J. Technology and Education, Vol.16, No.2, pp.69-76, 2009

研究論文

　

　

Preparation of hydroxyapatite/calcium alginate composite gel

and its release characteristics by pH

　

Sachiko OBARA¹, Takeshi YAMAUCHI*^{1, 2} and Norio TSUBOKAWA^{1, 2}

　

¹Graduate School of Science and Technology, Niigata University;

²Center for Transdisciplinary Research, Niigata University

8050, Ikarashi 2-nocho, Nishi-ku, Niigata, 950-2181, Japan

*yamauchi@gs.niigata-u.ac.jp

　

(Received December 2, 2009; Accepted December 16, 2009)

　

ABSTRACT

Bone filling materials made from hydroxyapatite are used for treating bone defects caused by disease or injury. This material promotes the reproduction of new bone by injection into bone cavities. Even though hydroxyapatite has been utilized as a bone-filling material, it requires a long time to be replaced with host bone after implantation. Composite materials composed of hydroxyapatite and hydro-gels would be suitable to fill large bone defects and would be easily absorbed by the patient’s body. Furthermore these materials could be used for drug carrier by stimulus response.

　In this study, a hydroxyapatite/calcium alginate composite gel containing VB₁₂ was synthesized in one step and the release characteristics of hydroxyapatite/calcium alginate composite gels were evaluated. The amount of VB₁₂ released from the gels was maximum at pH 5 and the release of VB₁₂ was inhibited at other than pH 5. The amount of VB₁₂ released from the composite gel increased with the content of hydroxyapatite because hydroxyapatite made the pore size of the composite gel larger. Therefore the release characteristics of the composite gel could be controlled by pH and the content of hydroxyapatite. It is estimated that the composite gels containing drugs are expected to be applied to bone filling materials which have the function of drug carrier.

　

Key words: Hydroxyapatite, Calcium alginate, Composite gel, Release characteristics