Porous calcium deficient hydroxyapatite granules
View Patent ↗The method is for producing porous calcium deficient hydroxyapatite granules and comprises the following steps: (a) subjecting granules of calcium sulfate anhydrous (CSA), calcium sulfate dihydrate (CSD) or calcium sulfate hemihydrate (CSH) to an incubation in an alkaline aqueous solution having a pH-value of less than 10 and containing PO 4 3− ions; whereby the granules of calcium sulfate anhydrous (CSA), calcium sulfate dihydrate (CSD) or calcium sulfate hemihydrate (CSH) comprise interconnected pores with a minimum mean diameter of 3 microns; (b) washing with water the granules obtained after incubation of step a); (c) drying the obtained porous granules of calcium deficient hydroxyapatite; whereby (d) the amount-of PO 4 3− ions present in the incubation of step a) is at least as large as the amount of SO 4 2− ions of the granules used for step (a). The porous calcium deficient hydroxyapatite granules obtained by the invention may be purposefully used as carriers for biologically active substances in particular for proteins.
1. Porous calcium deficient hydroxyapatite granules comprising a plurality of micropores having a minimum mean diameter of 3 microns, wherein the micropores are interconnected by channels having a mean diameter larger than 1 micron and wherein the micropores have a mean diameter of less than 20 microns.
2. The porous calcium deficient hydroxyapatite granules according to claim 1 , wherein the granules have a composition corresponding to Ca (10-x) (PO 4 ) (6-x) (HPO 4 ) x (OH) (2-x) , where 0<x≤2.
3. The porous calcium deficient hydroxyapatite granules according to claim 1 , wherein the granules have a Ca:P ratio in the range of 1.51 to 1.59.
4. The porous calcium deficient hydroxyapatite granules according to claim 1 , wherein a majority of the porous calcium deficient hydroxyapatite granules have a mean diameter of larger than 50 micrometers.