Mixture designs to assess composition-structure-property relationships in SiO₂-CaO-ZnO-La₂O₃-TiO₂-MgO-SrO- Na₂O glasses: Potential materials for embolization

Embolization with micron-sized particulates is widely applied to treat uterine fibroids. The objective of this work was to develop mixture designs to predict materials composition-structure-property relationships for the SiO2-CaO-ZnO-La2O3-TiO2-MgO-SrO-Na2O glass system and compare its fundamental materials properties (density and cytocompatibility), against a state-of-the-art embolic agent (contour polyvinyl alcohol) to assess the potential of these materials for embolization therapies. The glass structures were evaluated using 29Si MAS NMR to identify chemical shift and line width; the particulate densities were determined using helium pycnometry and the cell viabilities were assessed via MTT assay. 29Si MAS NMR results indicated peak maxima for each glass in the range of -82.3 ppm to -89.9 ppm; associated with Q2 to Q3 units in silicate glasses. All experimental embolic compositions showed enhanced in vitro compatibility in comparison to Contour PVA with the exceptions of ORP9 and ORP11 (containing no TiO2). In this study, optimal compositions for cell viability were obtained for the following compositional ranges: 0.095-0.188 mole fraction ZnO; 0.068-0.159 mole fraction La2O3; 0.545-0.562 mole fraction SiO2 and 0.042-0.050 mole fraction TiO2. To ensure ease of producibility in obtaining good melts, a maximum loading of 0.068 mole fraction La2O3 is required. This is confirmed by the desirability approach, for which the only experimental composition (ORP5) of the materials evaluated was presented as an optimum composition; combining high cell viability with ease of production (0.188 mole fraction ZnO; 0.068 mole fraction La2O3; 0.562 mole fraction SiO2 and 0.042 mole fraction TiO2).