Composite brushite-monetite-newberyite cements loaded with vancomycin and their efficiency against infections of: In vitro and in vivo research

Composite cements containing brushite, monetite and newberyite as dominating phases were created and used as drug (vancomycin) carriers. Brushite-monetite-newberyite cement with variable composition was obtained by replacing Ca2+ ions with Mg2+ in the initial cement component. Starting powder mixtures for cement preparation synthesized via solid state reaction consisted of MgxCa(3-х)(PO4)2 (x = 0, 0.75, 1.5, 2.25, 3), monocalcium phosphate monohydrate Ca(H2PO4)2·H2O with and without vancomycin as antibacterial agent. 100 mg of powder of a pharmaceutical substance per 1 g of the dry cement powder was added before cement sample preparation. Mixing liquids used were water solutions containing sodium pyrophosphate hexahydrate Na4P2O7·10H2O and citric acid monohydrate C6H8O7·H2O as set-retarding additives. An increase in the concentration of Mg2+ ions entail an increase in pH during preparation and a decrease in porosity of cement sample. Incorporation of vancomycin at the stage of preparation of the cement mixture does not affect the strength characteristics, porosity and pH of the cement stone. The prolongation of the release of vancomycin depends on the composition and characteristics of the cement stone. The activity of vancomycin against Staphylloccoscus aureus and Escherichia coli the process of hydration of cement and its dissolution was confirmed by appropriate tests in vitro. In vivo studies confirm the biocompatibility, resorbability of cements, and the effectiveness of their use as carriers of vancomycin in the treatment of purulent-septic inflammation.