diffraction, particles charge density, and electrophoresis. These new composite materials are excellent candidates for use in biomedical applications, particularly for drug delivery. (C) 2012 Elsevier Ltd. All rights reserved.