# Rifampicin-Loaded PLGA/Alginate-Grafted pNVCL-Based Nanoparticles for Wound Healing
## 4 Conclusions  
In the specialized literature, there are not enough formulations that can be used as postoperative wound sealants. Starting from this fact, the authors of this study considered that it is useful to develop a nanoparticulate formulation based on alginate grafted with poly(N-vinylcaprolactam) and coated with PLGA loaded with rifampicin (RF). Rifampicin (RF) is an antimicrobial drug which manages and treats diverse mycobacterial infections and gram-positive bacterial infections present at wounds after surgeries. However, the topical therapy with rifampicin-based formulations seemed to be efficient not only for treating infections but also to contribute to the healing process. The newly synthesized nanoparticles based on grafted alginate and poly(N-vinylcaprolactam) and PLGA (AgA-g-PNVCL/PLGA) contribute to the healing process of a wound. The methods used were at first the synthesis of the copolymer of alginate and pNVCL via grafting from technique and radical polymerization followed by W/O/W emulsification by use as an oil phase PLGA dissolved in dichloromethane (DCM). The formed nanoparticles were characterized by means of their particle size showing a size of 200 nm for those particles loaded with RF; FT-IR spectroscopy proved the chemical identity of the copolymer and the conjugate. The presence of bands of each pure substance within the new product together with the broadening of OH- and COOH-showing interactions led to the substance identification. Morphological observation performed via SEM revealed the presence of the RF particles within the polymeric network; the thermal characteristics determined via DSC indicated the presence of a form II RF which is less susceptible to dissolution, explaining its low drug loading and in vitro release profile. It seemed that due to the low solubility of the drug together with the susceptibility to be strongly attached to the polymeric matrix via H bonds, a low released amount of RF was determined as approximatively 10% within 4 h from the administration. However, the analysis of the kinetics of the release profile showed that the delivery process was based more on a non-Fickian mechanism up to the erosion of the polymeric matrix. The cytotoxicity of the tested formulations via MMT assay (pure RF, unloaded nanoparticles, and RF-loaded nanoparticles) revealed the non-toxic character of the formulations, and the inhibitory concentrations (IC50) were determined as 192.1 ug/mL for the nanoparticles, 208.8 ug/mL for pure rifampicin, and 718.1 ug/mL for the nanoparticles loaded with rifampicin. Wound closure capacity was assessed via in vitro scratch assay and a total of 60% closure for the prepared RF-loaded nanoparticles  
Figure 10: Wound healing as a percentage of 3T3-L1 cells incubated with control (DMEM + 1%FBS), rifampicin, nanoparticles, rifampicin + nanoparticles for 30 h. \(p\) < 0.05 \({}^{\star}\), \(p\) < 0.01 \({}^{\star\star}\), indicated statistically significant difference between groups. was found. Considering the double role rifampicin was used for, the result was considered satisfactory in the way that these formulations could be used more with the wound irrigation postsurgery to avoid infections and to contribute to the healing. The main limitation of the study consisted of not having enough case studies regarding the usage of rifampicin entrapped within polymeric nanoparticles to compare the results and to make a fair opinion. However, the obtained in vitro results for the delivery capacity and the wound healing ability will be studied further in an in vivo environment. Conceptualization, T.B., C.M.G., C.N.Y., D.V.T. and R.D. ; validation, N.B. and L.A.; investigation, T.B., C.N.Y. and A.-D.P. ; resources, T.B. and N.B. ; writing--original draft preparation, T.B. and C.N.Y. ; writing--review and editing, D.V.T., A.-D.P. and C.N.Y. All authors have read and agreed to the published version of the manuscript. This research received no external funding. Not applicable.