Peculiarities of influence of anionic modification on formation of Na+, Mg2+, Zn2+-containing calcium phosphates

The paper presents a study of the effect of adding carbonate or borate anions to the initial solution of the Ca2+-Mg2+-Zn2+-Na+-PO43- system on the formation of calcium phosphates containing Na+, Mg2+, Zn2+. In the & Scy;a2+-Mg2+-Zn2+-Na+- PO43- system, the biphasic calcium phosphates (mixture of phases based on & Scy;& acy;10(& Rcy;& Ocy;4)6(& Ocy;& Ncy;)2 and 6-& Scy;& acy;3(& Rcy;& Ocy;4)2) have been obtained. It was established that an increase in the amount of Zn2+ in the initial solution leads to an increase in the content of phase 6-& Scy;& acy;3(& Rcy;& Ocy;4)2 from 25wt% to 75wt% in biphasic calcium phosphates and its particles size from 35 to 71 nm. In vitro tests of the modified calcium phosphates with different anionic composition in model solution at 37 degrees C showed the highest activity: an increase in pH more than 35% after first 48 hours and for 14 days of the study for calcium carbonate apatite phosphate containing Na+ (0,5wt%), Mg2+ (0.5wt%) and Zn2+ (1.7wt%). At the same time, boratecontaining phosphate with a similar content of trace elements showed activity only during first 48 hours with a pH change of 20%. Obtained results showed the possibility of obtaining apatiterelated modified calcium phosphate with different dissolution rates by changing the nature of anionic dopant when designing materials for orthopedics.