3.3.3. Antibacterial Activity Assessment

Table 4 shows the collected antibacterial activity data, which revealed the following. The optimum Gr-PV-NE had the largest growth inhibition zone against *S. aureus* (20 ± 1.8 mm) compared with the other tested formulations. The antimicrobial activity of the optimized formulation appeared to be mainly due to its Gr oil content, which is known to have significant antibacterial activity against *S. aureus* due to its components of citronellol, geraniol, linalool, isomenthone, nerol, and citronellyl formate [57]. Such components exert their antimicrobial effects by interacting with the bacterial cell membrane, increasing its fluidity and leading to the leakage of cell components [57]. Such results were further confirmed by comparing the growth inhibition zones for formulations that contained Gr oil with those that contained no Gr oil. Results indicated that the formulations that contained Gr oil enhanced the antimicrobial activity by four times compared with those that did not contain Gr oil. The NE containing Gr oil had 1.6 times the antimicrobial activity as the physical mixture; in the N, the Gr oil present in the nanosized dispersion enhanced the permeation of the formulation across the microbial membrane and potentiated its action. The obtained rsults were found to be significant at asignificance level of 0.05 (*p*-value < 0.05).

### **4. Conclusions**

The present investigation utilized the BBD for the characterization and optimization of a Gr oil–based nanoemulsion loaded with PV for the transdermal management of burn wounds. The fabricated nanoemulsions had a reasonable droplet size of 61 to 138 nm. The experimental design confirmed the substantial synergistic effect of the Gr oil and PV for burn wound healing. Such a blend increased the management of the wound healing and the

anti-inflammatory character and antibacterial effects of each of the constituents. The optimal formulation had up to a 4-fold decrease in the mean burn wound diameter, a 3.81-fold lowering of the IL-6 serum level, a 4-fold increase in the inhibition zone against *S. aureus*, and a 7.6-fold increase in PV permeation upon comparison with different formulations. It was conclusively seen that the obtained nanoemulsions that contained a combination of Gr oil and PV could be considered a promising paradigm for handling burn wounds.

**Author Contributions:** Conceptualization, W.Y.R. and K.M.H.; methodology, S.S.A.M., B.A.E., A.A.F., A.J.A. and A.Y.S.; software, F.Y.S., W.Y.R. and S.S.A.M.; validation, K.M.H., A.J.A.; formal analysis, A.Y.S. and B.A.E.; investigation, F.Y.S.; resources, A.A.F. and W.Y.R.; data curation, A.Y.S.; writing original draft preparation, F.Y.S. and A.A.F.; writing—review and editing, K.M.H.; visualization, W.Y.R.; supervision, W.Y.R., A.J.A. and K.M.H.; project administration, W.Y.R. and S.S.A.M.; funding acquisition, W.Y.R. All authors have read and agreed to the published version of the manuscript.

**Funding:** The Deanship of Scientific Research (DSR) at King Abdulaziz University, Jeddah, Saudi Arabia, funded this project, under grant no. (G-098-166-1442). The authors therefore acknowledge with thanks DSR technical and financial support.

**Institutional Review Board Statement:** Not applicable.

**Informed Consent Statement:** Not applicable.

**Data Availability Statement:** All data available are reported in the article.

**Acknowledgments:** The Deanship of Scientific Research (DSR) at King Abdulaziz University, Jeddah, Saudi Arabia, funded this project, under grant no. (G-098-166-1442). The authors therefore acknowledge with thanks DSR technical and financial support.

**Conflicts of Interest:** The authors declare no conflict of interest.
