Ciprofloxacin-Loaded Zein/Hyaluronic Acid Nanoparticles for Ocular Mucosa Delivery

Abstract

Bacterial conjunctivitis is a worldwide problem that, if untreated, can lead to severe complications, such as visual impairment and blindness. Topical administration of ciprofloxacin is one of the most common treatments for this infection; however, topical therapeutic delivery to the eye is quite challenging. To tackle this, nanomedicine presents several advantages compared to conventional ophthalmic dosage forms. Herein, the flash nanoprecipitation technique was applied to produce zein and hyaluronic acid nanoparticles loaded with ciprofloxacin (ZeinCPX_HA NPs). ZeinCPX_HA NPs exhibited a hydrodynamic diameter of <200 nm and polydispersity index of <0.3, suitable for ocular drug delivery. In addition, the freeze-drying of the nanoparticles was achieved by using mannitol as a cryoprotectant, allowing their resuspension in water without modifying the physicochemical properties. Moreover, the biocompatibility of nanoparticles was confirmed by in vitro assays. Furthermore, a high encapsulation efficiency was achieved, and a release profile with an initial burst was followed by a prolonged release of ciprofloxacin up to 24 h. Overall, the obtained results suggest ZeinCPX_HA NPs as an alternative to the common topical dosage forms available on the market to treat conjunctivitis.

Keywords: ciprofloxacin; conjunctivitis; flash nanoprecipitation; hyaluronic acid; nanoparticles; zein.

Figure 1

Evaluation of the physicochemical properties of Zein_HA NPs with and without cryoprotectants. Data are presented as mean ± standard deviation (n > 3), * < p = 0.05, ** < p = 0.01, *** < p = 0.001, **** p < 0.0001.

Figure 2

FTIR spectra of the NPs and raw materials: (A) spectra of the raw materials (zein, HA, CPX, and mannitol) used for the production and lyophilization of the NPs; (B) spectra of the Zein_HA NPs and ZeinCPX_HA NPs.

Figure 3

TGA (A) and DSC (B) analysis of the raw materials (zein, HA and mannitol), Zein_HA NPs and ZeinCPX_HA NPs.

Figure 4

Evaluation of morphological properties of Zein_HA NPs and ZeinCPX_HA NPs: determination of the hydrodynamic diameter values (A), PDI (B), and zeta potential (C). Data are presented as mean ± standard deviation, n = 5, ** < p = 0.01, ****p < 0.0001.

Figure 5

Stability of Zein_HA NPs (A–C) and ZeinCPX_HA NPs (D–F), after lyophilization, for 28 days. Data are presented as mean ± standard deviation, n = 5, ns p > 0.05, * < p = 0.05, ** < p = 0.01, *** p < 0.001, ****< p = 0.0001, values marked with asterisks are statistically different from Day 0 (immediate re-hydration of the NPs upon lyophilization).

Figure 6

Release profile of ZeinCPX_HA NPs in STF at 37 °C, pH = 7.4 for 24 h (non-cumulative). Results are presented as mean ± SEM (n = 3).

Figure 7

Characterization of the biocompatibility of (A) Zein_HA NPs cryoprotected with 5% mannitol and (B) ZeinCPX_HA cryoprotected with 5% mannitol NPs in contact with NHDF cells during 24 h, 48 h and 72 h. Data are presented as mean ± SEM, n = 5, ns—not statistically significant, ** < p = 0.001, **** < p = 0.0001, values marked with asterisks are statistically different from the mean of K⁻.