BASIC INVESTIGATION
Impact of Iontophoresis and PACK-CXL Corneal
Concentrations of Antifungals in an In Vivo Model
Ayse Kalkanci, MD, PhD,* Nilufer Yesilirmak, MD,† Hüseyin Baran Ozdemir, MD,‡
Elif Ayca Unal, MD,* Merve Erdo gan, PhD,* Tamay Seker, PhD,§ Atakan Emre Tum, MS,¶
Ahmet Kamil Karakus, MS,¶ Kenan Hizel, MD,k and Kamil Bilgihan, MD**
Purpose: To investigate voriconazole (VRZ) penetration and
fungal load in the cornea after applying VRZ therapy with various
treatment combinations in a fungal keratitis model.
Methods: Fifty-four eyes of 27 young albino rabbits were provided
for this experimental study. Twelve corneas were inoculated with
Candida albicans, 12 corneas were inoculated with Fusarium solani,
and 6 eyes were selected as controls. Infected corneas received
various treatment combinations including VRZ 1% drop therapy
alone, VRZ 1% plus amphotericin B 1% drop combination therapy,
iontophoretic VRZ therapy, and VRZ 1% drop therapy after corneal
cross-linking. Fungal load was measured by log reduction, and VRZ
levels were quantified by liquid chromatography–tandem
mass spectrometry.
Results: Iontophoresis-assisted VRZ application showed the high-
est antifungal activity against F. solani keratitis (4-log reduction) and
C. albicans keratitis (5-log reduction) compared with other treatment
applications. VRZ levels were also found to be the highest in corneas
that received iontophoretic VRZ treatment (3.6313 6 0.0990 ppb for
F.solani keratitis and 1.7001 6 0.0065 ppb for C. albicans keratitis)
compared with other treatment applications.
Conclusions: Iontophoresis seems to provide the highest VRZ
concentration and highest antifungal activity in the cornea compared
with other treatment applications for C. albicans and F.
solani keratitis.
Key Words: keratitis, voriconazole, iontophoresis, corneal cross-
linking, liquid chromatography tandem mass spectrometry
(Cornea 2018;37:1463–1467)
F
ungal keratitis is a serious infection of the cornea that can
progress from corneal ulcer to corneal perforation rapidly
without proper treatment.
1
The most frequently encountered
pathogens are Fusarium spp, Candida albicans, and Asper-
gillus spp.
2,3
Most common risk factors for fungal keratitis
include ocular trauma, contact lens wear, ocular surgery,
immune system deficiency, prolonged use of corticosteroids,
and other ocular surface diseases.
3
Despite many studies and
these known factors, diagnosis of fungal keratitis remains
a challenge and the ideal therapeutic regimen is always
a matter of debate because of its difficulty.
4,5
After reliable and prompt diagnosis of fungal keratitis,
the first and commonly accepted approach is to start
appropriate intense medical treatment to prevent sight-
threatening complications.
5
There are various antifungal
agents
6
in clinical use [such as azoles, natamycin, amphoter-
icin B (AMB), etc.], and voriconazole (VRZ: triazole
antifungal agent derived from fluconazole) is suggested as
superior to others in recent years for severe fungal keratitis.
6,7
Application of topical VRZ or other agents often requires
hospitalization because of its intensive regimen (hourly use
for several days).
8
Still, penetration and absorption of topi-
cally applied drugs deep into the cornea are limited because of
the corneal barrier function associated with epithelial tight
junctions and high electrical resistance.
9,10
Thus, approaches
to increase drug absorption such as iontophoresis have
attracted great attention.
11,12
Iontophoresis is a technique based on the basic
electrical principle that oppositely charged ions attract
each other and similarly charged ions repel each another.
In this technique, ionized substances are driven into the
tissue by electrorepulsion at either the anode for positively
charged drugs or the cathode for negative drugs.
13
Ionto-
phoresis has been studied for drug delivery in ophthalmol-
ogy since 1943.
14
In this noninvasive method, molecules
can be transported actively across the cornea or conjunctiva
with application of an external electric field.
13
It has been
demonstrated that drugs can be maintained in ocular tissues
for hours after iontophoresis, and this drug loading can
increase by changing the current density and treatment
Received for publication January 30, 2018; revision received May 25, 2018;
accepted May 27, 2018. Published online ahead of print August 29, 2018.
From the *Department of Medical Microbiology, Gazi University Faculty of
Medicine, Ankara, Turkey; †Department of Ophthalmology, Yildirim
Beyazit University, Ankara, Turkey; ‡Ankara Ulucanlar Eye Training
and Research Hospital, University of Health Science, Ankara, Turkey;
§Middle East Technical University, Central Laboratory, Molecular
Biology-Biotechnology Research and Development Center, Mass Spec-
troscopy Laboratory, Ankara, Turkey; ¶Gazi University Faculty of
Medicine, Phase 4 Student, Ankara, Turkey; kDepartment of Infectious
Diseases, University Faculty of Medicine, Ankara, Turkey; and
**Department of Ophthalmology, Gazi University Faculty of Medicine,
Ankara, Turkey.
This project was supported by an unrestricted grant from Pfizer Inc.
The authors have no conflicts of interest to disclose.
Presented as a poster in “Trends in Medical Mycology, TIMM”; October 6–9,
2017; Belgrade, Serbia.
Correspondence: Ayse Kalkanci, MD, PhD, Department of Medical
Microbiology, Gazi University Faculty of Medicine, Ankara, Turkey
06500 (e-mail: aysekalkanci@email.com).
Copyright © 2018 Wolters Kluwer Health, Inc. All rights reserved.
Cornea
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