Association of vancomycin and calcium phosphate by dynamic compaction: in vitro characterization and microbiological activity

Dynamic compaction has rarely been used to produce drug-delivery devices in granule form. This report considered four processes associating vancomycin and compared dynamic compaction with wet granulation, a classical method. In the wet granulation study, vancomycin was associated with biphasic calcium-phosphate (BCP) granules either by adsorption or incorporation with a new granulation. In the dynamic compaction study, BCP powder was compacted at 1.1, 1.5 and 1.9 MPa. The compacts obtained were crushed and sieved (200–500 μm), and the vancomycin solution was adsorbed on the resulting granules. After crushing and sieving, the compaction of BCP and vancomycin powders produced vancomycin-loaded granules. In each study, 4.76% of vancomycin was associated with BCP. Granules were characterized in terms of porosity, vancomycin release and vancomycin biological activity. Physicochemical studies of BCP and vancomycin showed their structural integrity after dynamic compaction, which prolonged vancomycin release time from 1 to 6 days. However, a microbiological assay indicated that vancomycin had been altered since only 27.7% was found to be active.