## 3 Results and Discussion  
Figure 2 shows the FTIR of the as-synthesized BG-V (red), vancomycin (black), and BG (blue). The vancomycin spectrum shows peaks at 424, 708, 1013, 1058, 1222, 1394, 1490, 1647, 2094, 2959, and 3265 cm\({}^{-1}\) which signify the functional groups of vancomycin, including the amide and hydroxyl stretch around 3265 cm\({}^{-1}\), the C=O stretching vibration from the amide bonds around 1647 cm\({}^{-1}\), and the C-N stretching and bending vibration peaks in the 1200-1500 cm\({}^{-1}\) range [24]. The peaks observed at 2094 and 2959 cm\({}^{-1}\) represent the R-NH-R and -CH\({}_{2}\)-CH\({}_{3}\) functional groups, respectively. The BG spectra peaks include 443, 790, 875, 1043, and 1468 cm\({}^{-1}\), which signify the characteristics of the silica, phosphate, and carbonate peaks. The peaks observed at 790 and 1043 cm\({}^{-1}\) represent the Si-O-Si stretching and bending vibrations that are characteristic of the silicate glass, while the peak observed at 875 represents the P-O bending vibration, and the peak at 1468 represents the carbonate group (CO\({}_{3}\)\({}^{-2}\)) [25]. The BG-V spectra show peaks at 432, 797, 1036, 1341, 1416, 1640, and 3399 cm\({}^{-1}\), which signify the characteristics of the silica, phosphate, and carbonate peaks similar to the BG spectra. Specifically, the peaks at 1036 and 797 cm\({}^{-1}\) represent the Si-O-Si stretching and bending vibrations, characteristic of the silicate glass structures. The broad peak at 3399 cm\({}^{-1}\) suggests hydroxyl stretching with a shift of the peak for the BG-V, indicating interactions between the hydroxyl and amide groups. The higher intensity of the peaks observed at 1341 and 1416 cm\({}^{-1}\) of the BG-V suggests the integration of vancomycin into the BG pores during synthesis. The peak at 1640 cm\({}^{-1}\) suggests retained amide C=O stretching, indicating the maintenance of vancomycin's integrity within the composite. This is consistent with previous studies which demonstrated the successful incorporation of vancomycin into polymeric carriers like PCL microspheres [26] and mesoporous silica  
nanoparticles (MSN) [27]. The spectral evidence provided here agrees with the findings of these studies, confirming the integration of vancomycin without chemical degradation. Figure 3 shows the XRD patterns of vancomycin and BG-V before and after the drug release studies. The black amorphous pattern represents the glass before immersion in PBS for drug release, while the red pattern shows the crystalline phase after immersion in PBS. The blue pattern shows the vancomycin spectrum which has an amorphous structure with a broad band that starts at \(\sim\)10.2\({}^{\circ}\) and ends around \(\sim\)38.8\({}^{\circ}\), which was also observed in other studies [28]. The black pattern shows the amorphous BG-V structure with a broad band that starts at \(\sim\)10\({}^{\circ}\) and ends at \(\sim\)35\({}^{\circ}\) that is characteristic of bioactive glass before immersion in PBS [29]. The integration of vancomycin can be observed through the higher intensity of the BG-V pattern as the two broad peaks overlap as observed in Figure 3b, which compares the XRD pattern of BG without vancomycin and BG-V. Figure 3b shows BG-V, which has a broad amorphous peak with an intensity going up to 1127 a.u., while the BG without vancomycin had the highest intensity at 680 a.u. ; the intensities were measured starting  
Figure 2: FT-IR of vancomycin (black) and BG-V (red) at day 0 and BG (blue). The peaks highlighted represent the functional groups of BG, BG-V, and vancomycin. at the same intensity of 0 a.u., but the figure shows both spectra to clarify the differences between them. Figure 3a also shows the XRD pattern of BG-V after the drug release (red), which revealed distinct crystalline structures formed on the BG after immersion, signifying the formation of hydroxyapatite (HA) and indicating the degradation of the glass as it releases vancomycin.