Endosseous implant

An endosseous implant suitable for application to a human or animal bone, said implant having a surface made from a selected metal or a selected metal alloy or a ceramic, whereby said metal resp. metal alloy is selected from chromium, niobium, tantalum, vanadium, zirconium, aluminium, cobalt, nickel, stainless steels or an alloy thereof, said surface having a smooth or rough texture, wherein said surface has a layer formed thereon of at least one pharmaceutically acceptable organic compound carrying at least one phosphonic acid group or a derivative thereof, which is a pharmaceutically acceptable ester, amide or salt thereof, corresponding to the formula (I):

• A-[P(O)(OH)2]p (I),
• wherein A means A1 or A2, and
• A1 is a residue of a linear, branched or cyclic, saturated or unsaturated, hydrocarbon residue with n carbon atoms, whereby said residue may be substituted by carboxyl and optionally further interrupted by one or more oxygen and/or sulphur and/or nitrogen atoms, carrying p phosphonic acid groups, wherein
• n is a number from 1 to 70, and
• p is 1, 2, 3, 4, 5 or 6, or
• A means A2 and
• A2 is a residue of an amino acid or of a sequence of amino acids respectively of a protein or of a polypeptide;
• or a residue of a specific drug molecule, wherein each residue A2 carries p phosphonic acid groups, and
• p is 1 to 6, when A2 is a residue of an amino acid, of a sequence of amino acids, of a protein or of a polypeptide;
• or
• p is 1, 2, 3, 4, 5 or 6, when A2 is a residue of a specific drug molecule originally not bearing any phosphonic group, optionally falling under the definition given for A1.