Synergistic effect of cerium and structure directing agent on drug release behavior and kinetics

This work was mainly aimed at the study of the dual effect of cerium and structure directing agent template concentration, on vancomycin release profiles and kinetics from Ce-substituted mesoporous bioactive glasses (MBGs). MBG based on (20-x) B2O3 - 55 SiO2 - 20 CaO - 5 P2O5 - x Ce2O (x = 0, 1 and 3 mol %) was synthesized by the evaporation-induced self-assembly process using two molar ratios (0.01 and 0.02 molar ratio) of nonionic block copolymer Pluronic (R) 123 (P123) surfactant. The TGA-DTA, FTIR, and textural features analyses were carried out for the glasses. Moreover, the in vitro bone-forming activity and degradation analysis were tested using simulated body fluid (SBF). The drug loading capacity, drug release profile, and kinetics (using different kinetic models such as first order, Higuchi, Hixson-Crowell, and Baker-Lonsdale models) were determined using vancomycin as a drug model. The results showed that the isotherms of all MBGs fit with type IV isotherms, and the surface area of MBGs synthesized by 0.02 M template was higher than that prepared by 0.01 M, where it ranged from 174.05 m(2).g(-1) to 256.73 m(2).g(-1). The pore size diameter was decreased as cerium content increased in all MBGs (decreased from 5.44 to 3.54 nm). Moreover, the MBGs induced the formation of a bone-like apatite layer, and their biodegradation properties can be tailored by controlling glass composition. Furthermore, Ce-free MBGs showed the lowest drug adsorption and the highest drug release percentage. The drug release kinetic was best fitted with Higuchi and Baker-Lonsdale models which denoted that the mechanism of drug release from MBGs was a diffusion release from spherical particles. In conclusion, vancomycin release was controlled by the glass composition. Meanwhile, the MBGs synthesized in this study are proposed to be applied for bone regeneration, bone cancer treatment, and reducing the bacterial activity around the tumor site. [GRAPHICS] .