## 3 Results  
### Characterization Part  
#### 3.1.1 Structural Characterization of PMVEMA-AMP DFMAC  
FTIR/ATR and \({}^{1}\)H NMR analysis were used to characterize the synthesized drug-functionalized maleic anhydride copolymers and to provide detailed information and comparison based on chemical structure and functional groups. In Figure 2, comparative FTIR/ATR spectra of PMVEMA, AMP and PMVEMA-AMP are shown.  
According to the FTIR/ATR spectrum of PMVEMA in Figure 2, peaks at \(\
u\) = 1856 cm\({}^{-1}\) (C=O stretching-anhydride), 1771 cm\({}^{-1}\) (C=O stretching-cyclopentanone), 1218 cm\({}^{-1}\) (-O-CH\({}_{3}\) stretching), 1078 cm\({}^{-1}\) (O=C-O-C=O stretching-anhydride) and 920 cm\({}^{-1}\) (-C-H bending) were observed.  
The carbonyl group of the beta-lactam ring in vibration mode appeared around \(\
u\) = 1770 cm\({}^{-1}\)[26] as seen on the FTIR/ATR spectrum of AMP in Figure 2. Carbonyl group absorption for ampicillin trihydrate appeared around \(\
u\) = 1769 cm\({}^{-1}\), and the peak for the side amide link on the beta-lactam ring appeared at \(\
u\) = 1686 cm\({}^{-1}\). A very broad O-H group peak belonging to carboxylic acid was seen around \(\
u\) = 2969 cm\({}^{-1}\).  
According to the FTIR/ATR spectrum of PMVEMA-AMP in Figure 2, broad carboxylic acid at \(\
u\) = 3225 cm\({}^{-1}\) (O-H stretching), alkane at \(\
u\) = 2978 cm\({}^{-1}\) (CH\({}_{3}\) (a)symmetric stretching) and cyclobutane at \(\
u\) = 2939 cm\({}^{-1}\) (CH\({}_{2}\) symmetric stretching) were observed. Peaks at \(\
u\) = 1763 cm\({}^{-1}\) (C=O group of beta-lactam) and 1651 cm\({}^{-1}\), a carboxylic acid peak  
\begin{table}
\begin{tabular}{c c c c c c c c c c c} \hline
**S** & **AMP** & **CEF** & **I** & **I-A** & **I-C** & **II** & **II-A** & **II-C** & **III** & **III-A** & **III-C** \\ \hline pH & 0.12 & 0.003 & 0.3 & 0.012 & 0.003 & 0.003 & 0.3 & 0.003 & 0.12 & 0.006 \\
5\% D & 0.12 & 0.003 & 0.3 & 0.012 & 0.003 & 0.003 & 0.3 & 0.003 & 0.12 & 0.006 \\ PBS & 0.12 & 0.003 & 0.3 & 0.012 & 0.003 & 0.003 & 0.3 & 0.003 & 0.12 & 0.006 \\
0.9\% NaCl & 0.12 & 0.003 & 0.3 & 0.012 & 0.003 & 0.003 & 0.3 & 0.003 & 0.12 & 0.006 \\ \hline \end{tabular}
\end{table}
Table 1: Solution concentrations (mg/mL) of samples for Zeta-sizer and UV/VIS measurements.  
u\) = 1704 cm\({}^{-1}\) (C=O stretching), three substituted alkene peaks at \(\
u\) = 1651 cm\({}^{-1}\) (C=C str.), a 2\({}^{\circ}\) amide (of \(\beta\)-lactam) at \(\
u\) = 1651 cm\({}^{-1}\) (C=O stretching) and a monosubstituted benzene \(\
u\) = 1497 cm\({}^{-1}\) (C-C stretching) peak were also observed.  
In the reaction mechanism, the anhydride was exposed to a ring-opening reaction and anhydride peaks should have disappeared in the FTIR/ATR spectra. The conjugation of drug molecules with polymers led to new amide bond formation which can be observed in the spectra. The characteristic symmetric and asymmetric C=O stretching vibration peaks of anhydride of PMVEMA at 1856 and 1771 cm\({}^{-1}\) disappeared. The carbonyl group peak of the beta-lactam ring of AMP was shifted from 1769 cm\({}^{-1}\) to 1763 cm\({}^{-1}\). After the PMVEMA-AMP conjugation, new peaks at 1763 cm\({}^{-1}\) (-N-C=O) and 1651 cm\({}^{-1}\) (CO-N-H) due to amide formation are seen in Figure 2.  
According to the \({}^{1}\)H NMR spectrum of PMVEMA-AMP in Figure S1a, \({}^{1}\)H NMR (400 MHz, dmso-d6) \(\delta\): 8.31 ppm (1H, N-H), 8.02 ppm (1H, N-H), 7.40-7.31 ppm (5H, C-H), 6.24 ppm (1H, C-H), 6.09 ppm (1H, C-H), 5.85 ppm (1H, C-H), 3.24 ppm (3H, CH\({}_{3}\)), 3.05 ppm (1H, C-H), 2.93 ppm (1H, C-H), 2.34 ppm (1H, C-H), 1.98 ppm (1H, C-H), 1.92 ppm (6H, CH\({}_{3}\)), 1.23 ppm (2H, CH\({}_{2}\)).