There are several testing methods. Researchers conduct in vitro degradation studies under controlled laboratory conditions to simulate the physiological environment. Samples are immersed in buffered aqueous solutions at physiological temperature and pH value. According to ASTM G31-72 [14] , the degradation process is monitored over time through measurements of mass loss, changes in mechanical properties, and analysis of degradation byproducts. Electrochemical measurements use techniques such as potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) to evaluate corrosion behavior. Table 1 shows the degradation rate of some magnesium alloys in simulated body fluid (SBF). Surface analyses use scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), and X-ray diffraction (XRD) to analyze surface morphology and composition changes over time. Spectroscopic techniques such as Fourier-transform infrared spectroscopy (FTIR) or nuclear magnetic resonance (NMR) spectroscopy can be used to analyze chemical changes.

In addition to in vitro studies, in vivo degradation studies involve implanting biodegradable magnesium alloy in animal models or human subjects. Degradation rates obtained via in vitro experiments are not necessarily the same as in the in vivo case, however, experiments in vivo will help define what the degradation rate should be. In vivo studies provide insights into how degradation occurs within a biological environment and how it may affect tissue response and long-term outcomes. ASTM F 763-04 [18] can be referenced in vivo test. Imaging techniques, such as X-rays, micro-computed tomography (micro-CT), or MRI to monitor the degradation process and structural integrity over time. Histological analysis is conducted to examine tissue samples around the implantation site to assess biocompatibility and inflammatory response.

A useful degradation model should account for the underlying biological environment. Empirical models can be developed based on experimental data to predict degradation rates under various conditions. For kinetic models, kinetic equations are used to describe the rate of magnesium dissolution and formation of corrosion products. Finite Element analysis (FEA) can simulate the degradation process to predict how the alloy will degrade over time in different environments.

High-quality data are the precondition for analyzing. Data are first collected from experimental studies, including composition, processing parameters, and degradation rates. Key features influencing degradation are identified, such as alloy composition, microstructure, and environmental factors. Then machine learning algorithms e.g., regression models, are used to develop predictive models of degradation rates. The models should be validated with independent datasets to ensure accuracy and generalization.

Alloying with different elements shows various degradation rates for Mg alloys in biomedical applications [20] . Alloying elements like calcium, zinc, and rare earth elements can influence the degradation rate and mechanical properties. Trace impurities can significantly affect degradation behavior.

Fine-grained structures generally exhibit different degradation rates compared to coarse-grained ones. The degradation of a porous magnesian sample in the biological environment is remarkable as porosity on the sample increases the total surface area and increases the risks of metal ion leaching [21] . In addition, the surface oxides’ possible chemical reactions with the physiological fluids significantly influence the applicability of the porous structure. Secondary phases Mg alloys [22] and intermetallic compounds can act as galvanic cells, affecting degradation.

Biodegradable coatings or surface modifications can be applied to control degradation rates. Some studies developed coatings and surface treatments to regulate the degradation rate [23] [24] . Anodized layers can provide initial protection but must degrade synchronously with the underlying alloy. Figure 1 [25] schematically illustrated the coating methods potentially suitable for Mg alloys.

Varying pH levels and ion concentrations in the physiological environment can accelerate or decelerate degradation rate. Cyclic loading and mechanical stress can influence degradation rate through mechanisms like stress corrosion cracking and fatigue. Inorganic ions and cyclic loading may accelerate the degradation rate of magnesium alloys. While organic substances could decrease the degradation rate of Mg alloys [26] .

Cytotoxicity tests are useful steps to determine the potential toxicity of a test substance. Cytotoxicity assays can be developed according to ISO 10993-5 [27] to assess the toxicity of biomedical Mg-alloys degradation products on cell cultures.

Referring to ISO 10993-6 [28] , histological analysis can examine tissue responses to implanted materials, including inflammation and fibrosis. And it is used to monitor the degradation products in vivo that dissolved into the surrounding tissue.

Clinical translation should ensure compliance with regulatory standards for biomedical implants. The degradation behavior of magnesium alloys should be continuously monitored over extended periods to capture any unexpected phenomena or late-stage degradation mechanisms. Artefact production may be used as an alternative approach for degradation tracking to determine the degradation rates of Mg alloys implants [3] . Long-term in vivo studies can be conducted to assess the performance and safety of the magnesium alloys over the intended lifespan of the medical implants.