Design and Application of Multi-Center Clinical Research Platform for Phenotyping of Voriconazole Hepatotoxicity.

We introduce a phenotyping pipeline for voriconazole hepatotoxicity based on a multi-center clinical research platform. Using the platform's queue construction, feature generation, and feature screening functions, 52 features were obtained for model training. The prediction model of voriconazole hepatotoxicity was obtained by using the model training and evaluation functions of the platform. Important risk factors and protection factors of the model were listed.

Evaluation of antifungal activity, mechanisms of action and toxicological profile of the synthetic amide 2-chloro-N-phenylacetamide.

Aspergillus niger causes infections such as otitis and pulmonary aspergillosis in immunocompromised individuals. Treatment involves voriconazole or amphotericin B, and due to the increase in fungal resistance, the search for new compounds with antifungal activity has intensified. In the development of new drugs, cytotoxicity and genotoxicity assays are important, as they allow predicting possible damage that a molecule can cause, and in silico studies predict the pharmacokinetic properties. The aim of this study was to verify the antifungal activity and the mechanism of action of the synthetic amide 2-chloro-N-phenylacetamide against Aspergillus niger strains and toxicity. 2-Chloro-N-phenylacetamide showed antifungal activity against different strains of Aspergillus niger with minimum inhibitory concentrations between 32 and 256 µg/mL and minimum fungicides between 64 and 1024 µg/mL. The minimum inhibitory concentration of 2-chloro-N-phenylacetamide also inhibited conidia germination. When associated with amphotericin B or voriconazole, 2-chloro-N-phenylacetamide had antagonistic effects. Interaction with ergosterol in the plasma membrane is the probable mechanism of action.2-Chloro-N-phenylacetamide has favorable physicochemical parameters, good oral bioavailability and absorption in the gastrointestinal tract, crosses the blood-brain barrier and inhibits CYP1A2. At concentrations of 50 to 500 µg/mL, it has little hemolytic effect and a protective effect for type A and O red blood cells, and in the cells of the oral mucosa it promotes little genotoxic change. It is concluded that 2-chloro-N-phenylacetamide has promising antifungal potential, favorable pharmacokinetic profile for oral administration and low cytotoxic and genotoxic potential, being a promising candidate for in vivo toxicity studies.

Toxicity of simultaneous intrastromal and intracameral injection of voriconazole on corneal endothelium in a rabbit model.

PURPOSE: To investigate the toxicity of repeated simultaneous intrastromal and intracameral injections of voriconazole in corneal endothelial cells in a rabbit model. METHODS: Thirty-six eyes of 18 New Zealand white rabbits (six eyes per group) were divided into 6 groups according to the concentration of voriconazole (Group A, 0%; Group B, 0.05%; Group C, 0.1%; Group D, 0.25%; Group E, 0.5%; Group F, 1%). A combination of intrastromal and intracameral voriconazole injections were administrated to the eyes of each group three times on days 0, 3, and 7. Corneal clouding grades and central corneal thickness (CCT) were examined on days 0, 3, 7, 10, and 14. The endothelial cell counts (ECC) were measured on days 0 and 14. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were performed on day 14. RESULTS: Group F (1%) showed more severe corneal clouding than the other groups (Groups A-E) from day 7 (p < 0.05, respectively). There were no significant differences in CCT and ECC among the six groups at any time point (p > 0.05, respectively). SEM revealed blurring of the cell border and loss of microvilli at concentrations ≥0.25% (Groups D-F). TEM revealed microstructural changes in endothelial cells at concentrations ≥0.1% (Groups C-F), and multiple vacuoles were observed at a concentration of 1% voriconazole (Group F). CONCLUSIONS: Repeated simultaneous intrastromal and intracameral voriconazole injections at a concentration of 0.1% or higher induced microstructural endothelial damage in rabbit corneal endothelial cells.

How to disinfect anuran eggs? Sensitivity of anuran embryos to chemicals widely used for the disinfection of larval and post-metamorphic amphibians.

Emerging infectious diseases are major drivers of global and local amphibian biodiversity loss. Therefore, developing effective disinfection methods to manage the impact of diseases in wild and captive "ark" populations are an important goal in amphibian conservation. While chemical disinfectants have been used safely and effectively in larval and adult amphibians infected with pathogenic microbes, their applicability to amphibian egg masses has remained untested. To bridge this gap, we exposed embryos of the common toad (Bufo bufo) and agile frog (Rana dalmatina) experimentally to three widely used disinfectants: voriconazole, chloramphenicol and chlorogen-sesquihydrate. For 3 days we exposed portions of egg masses to these disinfectants at 1×, 2×, 5× and 10× the concentration recommended for the disinfection of tadpoles and adults. Subsequently, we recorded embryonic and larval survival, as well as larval body mass and the incidence of abnormalities 12 days after hatching. Application of voriconazole had species- and concentration-dependent negative impacts on survival and body mass, and caused marked malformations in the viscerocranial structure of B. bufo tadpoles. Exposure to chlorogen-sesquihydrate also resulted in significant mortality in B. bufo embryos and negatively affected body mass of R. dalmatina larvae. Chloramphenicol had little negative effects on embryos or larvae in either species. Based on these results, the application of voriconazole and chlorogen-sesquihydrate cannot be recommended for the disinfection of amphibian eggs, whereas treatment with chloramphenicol appears to be a safe method for eliminating potential pathogens from anuran egg masses and their immediate aquatic environment.

Improvement of the pharmacokinetic/pharmacodynamic relationship in the treatment of invasive aspergillosis with voriconazole. Reduced drug toxicity through novel rapid release formulations.

Voriconazole (VCZ) is currently the first-line treatment for invasive aspergillosis, although the doses are limited by its poor solubility and high hepatic toxicity. The aim of this study was to develop a solid self-dispersing micellar system of VCZ to improve the pharmacokinetic/pharmacodynamic (PK/PD) relationship and reduce hepatotoxicity. In this work, solid micellar systems of VCZ are formulated with different polysorbate 80 ratios using mannitol as a hydrophilic carrier. The novel micellar systems were characterized by scanning electron microscopy (SEM), powder X-ray diffraction (PXRD), differential scanning calorimetry (DSC) and dissolution studies. Self-dispersing micellar systems reduced VCZ crystallinity, leading to an improvement in its dissolution rate. The in vitro susceptibility test also revealed that the most common microorganisms in invasive aspergillosis exhibited low minimum inhibitory concentration (MIC) values for micellar systems. Pharmacokinetic studies indicated an improvement in bioavailability for MS-1:3:0.05, and changes in its biodistribution to different organs. MS-1:3:0.05 showed an increased concentration in lungs and a significant decrease in VCZ accumulated in the liver.

Formulation and characterization of voriconazole nanospray dried powders.

Purpose: Voriconazole nanoparticles (API-NPs) were prepared by nanospray drying to improve the solubility of voriconazole and reduce its interindividual variability.Methods: The preparation procedure was optimized by central composite design-response surface methodology. The properties of the nanoparticles were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), differential scanning calorimetry (DSC), and Fourier transform infrared (FTIR) analyses. The solubility, dissolution, and stability of the API-NPs were determined experimentally. The pharmacokinetics were assessed based on rat plasma levels of voriconazole. An acute oral toxicity test of the API-NPs was performed in mice.Results: The powers were formulated using cetyltrimethylammonium chloride (CTAC) as the carrier material. SEM and particle size results showed that the API-NPs had a narrow particle size distribution. The XRD, DSC, and FTIR analyses show a decrease in crystallinity and a polymorphic transformation of the nanoparticles after nanospray drying. The solubility in water was approximately 15 times higher than that of voriconazole. The API-NP tablets exhibited significantly higher plasma exposure, namely, longer acting times and lower variability. The acute administration of voriconazole showed no toxic histopathological effects on organ tissue.Conclusion: The solubility of voriconazole was greatly improved, it showed higher bioavailability and safety, and the interindividual variability in voriconazole pharmacokinetics was reduced by nanospray drying.

Metabolomics Investigation of Voriconazole-Induced Hepatotoxicity in Mice.

Voriconazole (VCZ) is a widely used triazole drug for the treatment of serious incidence of invasive fungal infections (IFIs), and its most commonly reported clinical side effect is hepatotoxicity. The mechanism of VCZ-induced hepatotoxicity is unclear, and no specific marker can be used for prediction and diagnosis. This study aims to apply the targeted metabolomics approach to identify specific VCZ-induced metabolites related to hepatotoxicity via liquid chromatography-triple quadrupole mass spectrometry (LC-QqQ-MS) in a C57BL/6 mouse model. Mice treated with three repeated doses of 40 mg/kg VCZ by tail vein injection to induce hepatotoxicity (VCZ-induced hepatotoxicity group, n = 8) were compared with mice without treatment (control group, n = 10). Both liver tissue and plasma were collected and analyzed to propose underlying mechanisms associated with VCZ-induced hepatotoxicity. The results indicated that the metabolites associated with oxidative stress were altered, and alterations in the metabolites involved in glutathione biosynthesis were noticed. The ratio of glutamine to glutamate showed a significant reduction in the VCZ-induced hepatotoxicity group compared to the control group, suggesting that glutamine might be transformed into glutamate for glutathione biosynthesis. Accordingly, we proposed that VCZ-induced hepatotoxicity is associated with oxidative stress to cause cell dysfunction, leading to alterations in energy metabolism, the urea cycle, and nucleoside metabolism. To the best of our knowledge, this is the first study to apply metabolomics for investigating the mechanism of VCZ-induced hepatotoxicity.

The effect of topical voriconazole on conjunctiva in rats as revealed by histopathology and immunohistochemistry.

The aim of this study was to evaluate the effects of topical voriconazole with histopathological and immunohistochemical analysis of the conjunctiva in rats. Twenty-eight Sprague Dawley rats were divided into four groups as two study (S1, S2) and two control (C1, C2). Voriconazole was instilled four times daily to S1, S2 rats. Physiologic saline (0.9%) was instilled four times daily in C1 and C2 rats. S1 and C1 were followed in a dark room; S2 and C2 were held in a room with sunlight. Impression cytology was performed at 0, 15, 30, 45 and 60th d after instillations. After 2 months of treatment conjunctival tissue was removed for histological and immunohistochemical analysis. In impression cytology evaluation, there was no difference between S1 and S2. At 60 d the difference between S1 and C1 was significant. In other comparisons, there was no difference between S1 and C1, C2. The scores of S2 was higher than C1 and C2 for all comparisons except 15th day scores of S2 and C2. In study groups, epithelial and gland degeneration were higher in S2, but inflammation scores were similar. The comparison of immunreactivity of ERK, TGFß and E-cadherin were different in the study groups than the control groups for all comparisons. In conclusion, voriconazole has side effects due to phototoxicity including squamous cell carcinoma. Clinicians should particularly be careful with the long-term use of topical voriconazole and should follow-up patients strictly in terms of ocular surface alterations.

Toxicity studies for the use of prodrug of voriconazole in rats.

It has been reported that voriconazole is used to treat infections caused by invasive aspergillosis, fluconazole-resistant Candida, Actinoplanes and Fusarium. This study was performed to investigate the safety of prodrug of voriconazole (POV) and explore the distribution and metabolism of POV in vivo. The POV for injection was formulated into POV injection. In this study, POV injection was given intravenously at the doses of 0, 30, 60, and 120 mg/kg/d to SD rats for 4 weeks consecutively. Toxicokinetic study was also performed to explore its distribution and metabolism. POV injection was found to be safe and well tolerated. Some statistically significant differences in relative liver weight were observed and several cases of hepatocyte hypertrophy occurred after the 4-week POV injection treatment. Liver-related toxic response could be reversed after recovery period. The results of toxicokinetics showed that POV can rapidly converts to voriconazole in SD rats after administration. The exposure of voriconazole in each group was significantly different between male and female rats. The results showed that the target organ for the toxic effect of POV is liver and the no-toxic-reaction-dose for long-term administration of POV injection was 60 mg/kg/d.

Photochemical and Pharmacokinetic Characterization of Orally Administered Chemicals to Evaluate Phototoxic Risk.

This study aimed to verify the applicability of a proposed photosafety screening system based on a reactive oxygen species (ROS) assay and a cassette-dosing pharmacokinetic (PK) study to chemicals with wide structural diversity. The orally taken chemicals, erythromycin, gatifloxacin, 8-methoxypsoralen (MOP), pirfenidone (PFD), trifluoperazine (TFP), and voriconazole (VRZ), were selected as test compounds. The ROS assay was conducted to evaluate their photoreactivity, and all test compounds excluding erythromycin generated significant ROS under simulated sunlight exposure. According to the ROS data, TFP had potent photoreactivity, and the photoreactivity of 4 other compounds was judged to be moderate. Regarding the oral cassette-dosing PK test in rats, the skin deposition of MOP, PFD, and VRZ was relatively high, and gatifloxacin and TFP exhibited moderate skin deposition properties. Based on the ROS and PK data of test compounds, PFD and TFP were judged to be potent phototoxic compounds, and MOP and VRZ were deduced to have phototoxic risk. The predicted phototoxic risk of test compounds by proposed screening was mostly in agreement with observed in vivo phototoxicity in the rat skin. The proposed screening system could provide reliable photosafety information on orally administered compounds with wide structural diversity.

Topically applied 1% voriconazole induces dysplastic changes on the ocular surface: animal study.

PURPOSE: To identify the risk of inducing ocular surface dysplasia following topical administration of 1% voriconazole eye drop. METHODS: Fourteen noninflamed healthy eyes of 14 white adult New Zealand rabbits were included in the study. The rabbits were randomly divided into two groups comprised of 7 rabbits each. Group 1 received topical 1% voriconazole and Group 2 received topical saline as the control group. In all animals, right eye was selected for the study. In Group 1 (Voriconazole Group), single drop of voriconazole was instilled every 10 min consecutively for 17 times a day for 60 days. In Group 2 (Control Group), single drop of saline was instilled every 10 min consecutively for 17 times a day for 60 days. At two months, animals were sacrificed and study eyes were enucleated with the eyelids. The specimens were stained with hematoxylin-eosin and histopathologic changes in cornea, bulbar and palpebral conjunctiva were evaluated under light microscope. RESULTS: There were no macroscopically visible lesions on the ocular surface of any rabbits. Histopathological evaluation showed mild to moderate dysplasia localized mainly in the limbus and extending to the adjacent cornea and bulbar conjunctiva in all rabbits in Voriconazole Group. Severe dysplasia or carcinoma in situ was not observed. In the Control Group, dysplasia was not observed, at all. CONCLUSION: This animal study provides a possible relationship between topically administered 1% voriconazole and ocular surface dysplasia. We recommend ophthalmologists to be aware of the risk of ocular surface dysplasia in patients received voriconazole eye drop.

Voriconazole treatment in adults and children with hematological diseases: can it be used without measurement of plasma concentration?

Indication and timing of trough plasma-voriconazole (VCZ)-concentration (t-PVC) measurement during VCZ treatment is a debated issue. Patterns of t-PVC were prospectively evaluated in pediatric (50 courses) and adult (95 courses) hematologic patients. Efficacy patterns were defined: adequate, t-PVC always ≥1 mcg/ml; borderline, at least one t-PVC measurement <1 mcg/ml but median value of the measurements ≥1 mcg/ml; inadequate, median value of the measurements <1 mcg/ml. Toxicity patterns were defined: favorable, t-PVC always ≤5 mcg/ml; borderline, one or more t-PVC measurements >5 mcg/ml but median value of the measurements ≤5 mcg/ml; unfavorable, median value of the measurements >5 mcg/ml. In children and adults the mean t-PVCs were higher during intravenous treatments. The t-PVC efficacy pattern was adequate, borderline and inadequate in 48%, 12%, and 40% of courses, respectively, in children, and in 66.3%, 16.8%, and 16.8% of courses, respectively, in adults. Adequate efficacy pattern was more frequent in children with body weight above the median (≥25 kg) (OR 4.8; P = .011) and in adults with active hematological disease receiving intravenous therapy (OR 3.93; P = .006). Favorable toxicity pattern was more frequent in children receiving VCZ daily dosage below the median (<14 mg/kg) (OR 4.18; P = .027) and in adults with body weight below the median (<68 kg) (OR 0.22; P = .004). T-PVC measurement is generally needed, however, a non t-PVC guided approach may be considered in heavier adults receiving intravenous VCZ. The risk of supratherapeutic levels does not seem an absolute indication for t-PVC monitoring.

Novel fluconazole derivatives with promising antifungal activity.

The fungistatic nature and toxicity concern associated with the azole drugs currently on the market have resulted in an increased demand for new azole antifungal agents for which these problematic characteristics do not exist. The extensive use of azoles has resulted in fungal strains capable of resisting the action of these drugs. Herein, we report the synthesis and antifungal activity of novel fluconazole (FLC) analogues with alkyl-, aryl-, cycloalkyl-, and dialkyl-amino substituents. We evaluated their antifungal activity by MIC determination and time-kill assay as well as their safety profile by hemolytic activity against murine erythrocytes as well as cytotoxicity against mammalian cells. The best compounds from our study exhibited broad-spectrum activity against most of the fungal strains tested, with excellent MIC values against a number of clinical isolates. The most promising compounds were found to be less hemolytic than the least hemolytic FDA-approved azole antifungal agent voriconazole (VOR). Finally, we demonstrated that the synthetic alkyl-amino FLC analogues displayed chain-dependent fungal membrane disruption as well as inhibition of ergosterol biosynthesis as possible mechanisms of action.

How common is subsequent central nervous system toxicity in asymptomatic patients with haematologic malignancy and supratherapeutic voriconazole serum levels?

OBJECTIVES: We sought to determine the frequency at which patients with elevated voriconazole (VRC) levels but no clinically evident central nervous system (CNS) toxicity subsequently develop CNS toxicity. METHODS: We retrospectively reviewed the records of adult patients with haematolologic malignancy who had a VRC serum level >5.5 µg/mL at MD Anderson Cancer Center (January 2010 to December 2015). Patients with any documented CNS toxicity at the time the VRC level was obtained or patients whose VRC was discontinued as a response to high VRC level were excluded. Neurologic status was assessed using standard grading scales. Demographic and clinical characteristics, including potentially interacting medications, were correlated with the development of toxicity. RESULTS: We identified 320 such patients (mean age, 57 ± 15 years; 202 male (63%)). Subsequent CNS toxicity was documented in only 16 patients (5%). The most common CNS toxicities were visual disturbances (9/16, 56%), depressed consciousness (5/16, 31%) and cognitive disturbance (4/16, 19%). Patients with CNS toxicity tended to be older than those without (64 ± 8 vs 57 ± 15 y, p 0.08). The use of one or more neurotoxic drugs was common in patients with subsequent CNS toxicity (14/16, 88%). Reduction of VRC dose associated with the high VRC level did not correlate with less subsequent CNS toxicity. CONCLUSIONS: Development of subsequent CNS toxicity is uncommon in haematolologic malignancy patients with elevated VRC levels who had no evidence of toxicity at the time the level was obtained. Automatic reduction of VRC dose out of concern for impending CNS toxicity might not be warranted.

In vitro assessment of non-irritant microemulsified voriconazole hydrogel system.

Research was aimed on microemulsion-based hydrogel for voriconazole. Oleic acid and isopropyl myristate as lipid phases; tween 20: tween 80 as surfactants and PEG600 as cosurfactant were selected to formulate voriconazole microemulsions. The promising microemulsions in terms of zeta potential, pH, viscosity, and drug release were selected and developed into hydrogels using carbopol 934. Resulting microemulsion-based hydrogel (MBH) of voriconazole were evaluated for in vitro diffusion and ex vivo permeation. Antifungal potentials of MBH were assessed against selected fungal strains. Optimal MBH formulations, O6 and O8 had displayed their antifungal potentials with enlarged zone of inhibition against selected fungal strains.

Voriconazole-Loaded Nanostructured Lipid Carriers for Ocular Drug Delivery.

PURPOSE: To design and evaluate the potential of a topical delivery system for ocular administration of voriconazole, based on cationic nanostructured lipid carriers (NLCs). METHODS: NLC dispersions composed of glyceryl behenate/capric caprylic triglyceride, polysorbate 80, sorbitan trioleate, and cetylpyridinium chloride were obtained and characterized. Ex vivo permeations experiments were performed to evaluate their drug delivery potential. RESULTS: NLCs presented a mean diameter of 250.2 ± 03.1 nm, narrow polydispersity index (0.288 ± 0.03), positive zeta potential (31.22 ± 3.8 mV), and over 75% encapsulation efficiency. Ex vivo ocular experiments proved that NLCs were able to deliver therapeutically relevant drug amounts to the cornea after only 30 minutes (13.88 ± 0.24 µg/cm). CONCLUSIONS: The formulation was nonexpensive, easy to prepare, and composed of well-tolerated and accepted excipients. Further in vivo experiments are necessary to confirm the improved performance and tolerability of the formulation.

Cytotoxic Effect of Voriconazole on Human Corneal Epithelial Cells.

BACKGROUND: To assess the cytotoxic properties of voriconazole and sulfobutylether-ß-cyclodextrin (SBECD) on cultured primary human corneal epithelial cells. METHODS: Human corneal epithelial cells were cultured and exposed to various concentrations of SBECD (0.016-32 mg/ml) and voriconazole (0.001-2 mg/ml). Cellular cytotoxicity of SBECD and voriconazole on human corneal epithelial cells was evaluated using the 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide test and the LIVE/DEAD Viability/Cytotoxicity Assay with fluorescence microscopy analysis. Cell damage was assessed with phase-contrast microscopy after 24 h of exposure to SBECD and voriconazole. RESULTS: The cytotoxicity tests and the morphological characteristic demonstrated the dose-dependent toxic effect of SBECD and voriconazole on human corneal epithelial cells. No corneal epithelial cytotoxicity was observed below the concentration of 0.08 and 0.025 mg/ml after 24-hour exposure to SBECD and voriconazole, respectively. CONCLUSIONS: The results of the study reveal the dose-dependent cytotoxic effect of SBECD and voriconazole on cultured human corneal epithelial cells. Therefore, voriconazole eye drops should be used cautiously in the treatment of fungal corneal ulcers.

In vitro and in vivo study on the effect of antifungal agents on hematopoietic cells in mice.

Liposomal amphotericin B, voriconazole, and caspofungin are currently used for systemic and severe fungal infections. Patients with malignant diseases are treated with granulocyte-colony stimulating factor (G-CSF) for the recovery of granulocytes after chemotherapy or hematopoietic cell (HC) transplantation. Since they have a high incidence of fungal infections, they inevitably receive antifungal drugs for treatment and prophylaxis. Despite their proven less toxicity for various cell types comparatively with amphotericin B and the decrease in the number of leukocytes that has been reported as a possible complication in clinical studies, the effect of liposomal amphotericin B, voriconazole, and caspofungin on HCs has not been clarified. The present study aimed to examine the in vitro and in vivo effect of these three modern antifungals on HCs. Colony-forming unit (CFU) assays of murine bone marrow cells were performed in methylcellulose medium with or without cytokines and in the presence or absence of various concentrations of liposomal amphotericin B, voriconazole, and caspofungin. In the in vivo experiments, the absolute number of granulocytes was determined during leukocyte recovery in sublethally irradiated mice receiving each antifungal agent separately, with or without G-CSF. In vitro, all three antifungal drugs were nontoxic and, interestingly, they significantly increased the number of CFU-granulocyte-macrophage colonies in the presence of cytokines, at all concentrations tested. This was contrary to the concentration-dependent toxicity and the significant decrease caused by conventional amphotericin B. In vivo, the number of granulocytes was significantly higher with caspofungin plus G-CSF treatment, higher and to a lesser extent higher, but not statistically significantly, with voriconazole plus G-CSF and liposomal amphotericin B plus G-CSF treatments, respectively, as compared with G-CSF alone. These data indicate a potential synergistic effect of these antifungals with the cytokines, in vitro and in vivo, with subsequent positive effect on hematopoiesis.

Voriconazole, an antifungal triazol that causes visual side effects, is an inhibitor of TRPM1 and TRPM3 channels.

PURPOSE: Administration of voriconazole, an antifungal triazole, causes transient visual disturbances in patients and attenuates the b-wave of the ERG. We sought to identify the retinal target of voriconazole underlying the effect on the ERG b-wave. METHODS: Electroretinograms were recorded from mice before and after intraperitoneal injection of voriconazole. The effect of voriconazole on ON-bipolar cells was tested by patch-clamp recordings of ON-bipolar cells in mouse retinal slices. Effects of voriconazole on mGluR6 and TRPM3 were assessed by patch-clamp recordings of Chinese hamster ovary (CHO) and HEK293 cells transfected with either TRPM3 or mGluR6 plus Kir3.1/Kir3.4. RESULTS: Voriconazole attenuated the ERG b-wave in mice, and inhibited ON-bipolar cell responses evoked by application of CPPG, an mGluR6 antagonist, onto the ON-bipolar cell dendrites, indicating that voriconazole blocks a step in the mGluR6-TRPM1 signal transduction pathway. Voriconazole almost completely blocked capsaicin-activated currents in ON-bipolar cells, which have been attributed to direct activation of the TRPM1 cation channel. Furthermore, application of voriconazole to CHO cells expressing TRPM3, a closely related channel to TRPM1, showed that voriconazole reversibly blocked pregnenolone sulfate-stimulated TRPM3 currents in transfected cells. In contrast, voriconazole only slightly inhibited mGluR6-mediated activation of G-protein activated inward rectifier potassium (GIRK) currents in cotransfected cells, suggesting that mGluR6 is not the primary target of voriconazole in ON-bipolar cells. CONCLUSIONS: The visual disturbances associated with voriconazole are likely due to block of TRPM1 channels in retinal ON-bipolar cells. Other neurological effects of voriconazole may be due to block of TRPM3 channels expressed in the brain.

Toxicity of topical antifungal agents to stratified human cultivated corneal epithelial sheets.

PURPOSE: Prolonged use of topical antifungal agents may compromise corneal epithelial integrity. Here, we used an in vitro model of human stratified corneal epithelium to compare the ocular toxicity profiles of 4 different antifungal eye drops. METHODS: Human corneal epithelial cell sheets were cultured in a serum-free medium containing 0.1% micafungin, 1% voriconazole, 5% pimaricin, 0.1% amphotericin B, or controls (saline or 5% glucose). Cell viability and barrier function were measured by WST-1 assay and carboxyfluorescein permeability assay, respectively. Cell migration was measured on a wound healing assay. RESULTS: WST-1 assay and carboxyfluorescein permeability assay revealed that amphotericin B was the most toxic drug, followed by pimaricin, micafungin, and voriconazole. Cell migration on a wound healing assay was decreased in the following order, amphotericin B, pimaricin, micafungin, and voriconazole. CONCLUSIONS: Topical micafungin and voriconazole appeared to be the least toxic to the corneal epithelium. Drug prescription should consider not only fungal species and susceptibility but also ocular toxicity and stage of treatment.