A Comparison of Azithromycin and Tobramycin Eye Drops on Epithelial Wound Healing and Tolerance After Penetrating Keratoplasty

Liposomal dexamethasone-moxifloxacin nanoparticle combinations with collagen/gelatin/alginate hydrogel for corneal infection treatment and wound healing

Infectious keratitis is still one of the major causes of visual impairment and blindness, often affecting developing countries. Eye-drop therapy to reduce disease progression is the first line of treatment for infectious keratitis. The current limitations in controlling ophthalmic infections include rapid precorneal drug loss and the inability to provide long-term extraocular drug delivery. The aim of the present study was to develop a novel ophthalmic formulation to treat corneal infection. The formulation was prepared by constructing moxifloxacin (MFX) and dexamethasone (DEX)-loaded nanostructured lipid carriers (Lipo-MFX/DEX) mixed with a collagen/gelatin/alginate (CGA) biodegradable material (CGA-Lipo-MFX/DEX) for prolonged ocular application. The characteristics of the prepared Lipo-MFX/DEX nanoparticles were as follows: average size, 132.1 ± 73.58 nm; zeta potential, -6.27 ± 4.95 mV; entrapment efficiency, 91.5 ± 3.5%; drug content, 18.1 ± 1.7%. Our results indicated that CGA-Lipo-MFX/DEX could release an effective working concentration in 60 min and sustain the drug release for at least 12 h. CGA-Lipo-MFX/DEX did not produce significant toxicities, but it increased cell numbers when co-cultured with ocular epithelial cells. An animal study also confirmed that CGA-Lipo-MFX/DEX could inhibit pathogen microorganism growth and improve corneal wound healing. Our results suggest that CGA-Lipo-MFX/DEX could be a useful anti-inflammatory formulation for ophthalmological disease treatment.

[Immunosuppression after corneal transplantation : Clinical standards and novel approaches]

Corticosteroid eye drops are the mainstay of immunosuppressive therapy after routine lamellar and perforating corneal transplantation. Commonly occurring side effects are cataract formation and increased intraocular pressure. Alternative immunosuppressive agents could allow the dosage of glucocorticoids to be reduced. The antibiotic azithromycin is a candidate drug that showed anti-inflammatory properties in cell cultures and animal models and has positive effects on transplant rejection.

Short-term azithromycin treatment promotes cornea allograft survival in the rat

Background

Any inflammatory response following corneal transplantation may induce rejection and irreversible graft failure. The purpose of this study is to analyze the anti-inflammatory effect of azithromycin (AZM) following experimental keratoplasty in rats.

Methods

Corneal transplants were performed between Fisher-donor and Lewis-recipient rats. Recipients were postoperatively treated three times daily with AZM, miglyol, ofloxacin or dexamethasone eye drops. As an additional control, AZM was applied following syngeneic keratoplasty. Furthermore, short-term treatments with AZM for seven days perioperatively or with AZM only three days prior to the transplantation were compared to appropriate controls. All transplants were monitored clinically for opacity, edema, and vascularization. Infiltrating CD45⁺, CD4⁺, CD8⁺, CD25⁺, CD161⁺ and CD163⁺ cells were quantified via immunohistochemistry.

Results

AZM significantly promoted corneal graft survival compared with miglyol or ofloxacin treatment. This effect was comparable to topical dexamethasone. No adverse AZM effect was observed. Histology confirmed a significant reduction of infiltrating leukocytes. The short-term application of AZM for three days prior to transplantation or for seven days perioperatively reduced corneal graft rejection significantly compared with the controls.

Conclusions

Along with antibiotic properties, topical AZM has a strong anti-inflammatory effect. Following keratoplasty, this effect is comparable to topical dexamethasone without the risk of steroid-induced adverse effects. Short-term treatment with AZM three days prior to the transplantation was sufficient to promote graft survival in the rat keratoplasty model. We therefore suggest further assessing the anti-inflammatory function of topical AZM following keratoplasty in humans.