Advantages of Cubosomal Formulation for Gatifloxacin Delivery in the Treatment of Bacterial Keratitis: In Vitro and In Vivo Approach Using Clinical Isolate of Methicillin-Resistant Staphylococcus aureus

Abstract

The objective of this study was to enhance the corneal permeation of gatifloxacin (GTX) using cubosomal nanoparticle as a delivery system. Cubosomal nanoparticle loaded with GTX was prepared and subjected for in vitro and in vivo investigations. The prepared GTX-loaded cubosomal particles exhibited nanoparticle size of 197.46 ± 9.40 nm and entrapment efficiency of 52.8% ± 2.93. The results of ex vivo corneal permeation of GTX-loaded cubosomal dispersion show approximately 1.3-fold increase compared to GTX aqueous dispersion. The incorporation of GTX into cubosomal particles resulted in a fourfold reduction in the minimum inhibitory concentration (MIC) value for the GTX cubosomal particles relative to GTX aqueous dispersion. Furthermore, the enhanced corneal penetration of GTX-loaded cubosomal dispersion compared was evident by a significant decrease in the area % of corneal opacity in MRSA infected rats. Moreover, these results were confirmed by photomicrographs of histological structures of corneal tissues from rats treated with GTX-cubosomal dispersion which did not present any change compared to that of the normal rat corneas. In conclusion, treatment of ocular bacterial infections and reduction in the probability of development of new resistant strains of MRSA could be accomplished with GTX-loaded cubosomal nanoparticles.

Keywords: MIC; corneal permeation; cubosomal dispersion; gatifloxacin; keratitis; methicillin resistant Staphylococcus aureus.

Figure 1

TEM photomicrograph of GTX loaded cubosomes.

Figure 2

DSC thermograms of (A) pure GTX, (B) GTX-loaded cubosomal dispersion, (C) blank cubosomal dispersion, (D) P407 and (E) GMO.

Figure 3

Comparison between rabbit corneal permeation of GTX delivered from cubosomal dispersion and aqueous GTX dispersion.

Figure 4

ImageJ-processed photographs of eyes from different groups: group 1 (uninfected untreated rats); group 2 (infected rats without treatment); group 3 (rats treated with GTX aqueous dispersion); and group 4 (rats treated with GTX-loaded cubosomal dispersion). The red color in the processed pictures designates the areas of focal lesions.

Figure 5

The area % of corneal opacity in different groups of rats. ****, group 4 and 3 compared to group 2 (p < 0.0001); #, group 4 compared to group 3 (p < 0.05).

Figure 6

Histological structures of rat corneas stained with H&E of normal rat corneas (group 1), untreated rat corneas infected with MRSA (group 2), rat corneas infected with MRSA and treated with GTX aqueous dispersion (group 3) and rat corneas infected with MRSA and treated with GTX-loaded cubosomal dispersion (group 4).