A preliminary study on the morphological and release properties ofhydroxyapatite–alendronate composite materials

Inhibition of osteoclasts by bisphosphonate is one strategy to be explored in order to avoid a revision
surgery. The purpose of this preliminary work is to synthesize hydroxyapatite–alendronate (HA–ALN) composites
as carrier for ALN that could improve its site specific activity. HA–ALN composites were prepared by
the co-precipitation method. Process parameters such as HA:ALN w/w ratio (1:1, 5:1 and 10:1) and HA
incubation times (6, 24, 48 and 72 h) were evaluated. Morphological, physical–chemical characterization
and biocompatibility tests were performed. TEM and SEM analyses confirmed ALN precipitation as fine
network onto HA. The results of physical–chemical characterization confirmed the presence of ALN in the
composites and its interaction with HA. ALN content resulted between 60% and 80% in the HA:ALN 5:1 and
10:1 ratios composites. ALN release reached 80% from HA–ALN 10:1 composites. Biological tests revealed
that complexation with HA increased ALN biocompatibility by three times. These preliminary results demonstrated
that HA–ALN composites could be considered a carrier to control ALN release.