Fabrication and dissolution behavior of hollow hydroxyapatite microspheres intended for controlled drug release

Hollow hydroxyapatite (HA) microspheres were fabricated by a simple spray drying method in this study. Moreover, the dissolution behavior of these hollow HA microspheres after immersion in simulated body fluid (SBF) was also studied. The results indicated that the dissolution of the HA microspheres in SBF is not homogeneous in a layer-by-layer fashion but was preferential at different locations of the particle surface. Generically, dissolution preferentially occurs on the location with looser structure and high porosity of the microspheres. The degradable HA microspheres are expected to have potential applications in bone local drug delivery systems.