Abstract: A medical instrument in which an inorganic salt solid such as apatite into which a peptide hormone or the like is embedded is placed so that a metal or the like is coated therewith, in which the inorganic salt solid is provided by controlled delay co-precipitation or the like in an unstable supersaturated calcium phosphate solution, and the medical instrument is exposed to ionizing radiation at a dose sufficient for sterilization.

Abstract: The present invention provides porous material of calcium phosphate of high strength whose open pores penetrate the porous body and have a size of 70 ?m or more, preferably 100 ?m or more, and are arranged in a three-dimensional network, whose porosity is sufficiently high for blood vessels to invade and perforate itself or for cells to infiltrate itself, whose chemical composition, in particular, Ca/P molar ratio can be freely changed within the range of 0.75 to 2.1, to which elements important for facilitating osteogenesis and producing resorbable effect can be added, and whose phase composition can be relatively easily changed. The invention is porous sintered compact of calcium phosphate which has artificially formed, penetrated open pores 70 ?m to 4 mm in diameter, whose porosity is from 20% to 80%, and whose chief ingredient is calcium phosphate having a Ca/P molar ratio of from 0.75 to 2.1.