## 3 Results
### Analysis Part
#### 3.2.2 Temporal In Vitro Stability Tests of All DFMACs in Simulated Body Fluids
The PDI values of AMP increased as time went by, due to the aggregation of particles. The average PDI value of CEF was significantly decreased by polymer conjugation. Table 6 indicates that particles of AMP and CEF formed clusters within a day and Table S2 supports that drugs became immobile after the second day. On the other hand, DFMACs showed minimal aggregation at the end of the three-week period and particles exhibited higher mobility values in Table S2. The average particle size of DFMACs was smaller than that of pure drugs. Even after three weeks, all particles of DFMACs remained on the sub-micro scale. Since the stability of drugs increased by polymer conjugation, the formation of clusters was prevented and the size of the particles remained at a sub-micro scale over a three-week period. \begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline
**Time** & **AMP** & **CEF** & **PMVEMA-AMP** & **PIBMA-AMP** & **PEMA-AMP** & **PMVEMA-CEF** & **PIBMA-CEF** & **PEMA-CEF** \\ \hline
0 & 550 & 773 & 345 & 300 & 603 & 542 & 333 & 678 \\
15 & 570 & 783 & 365 & 330 & 620 & 558 & 340 & 621 \\
30 &  
In Table 7, zeta potential values regardless of sign showed a decreasing trend for drugs and DFMACs over time. AMP and CEF became unstable after the first day and the stability of DFMACs extended up to three weeks. Notably, PMVEMA and PEMA conjugated drugs had higher absolute zeta potential values and better stability as also shown in Figure 8.  
An overall decreasing trend in zeta potential can be seen in Figure 8, and DFMACs exhibit higher absolute zeta potential values than drugs. The absolute zeta potential values of drugs drastically decreased after a week, whereas DFMACs exhibited a smoother decline. According to Table 8, all particles were monodispersed and homogenously dispersed in the sample solutions. Similar to basic conditions, conjugation did not significantly affect the PDI values of drugs. All the particles were negatively charged (as shown in Table S3). There was a stronger interaction between particles of the drugs than between the particles of the DFMAC solution in basic PBS solution. The presence of protonated drug molecules in DFMAC solutions reduced the repulsive forces. \begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline
**Time** & **AMP** & **CEF** & **PMVEMA-AMP** & **PIBMA-AMP** & **PEMA-AMP** & **PMVEMA-CEF** & **PIBMA-CEF** & **PEMA-CEF** \\ \hline
0 & \(-30.5\) & \(-7.9\) & \(-28.2\) & \(-27.2\) & \(-24.5\) & \(-19.0\) & \(-18.7\) & \(-23.6\) \\
15 & \(-26. Table 9 indicates that DFMACs exhibited cluster formation at the end of the three weeks, due to the increase in their particle size. However, clusters of particles of AMP and CEF led to some precipitation, causing the particle sizes of the drug solutions to become smaller after 3 days. The chemical composition of the solution affected the particle size of the drugs and DFMACs. In Table 10, the zeta potential values of drug and DFMACs, regardless of sign, showed a decreasing trend over a three-week period. AMP and CEF became unstable after the third day and the second week, respectively. Very low absolute zeta potential values of the drug were being compensated by copolymer conjugation. Absolute zeta potential values of all DFMACs showed stability over the three-week period. In Figure 9, PMVEMA and PEMA conjugated drugs exhibited higher absolute zeta potential values and better stability than drug-functionalized PIBMA copolymers. Free drugs exhibited the lowest absolute zeta potential values. According to Table 11, all particles of DFMACs in sample solutions were monodispersed. Over the three-week period, almost all of the DFMACs exhibited lower PDI values on average compared to antibiotics.