A Novel Drug Delivery System for Bisphosphonates: Innovative Strategy for Local Treatment of Bone Resorption

摘要

One type of potent aminobisphosphonate (Zoledronate) has been chemically associated onto β-tricalcium phosphate [β-TCP] and calcium deficients apatite [CDA]. Two different association modes have been observed, according to the nature of the Calcium Phosphate [CaP] support and/or the initial concentration of the Zoledronate solution. β-TCP appears to promote Zoledronate-containing crystals formation. On the other hand, at concentrations < 0.05 mol.L~(-1) CDA seems to undergo chemisorption of the drug through a surface adsorption process, due to PO_3 for PO_4 exchange, which is well described by Freundlich equations. At concentrations > 0.05 mol.L~(-1), crystalline needles of a Zoledronate complex form onto the CDA surface. The ability of CDA to release Zoledronate, resulting in the inhibition of osteoclastic activity, was shown using a specific in vitro bone resorption model.