Hydroxyapatite dispersions comprising an amino acid as stabilizing agent and method for preparing same

A stable aqueous colloidal dispersion of colloids possessing an apatite structure, exhibiting a pH of between 5 and 10, formed of colloids of oblong shape with a (number-)average length of between 20 and 250 nm and with an equivalent aspect ratio (ratio of the (number-)average length to the equivalent diameter) of between 1 and 300, or of spherical shape exhibiting a diameter of between 10 and 100 nm and comprising one or more amino acids, optionally in the ionized form, as stabilizing agent, wherein said colloids with apatite structure have the formula:

• Ca10−x(HPO4)x(PO4)6−x(J)2−x (I)
• in which:
• x is selected from 0, 1 or 2;
• J is selected from OH−, F−, CO32− or Cl−;
• and in which some phosphate ions (PO43−) or hydrogen-phosphate ions (HPO42−) can be replaced by carbonate ions (CO32−);
• and in which some Ca2+ can be replaced by Mn+ metal cations of alkali metals, alkaline earth metals or lanthanide metals where n represents 1, 2 or 3,
• it being understood that the molar ratio of the Mn+ cation, when it is present, to Ca2+ varies between 0.01:0.99 and 0.25:0.75, and that the substitution of HPO42− ions or of PO43− ions by CO32− ions, the incorporation of CO32− ions as J and the substitution of Ca2+ cations by metal cations is carried out so as to satisfy the electrostatic balance.