A preliminary study on the morphological and release properties of hydroxyapatite-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.