## 3 Results and Discussion
### Tga  
Based on the successful incorporation of the drugs, as suggested by the previous characterisation results, the thermal stability of the pristine MOF-5 was compared with the thermal behaviour of the loaded ceph@MOF-5 and met@MOF-5 (Figure 6). The TGA plots of the loaded polymers give information on the weight loss changes with increasing temperatures, due to the presence of antibiotics and composite materials, as displayed in their respective TGA plots below.  
Figure 6: TGA plots of met@MOF-5, Met and pristine MOF-5 (**top**). Ceph, ceph@MOF-5 and pristine MOF-5 (**bottom**) are shown.  
As expected, the TGA plots of the pristine MOF-5 indicated four distinct weight losses [27]: between 52 \({}^{\circ}\)C and 82.5 \({}^{\circ}\)C (5%) due to the removal of water molecules; between 82.5 \({}^{\circ}\)C and 175 \({}^{\circ}\)C (10%) due to the removal of DMF molecules; the third weight loss was assigned to the partial degradation of the MOF-5 framework, between 175 \({}^{\circ}\)C and 412 \({}^{\circ}\)C (12%), while between 412 \({}^{\circ}\)C and 500 \({}^{\circ}\)C (42%) indicated the final weight loss due to the full degradation of the MOF-5 framework at that point [46; 47]. For the met@MOF-5 crystals, the TGA plots showed no weight loss until 150 \({}^{\circ}\)C; the first loss was then between 150 \({}^{\circ}\)C and 178 \({}^{\circ}\)C (13%), and due to the loss of DMF molecules, the second weight loss occurred between 178 \({}^{\circ}\)C and 325 \({}^{\circ}\)C (25%) due to the degradation of the Met drug molecules, which is observed to have its degrading temperature of 180 \({}^{\circ}\)C, within this temperature range. This suggests that the drug was successfully loaded and present in the pores of the MOF-5. The total disintegration of the framework then occurs between 450 \({}^{\circ}\)C and 510 \({}^{\circ}\)C (32%) after which it remains constant until 600 \({}^{\circ}\)C. In the case of ceph@MOF-5 crystals, three major weight losses were observed. The first drop is from 50 \({}^{\circ}\)C to 173 \({}^{\circ}\)C (8%), which can be accounted for by the loss of water and DFM molecules; another major drop is observed between 175 \({}^{\circ}\)C and 327 \({}^{\circ}\)C (52%) due to degradation of the Ceph drug molecules. Compared to the TGA plots of Ceph, they have a similar degrading temperature range suggesting the presence of the Ceph molecules after successful incorporation. Then, another drop in weight from 327 \({}^{\circ}\)C to 500 \({}^{\circ}\)C (15%) was observed due to the breakdown of the MOF framework, and it remained constant until 600 \({}^{\circ}\)C.  
The TGA plots of the polymer composites are also illustrated in Figure 7, from which it was observed that for the PCL-met@MOF-5 and PLGA-met@MOF-5 composites, the polymers began to degrade at approximately 180 \({}^{\circ}\)C, which is noted to be the degrading temperature of Met from Figure 6 and confirms the presence of the loaded MOF in the composites [48].  
In the case of PCL-ceph@MOF-5 and PLGA-ceph@MOF-5, the major degradation began at approximately 300 \({}^{\circ}\)C, which accounts for the degradation of ceph@MOF-5, as depicted in Figure 6 above, and this confirms the successful encapsulation of the loaded MOF into the polymer composites.