2010

Zinc-Doped Tricalcium Phosphate Ceramic for Surgical Implants

This material exhibits an osteogenesis-promoting effect without toxicity, making it suitable as a surgical implant.

A ceramic body consisting of the phases of tricalcium phosphate and/or hydroxyapatite provides biocompatibility with hard tissues. When such a ceramic body is implanted in a bone, direct connection is formed between the bone and the ceramic body without intervention of any fibrous connective tissues. This zinc-containing or zinc-doped ceramic material mainly consists of tricalcium phosphate and is suitable as a ceramic material for biomedical use. In particular, the material provides surgical implant materials for hard tissue consisting of zinc-doped tricalcium phosphate to promote bone formation by releasing zinc in the body.

Several ceramic materials are approved for use as surgical implants for hard tissue in the body, including alumina, hydroxyapatite, tricalcium phosphate, AW-glass ceramic, and carbon. A ceramic material for a surgical implant has no pharmaceutical effect to promote bone formation, to inhibit bone resorption, or to promote tissue restoration. Therefore, it is necessary for a patient to be administered with some supplemental medicines, in addition to the surgical implants, in order to promote bone formation. Zinc is known to have these pharmaceutical effects when taken into the body in a limited dose.

The material provides a ceramic body consisting of tricalcium phosphate doped with zinc in an amount in the range from 0.0126 to 1.26% by weight calculated as zinc based on the weight of the ceramic material.

The material, in the form of a powder, can be prepared by solid-phase reaction methods, liquid-phase reaction methods, and mechanochemical reaction methods from the starting materials, including zinc compounds or zinc ions, calcium compounds or calcium ions, and phosphate compounds or phosphate ions. Among these known methods, the liquid-phase reaction method is preferred. In the liquid-phase reaction method, solutions capable of forming tricalcium phosphate by blending are mixed with a soluble zinc compound in a calculated amount to give a desired content of the zinc dopant. The solutions are mixed together to effect co-precipitation of zinc with tricalcium phosphate. The precipitates are collected by filtration, followed by drying and calcination. The ceramic powder is blended with a binder and shaped into a green body, which is subjected to sintering at a high temperature to give a sintered body.

By virtue of the limited content of zinc and the form of solid solution in which zinc is contained, the material exhibits an osteogenesis-promoting effect without toxicity, which is suitable as a surgical implant.

This technology is offered by the Japan Industrial Technology Association. For more information, view the yet2.com TechPak at http://info.hotims.com/28053-164.