title: Preparation, characterization and in vitro gentamicin release of porous HA microspheres.
abstract: Hydroxyapatite (HA) microspheres with high porosities were successfully obtained using an improved ice-templated spray drying (ITSD) technique for drug delivery applications. Pore structures and pore sizes of microspheres have great impact on drug loading and release kinetics. Therefore, solvent types, polyvinyl alcohol (PVA) contents and solid loadings of suspensions were adjusted to control the pore structures and pore sizes. Microspheres with interconnected pore networks and aligned pore structures were obtained using camphene-based and tert-butyl alcohol (TBA)-based suspensions, respectively. With the increase of PVA contents in suspensions, the growth of sintering neck became more obvious and the surface of HA particles became smoother. The inner pore structures of microspheres transformed from uniformly distributed cellular pores to three-dimensional interconnected pore networks, with the increase of solid loadings in suspensions. Gentamicin was successfully loaded into porous HA microspheres. The drug loading percentage increased from 40.59 to 49.82% with the increase of porosity of HA microspheres. The release percentage during the initial 18 h increased from 48.72 to 65.68% with the transformation of pore structures from independent cellular pores (main diameter~3 μm) to three-dimensional interconnected pore networks (main diameter>3 μm).
authors.affiliation: State Key Laboratory of Powder Metallurgy, Central South University, Changsha, Hunan 410083, PR China.
authors.forename: Min
authors.initials: M
authors.lastname: Yu
authors.affiliation: State Key Laboratory of Powder Metallurgy, Central South University, Changsha, Hunan 410083, PR China.
authors.forename: Kechao
authors.initials: K
authors.lastname: Zhou
authors.affiliation: State Key Laboratory of Powder Metallurgy, Central South University, Changsha, Hunan 410083, PR China.
authors.forename: Zhiyou
authors.initials: Z
authors.lastname: Li
authors.affiliation: State Key Laboratory of Powder Metallurgy, Central South University, Changsha, Hunan 410083, PR China. Electronic address: dzhang@csu.edu.cn.
authors.forename: Dou
authors.initials: D
authors.lastname: Zhang
mesh_terms: D004337:Drug Carriers / Q000138:chemical synthesis / Q000737:chemistry; D065546:Drug Liberation; D017886:Durapatite / Q000737:chemistry*; D005839:Gentamicins / Q000737:chemistry*; D008855:Microscopy, Electron, Scanning; D008863:Microspheres; D010316:Particle Size; D011142:Polyvinyl Alcohol / Q000737:chemistry; D016062:Porosity; D012997:Solvents / Q000737:chemistry; D013052:Spectrometry, X-Ray Emission; D013500:Surface Tension
chemical_list: D004337:Drug Carriers; D005839:Gentamicins; D012997:Solvents; D011142:Polyvinyl Alcohol; D017886:Durapatite
keywords: Drug release; Hydroxyapatite; Pore structures; Porosities