BIODEGRADABLE MAGNESIUM ALLOYS: COMPARISON OF CORROSION RATE IN VITRO AND IN VIVO

Recent years there has been an increased interest in Mg-based alloys as a promising biodegradable implant material. In this connection, comparison of in vitro and in vivo degradation of magnesium alloys has become topical. This article discusses in detail the features of corrosion behavior and compares the corrosion rate of magnesium with different purity and various magnesium alloys in simulated body fluids (SBF) solutions (in vitro) and directly in the body (in vivo). It has been shown that corrosion of biodegradable magnesium alloys in the aqueous environment of the body (in vivo) is not as straight forward as corrosion in various media, simulating a biological fluid (in vitro). Moreover, for Mg alloys, the in vivo corrosion rate is 1–6 times lower compared with in vitro corrosion rate in SBF solutions. It should be noted that pure Mg has the lowest average value of the corrosion rate in vitro. As for alloying, Mg alloys with rare earth elements (Mg-RE) showed the greatest corrosion resistance in vitro and in vivo. At the same time, the average corrosion rate of Mg-RE alloys in vivo is 6 times less than in vitro.