A method of preparing spherical, micro- and macroporous (50 to 550 mu m pores), carbonated apatitic calcium phosphate granules (2 to 4 mm in size) has been developed by using the NaCl porogen technique. A calcium phosphate self-setting cement powder (comprising a specially designed cement powder mixture of alpha-Ca_3(PO_4)_2, CaHPO_4, CaCO_3 and precipitated Ca_(10)(PO_4)_6(OH)_2) was mixed with 65 wt percent NaCl crystals ranging in size from 1 mm down to 400 mu m, followed by kneading with a dilute Na_2HPO_4 initiator solution and then sieving the setting paste to the desired sizes. Embedded NaCl crystals were leached out from the formed granules by soaking in deionized water at room temperature. The calcium phosphate granules comprised macro- and micropores substantially communicating with one another throughout the body with a porosity of 45-50 percent or more. Produced granules were only composed of carbonated, calcium-deficient, poorly-crystallized, apatitic calcium phosphate as the mineral phase, which is quite similar to that of human bones. Granules are used (marketed in Europe under the trade name of "Calcibon~R Granules") as a substitute or a repair material for bone, carrier material for drug delivery and controlled release system. These granules have been the first calcium phosphate granules directly produced from a self-setting calcium phosphate orthopedic cement powder at room temperature, and they are also suitable for augmentation with autologous bone graft, bone marrow aspirate, blood or platelet-rich plasma.
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