Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2023 Feb 25;24(5):4532.
doi: 10.3390/ijms24054532.

Cytotoxic and Bactericidal Effects of Inhalable Ciprofloxacin-Loaded Poly(2-ethyl-2-oxazoline) Nanoparticles with Traces of Zinc Oxide

Mohammad Zaidur Rahman Sabuj  1 , Flavia Huygens  2 , Kirsten M Spann  3 , Abdullah A Tarique  4 , Tim R Dargaville  5 , Geoffrey Will  6 , Md Abdul Wahab  6 , Nazrul Islam  1   3
Affiliations

Cytotoxic and Bactericidal Effects of Inhalable Ciprofloxacin-Loaded Poly(2-ethyl-2-oxazoline) Nanoparticles with Traces of Zinc Oxide

Mohammad Zaidur Rahman Sabuj et al. Int J Mol Sci. .

Abstract

The bactericidal effects of inhalable ciprofloxacin (CIP) loaded-poly(2-ethyl-2-oxazoline) (PEtOx) nanoparticles (NPs) with traces of zinc oxide (ZnO) were investigated against clinical strains of the respiratory pathogens Staphylococcus aureus and Pseudomonas aeruginosa. CIP-loaded PEtOx NPs retained their bactericidal activity within the formulations compared to free CIP drugs against these two pathogens, and bactericidal effects were enhanced with the inclusion of ZnO. PEtOx polymer and ZnO NPs did not show bactericidal activity alone or in combination against these pathogens. The formulations were tested to determine the cytotoxic and proinflammatory effects on airway epithelial cells derived from healthy donors (NHBE), donors with chronic obstructive pulmonary disease (COPD, DHBE), and a cell line derived from adults with cystic fibrosis (CFBE41o-) and macrophages from healthy adult controls (HCs), and those with either COPD or CF. NHBE cells demonstrated maximum cell viability (66%) against CIP-loaded PEtOx NPs with the half maximal inhibitory concentration (IC50) value of 50.7 mg/mL. CIP-loaded PEtOx NPs were more toxic to epithelial cells from donors with respiratory diseases than NHBEs, with respective IC50 values of 0.103 mg/mL for DHBEs and 0.514 mg/mL for CFBE41o- cells. However, high concentrations of CIP-loaded PEtOx NPs were toxic to macrophages, with respective IC50 values of 0.002 mg/mL for HC macrophages and 0.021 mg/mL for CF-like macrophages. PEtOx NPs, ZnO NPs, and ZnO-PEtOx NPs with no drug were not cytotoxic to any cells investigated. The in vitro digestibility of PEtOx and its NPs was investigated in simulated lung fluid (SLF) (pH 7.4). The analysed samples were characterized using Fourier transform infrared spectroscopy (ATR-FTIR), scanning electron microscopy (SEM), and UV-Vis spectroscopy. Digestion of PEtOx NPs commenced one week following incubation and was completely digested after four weeks; however, the original PEtOx was not digested after six weeks of incubation. The outcome of this study revealed that PEtOx polymer could be considered an efficient drug delivery carrier in respiratory linings, and CIP-loaded PEtOx NPs with traces of ZnO could be a promising addition to inhalable treatments against resistant bacteria with reduced toxicity.

Keywords: antibiotic resistance; antimicrobial agents; bactericidal effects; cytotoxicity; digestibility; inhalable formulation; nanoparticles; poly(2-ethyl-2-oxazoline); zinc oxide.

PubMed Disclaimer

Conflict of interest statement

The authors declare no conflict of interest.

Figures

Figure 1
Figure 1
Bactericidal effects of PEtOx, blank NPs, free CIP, and CIP-loaded PEtOx NPs against S. aureus. p > 0.05 (*), p < 0.05 (**).
Figure 2
Figure 2
Bactericidal effects of PEtOx, blank NPs, free CIP, and CIP-loaded PEtOx NPs against P. aeruginosa.
Figure 3
Figure 3
Bactericidal effects of free CIP, ZnO NPs, ZnO-PEtOx NPs, and combination of CIP-ZnO-loaded PEtOx NPs against S. aureus. p > 0.05 (*).
Figure 4
Figure 4
Bactericidal effects of free CIP, ZnO NPs, ZnO-PEtOx NPs, and combination of CIP-ZnO-loaded PEtOx NPs against P. aeruginosa. p > 0.05 (*), p < 0.05 (**).
Figure 5
Figure 5
Effect of CIP alone, blank PEtOx NPs, and CIP-loaded PEtOx NPs on cell viability (%) of (A) NHBE cells, (B) DHBEs, (C) CFBE41o- cell line, (D) HCs macrophages, and (E) CF-like macrophages. p > 0.05 (*), p < 0.05 (**), p < 0.001 (***).
Figure 6
Figure 6
Effect of ZnO NPs, ZnO-PEtOx NPs, and CIP-ZnO-PEtOx NPs on the cell viability (%) of NHBE cells. p < 0.001 (***).
Figure 7
Figure 7
Proinflammatory effects of CIP alone, blank PEtOx NPs, and CIP-loaded PEtOx NPs on (A) NHBE cells, (B) DHBEs, (C) CFBE41o-cell line, (D) HCs macrophages, and (E) CF-like macrophages. The IL-8 secretion levels were normalized with the number of cells by dividing the % cell viability estimated by the LDH assay. Results expressed as the mean ± SD (n = 3) and p > 0.05 (*), p < 0.05 (**), p < 0.001 (***).
Figure 8
Figure 8
FTIR spectra of PEtOx powder and PEtOx NPs before incubating them in SLF.
Figure 9
Figure 9
FTIR spectra of PEtOx powder before and after the incubation period of six weeks in SLF.
Figure 10
Figure 10
FTIR spectra of PEtOx NPs before and after the incubation period of six weeks in SLF.
Figure 11
Figure 11
SEM photomicrographs of PEtOx powder before and after incubating in SLF at different time intervals (A) PEtOx original powder (B) PEtOx 1 week (C) PEtOx 2 weeks (D) PEtOx 3 weeks (E) PEtOx 4 weeks (F) PEtOx 5 weeks (G) PEtOx 6 weeks.
Figure 12
Figure 12
SEM photomicrographs of PEtOx NPs before and after incubating in SLF at different time intervals (A) PEtOx original NPs (B) PEtOx NPs 1 week (C) PEtOx NPs 2 weeks (D) PEtOx NPs 3 weeks (E) PEtOx NPs 4 weeks (F) PEtOx NPs 5 weeks (G) PEtOx NPs 6 weeks.
Figure 13
Figure 13
UV–Vis spectra of PEtOx solution (16 µg/mL) in PBS, PEtOx NPs in PBS (16 µg/mL), and lysozyme solution (0.2 mg/mL) in PBS (pH 7.4) PBS was used as the reference.
Figure 14
Figure 14
UV–Vis spectra of PEtOx powder at different time intervals incubated in SLF. SLF was used as the reference.
Figure 15
Figure 15
UV–Vis spectra of PEtOx NPs at different time intervals incubated in SLF. SLF was used as the reference.
See this image and copyright information in PMC

Similar articles

See all similar articles

Cited by

References

    1. Mahashur A. Management of lower respiratory tract infection in outpatient settings: Focus on clarithromycin. Lung India Off. Organ Indian Chest Soc. 2018;35:143. doi: 10.4103/lungindia.lungindia_262_17. - DOI - PMC - PubMed
    1. Meisner S. Current management of lower respiratory tract infections. Prescriber. 2006;17:48–58. doi: 10.1002/psb.354. - DOI
    1. Newman S.P. Drug delivery to the lungs: Challenges and opportunities. Ther. Deliv. 2017;8:647–661. doi: 10.4155/tde-2017-0037. - DOI - PubMed
    1. Moreno-Sastre M., Pastor M., Salomon C.J., Esquisabel A., Pedraz J.L. Pulmonary drug delivery: A review on nanocarriers for antibacterial chemotherapy. J. Antimicrob. Chemother. 2015;70:2945–2955. doi: 10.1093/jac/dkv192. - DOI - PubMed
    1. Deborah C., John P., Allan P., Paul B., Peter A., Alen W. Ciprofloxacin. A review of its antimicrobial activity, pharmacokinetic properties and therapeutic use. Drugs. 1988;35:373–447. - PubMed

MeSH terms