## 3 Results and Discussion
This extended release profile is advantageous for maintaining therapeutic levels of vancomycin over extended periods, reducing the need for frequent dosing and enhancing the material's suitability for applications in infection prevention and bone regeneration. The data highlight the biphasic nature of drug release, where an initial rapid phase addresses acute therapeutic needs, followed by a sustained release phase that supports prolonged treatment efficacy. This release behaviour is characteristic of bioactive glass systems designed for localized drug delivery, reinforcing their potential in clinical applications. The drug release data were analyzed using kinetic models to describe the release mechanisms; this was performed following previous studies [22; 38]. To assess which model best fits the experimental data, the coefficient of determination (R\({}^{2}\)) was calculated for each model. The results in Figure 8 show an R\({}^{2}\) value of 0.977 for the zero-order model, while the first-order model gave a negative R\({}^{2}\) of 0.978. The Higuchi and Korsmeyer-Peppas models had R\({}^{2}\) values of 0.967 and 0.978, respectively. The Korsmeyer-Peppas model had the highest R\({}^{2}\) value, suggesting that drug release is governed by a combination of diffusion and matrix erosion, which are characteristic of anomalous transport. The Korsmeyer-Peppas model is usually applied to describe drug release from porous materials, where the release mechanism does not follow simple diffusion [39]. An important parameter in this model is the release exponent n, which provides insight into the drug release mechanism. In this study, the calculated n-value was 0.7119, indicating anomalous (non-Fickian) transport [39]. This result implies that drug release is controlled by a combination of diffusion through the matrix and the gradual erosion of the delivery system, aligning with findings from previous research on bioactive glass and polymeric drug delivery systems [40]. Biofilm infections require consistent and high concentration when detected on prosthetics because of their extracellular matrix, which impairs drug penetration. Given that  
Figure 8: The drug release kinetics models show the goodness of fit for the zero-order model, first–order mode, Korsmeyer–Peppas mode, and Higuchi model. the minimum inhibitory concentration (MIC) for _S. aureus_ ranges from 2 to 16 \(\mathrm{\SIUnitSymbolMicro\text{g}}\)/mL [41], biofilm infections require higher concentration and exposure for a longer time, BG-V needs to maintain a much higher concentration for a long period to achieve the complete eradication of biofilms. In this study, BG-V was able to maintain an average of around 229.5 \(\mathrm{\SIUnitSymbolMicro\text{g}}\)/mL daily in vitro which is below the toxic levels identified by [PERSON] et al. (2015), where they found a significant increase in human umbilical vein endothelial cell death from vancomycin concentrations of 2.5 \(\mathrm{mg}\)/mL [42]. By maintaining this level of drug release, BG-V ensures the complete elimination of biofilms while simultaneously dissolving to rebuild bone damaged by the infection. Antimicrobial susceptibility testing was conducted using the agar well diffusion method as shown in Figure 9. Sterilized BG-V samples were placed in wells within the agar to evaluate their antibacterial activity. The experiment was performed in triplicate to ensure the accuracy and reproducibility of the results. The plates were incubated at 37 \(\mathrm{\SIUnitSymbolCelsius}\) for 24 h, after which the zones of inhibition (ZOI) were measured [43]. Figure 9a shows that the disc diffusion test against _S. aureus_ on Mueller-Hinton agar revealed a ZOI of 27 \(\pm\) 0.2 mm, indicating a strong antibacterial effect. Similarly, Figure 9b shows that the test against _E. coli_ showed a ZOI of 35 \(\pm\) 0.4 mm, demonstrating a strong antibacterial effect against this Gram-negative bacterium as well. Figure 9c,d show the negative bioactive glass and positive vancomycin controls, respectively.