Metronidazole Delivery Nanosystem Able To Reduce the Pathogenicity of Bacteria in Colorectal Infection

Metronidazole (MTZ) is a drug potentially used for the treatment of intestinal infections, namely, the ones caused by colorectal surgery. The traditional routes of administration decrease its local effectiveness and present off-site effects. To circumvent such limitations, herein a drug delivery system (DDS) based on MTZ-loaded nanoparticles (NPs) immobilized at the surface of electrospun fibrous meshes is proposed. MTZ at different concentrations (1, 2, 5, and 10 mg mLâ 1) was loaded into chitosanâ sodium tripolyphosphate NPs. The MTZ loaded into NPs at the highest concentration showed a quick release in the first 12 h, followed by a gradual release. This DDS was not toxic to human colonic cells. When tested against different bacterial strains, a significant reduction of Escherichia coli and Staphylococcus aureus was observed, but no effect was found against Enterococcus faecalis. Therefore, this DDS offers high potential to locally prevent the occurrence of infections after colorectal anastomosis.
The authors thank the Portuguese Foundation for Science and Technology (FCT) and CUF, S.A. for the Ph.D. scholarship of A.O. (PD/BDE/142979/2018). Also, the authors thank the FCT for the financial support of L.C.R. (SFRH/BPD/93697/ 2013). This work was also financially supported by the project Bluebiolab − Transboundary Marine Biotechnology Laboratory (0474_BLUEBIOLAB_1_E) financed by the Interreg programme Spain-Portugal through the European Regional Development Fund (ERDF), and by the FCT projects PTDC/CTM-CTM/29813/2017-(POCI-01-0145-FEDER-029813), UIDB/50026/2020, and UIDP/50026/2020