Ocular Fungal Infections Research Articles

A hospital-based observational comparative study of efficacy of intracameral voriconazole and oral ketoconazole in deep keratomycosis

Background: Fungal keratitis, one of the most common causes of ocular mycosis, is the second most common cause of blindness in the world, after cataracts. The aim of the study was to compare the efficacy of conventional topical, systemic medications and intracameral voriconazole injection in visual and structural outcomes in keratomycosis. Material and methods: We conducted a hospital-based observational study of 45 patients of 45 eyes with smear-positive fungal keratitis. Patients were categorized into three groups: Group I received systemic topical with oral ketoconazole 200 mg, Group II — topical medications with intracameral voriconazole 50 μgm/0.1 mL, Group III — topical medications with both oral ketoconazole 200 mg and intracameral voriconazole 50 μgm/0.1 mL. Results: The common fungal organism is identified as Fusarium. The mean final visual acuity (VA) was 1.25 ± 0.32, 1.47 ± 1.05, and 1.22 ± 0.37 logMAR in Group I, group II, and Group III, respectively. The mean improvement in VA was 0.33 ± 0.07, 0.01 ± 0.71, and –0.19 ± 0.02 logMAR without significant change (p = 0.9). There was a significant difference in VA between the final postoperative follow-up period and baseline in Group I cases (p = 0.0019). Whereas no difference in VA between the final postoperative follow-up period and baseline in either Group II (p = 0.0671) or Group III (p = 0.1505) cases. The difference in time between the disappearance of hypopyon and the mean time to infection healing was not statistically significant (p = 0.1). Three cases in each group were perforated, and keratoplasty was performed. These perforated cases did not show culture positive. Histopathology identified the isolated organisms as Aspergillus species (n = 3) and Fusarium species (n = 2) in the corneal buttons. Conclusion: The differences in VA between the three methods were not statistically significant, indicating no treatment method superior to others (inter-group). However, in Group I, there was a significant difference in VA between the final postoperative follow-up period and baseline (p = 0.0019). There was no difference in VA between these time intervals in either Group II (p = 0.0671) or Group III (p = 0.1505). Within-group or intra-group analysis reveals that the Group I method is more effective for VA. The success rate of the method depended cumulatively on the duration of intracameral voriconazole in the anterior chamber, non-drainage of hypopyon, and individual clinical response.

Miconazole Nitrate loaded Soluplus®-Pluronic® nano-micelles as promising Drug Delivery Systems for Ocular Fungal Infections: In vitro and In vivo Considerations

Miconazole nitrate (MN) is a broad-spectrum antifungal agent which suffers poor solubility and impermeability to the ocular tissue which limits its use in the treatment of ocular infections especially fungal keratitis, which is considered one of the most prevailing ocular infections. The current study aims to utilize polymeric mixed nano-micelles for the ocular delivery of MN using 33 full factorial design by varying the ratios of Pluronic® P123, Pluronic® F127, and Tetronic® T701 while the monitored responses were particle size, cloud point (CP), encapsulation efficiency (%EE) and %released at 6 hours (%Q6) at pH 7.4. The optimized formula was incorporated with Soluplus® (SP) to further enhance the (%EE) and the resultant formula was assessed in vitro as well as in vivo against C. albicans in treatment of induced ocular candidiasis using rabbits as a model animal. Results revealed that the optimized formula which comprised F127 and P123 in a ratio of (2:1) when incorporated with SP (SP-MPM) resulted in an increase in %EE from 35.12±3.18 to 99.19±7.03 with a particle size of 44.39±2.68nm with a sustained release profile and stability for 3 months at 4±2°C. In vivo results demonstrated the enhanced ability of SP-MPM for treatment of ocular candidiasis with enhanced % inhibition and susceptibility to C. albicans compared to 0.2% MN suspension confirmed with histopathological examination of rabbit’s eyes after 7 days of treatment with the absence of any degenerative effect to the ocular tissue. Thus, it can be concluded that SP-pluronic mixed nano-micelles offer a successful and stable ocular delivery platform for antifungal drug MN ensuring both its safety and efficacy.

A sensitive and rapid bioanalytical method for the quantitative determination of luliconazole in rabbit eye tissues using UPLC-MS/MS assay

Luliconazole (LCZ) is a novel antifungal imidazole with broad-spectrum and high susceptibility of Aspergillus and Fusarium are the dominant species of fungal keratitis, may potentially be a new medical treatment option for ocular fungal infection. To evaluate LCZ distribution in ocular tissues after topical application for the development of ophthalmic delivery system, it is important to have a bioanalytical method for measuring the drug concentrations in different ocular tissues and aqueous humor (AH). A selective and sensitive ultrahigh performance liquid chromatography coupled with tandem mass spectrometry (UPLC-MS/MS) method was developed for the quantification of LCZ in rabbit ocular tissues, including conjunctiva, cornea, AH, iris, lens, vitreous humor (VH), retinal choroid and sclera, using lanoconazole as internal standard (IS). Chromatographic separation was achieved on a Xterra MS, C18 column (2.1 × 50 mm, 3.5 μm) using mobile phase with formic acid solution (0.2%, v/v): acetonitrile (50:50, v/v) at a flow rate of 0.2 ml/min, and the run time was 2.5 min. Detection was performed using the transitions 354.1 → 150.3 m/z for LCZ and 320.1 → 150.3 m/z for IS by positive ion electrospray ionization in multiple reaction monitoring (MRM) mode. Method validation was conducted in accordance with U.S. Food and Drug Administration’s regulatory guidelines for bioanalytical method validation. The calibration curves were linear over the concentration range from 2.80 ng/ml to 2038 ng/ml for conjunctiva, cornea and sclera, 2.09 ng/ml to 1019 ng/ml for AH, 2.09 ng/ml to 509.5 ng/ml for iris, 2.09 ng/ml to 203.8 ng/ml for retinal choroid and VH, 2.04 ng/ml to 101.9 ng/ml for lens, with all the squared correlation coefficients (r2) more than 0.99. The accuracy of the method was within the acceptable limit of 89.34%∼112.78% at the lower limit of quantification and other concentrations, Inter-day and intra-day precision values, expressed in terms of RSD (%), in all tissues were within 15% at all concentrations. The mean recoveries of LCZ in rabbit ocular tissues was 84.85%∼100.52%. No interference was found due to matrix components. Luliconazole was stable during the stability studies, including autosampler stability, benchtop stability, freeze/thaw stability and long-term stability. The method was successfully applied to the ocular pharmacokinetic and tissues distribution studies of LCZ in rabbit after topical administration of LCZ ophthalmic drug delivery system.

Formulation and characterization studies of inclusion complexes of voriconazole for possible ocular application

In our study, Voriconazole (VOR) was selected as an active agent to be used for the treatment of ocular fungal infections. To overcome low aqueous solubility of VOR, inclusion complexes with α-cyclodextrin (α-CD), β-cyclodextrin (β-CD), γ-cyclodextrin (γ-CD), hydroxypropyl-cyclodextrin (HP-CD), hydroxypropyl-β-cyclodextrin (HP-β-CD) hydroxypropyl-γ-cyclodextrin (HP-γ-CD), methyl-β-cyclodextrin (M-β-CD) and sulfabutylether-β-cyclodextrin (SBE-β-CD) were formulated. Characterization studies revealed that inclusion complexes were formulated successfully with the lyophilization method. Aqueous solubility of VOR was enhanced up to 86 fold with the formation of the inclusion complexes. MTT analyses results revealed the safety of the complexes on 3T3 mouse fibroblast cell lines while Microbroth Dilution Method revealed the remarkable antifungal activities of the complexes. Analyses results revealed that inclusion complexes will overcome the poor ocular bioavailability of VOR resulting inefficient treatment of severe ocular fungal infections.

The facilitating effect of blue light on the antifungal agent susceptibilities of passaged conidia from the ocular-derived Fusarium solani species complex.

The eye is a light-receiving organ and has anatomical advantages to accept phototherapy. Fungi colonizing on the eyes, which cause ocular mycoses, are affected by daily blue light and could easily accept additional light irritation. Ocular mycoses are recalcitrant and blindness-causing eye diseases, and antifungal agent treatments are insufficient. Our team previously found that blue light could inhibit Fusarium solani hyphal growth but promote conidiation. Here, we investigated the antifungal susceptibilities and biological characteristics of the passaged conidia. Twelve Fusarium solani strains (11 ocular-derived strains and 1 standard laboratory strain) were inoculated under blue light (0.5 mW/cm2) and darkness conditions, respectively, to obtain the passaged conidia of blue light group (n = 12) and darkness group (n = 12). Two groups were tested to determine the growth abilities and in vitro antifungal susceptibilities to five antifungal drugs (voriconazole (VRC), amphotericin B (AMB), terbinafine (TRB), caspofungin (CAS), and 5-flucytosine (5FC)), which were examined by microscopy for morphological observation and spectrophotometry for turbidity analysis. The results showed that blue light group passaged conidia were more sensitive to antifungal drugs (AMB, VRC, TRB, and CAS) compared to darkness group. The MIC50 of VRC significantly decreased after blue light treatment (P < 0.05). The fungal inhibition rate significantly increased for VRC, AMB, and TRB in the low concentration range (P < 0.05 or P < 0.01). Blue light did not affect germination or hyphal extension of passaged conidia. These results suggested that blue light could facilitate fungal inhibition effect of AMB, VRC, TRB, and CAS and may improve the therapeutic efficiency in VRC and AMB clinical applications. Blue light phototherapy may provide a new adjuvant approach for the treatment of ocular mycosis.

Amphotericin B Polymer Nanoparticles Show Efficacy against Candida Species Biofilms.

Purpose: Chronic infections of Candida albicans are characterised by the embedding of budding and entwined filamentous fungal cells into biofilms. The biofilms are refractory to many drugs and Candida biofilms are associated with ocular fungal infections. The objective was to test the activity of nanoparticulate amphotericin B (AmB) against Candida biofilms. Methods: AmB was encapsulated in the Molecular Envelope Technology (MET, N-palmitoyl-N-monomethyl-N,N-dimethyl-N,N,N-trimethyl-6-O-glycolchitosan) nanoparticles and tested against Candida biofilms in vitro. Confocal laser scanning microscopy (CLSM) imaging of MET nanoparticles’ penetration into experimental biofilms was carried out and a MET-AmB eye drop formulation was tested for its stability. Results: MET-AmB formulations demonstrated superior activity towards C. albicans biofilms in vitro with the EC50 being ~30 times lower than AmB alone (EC50 MET-AmB = 1.176 μg mL−1, EC50 AmB alone = 29.09 μg mL−1). A similar superior activity was found for Candida glabrata biofilms, where the EC50 was ~10× lower than AmB alone (EC50 MET-AmB = 0.0253 μg mL−1, EC50 AmB alone = 0.289 μg mL−1). CLSM imaging revealed that MET nanoparticles penetrated through the C. albicans biofilm matrix and bound to fungal cells. The activity of MET-AmB was no different from the activity of AmB alone against C. albicans cells in suspension (MET-AmB MIC90 = 0.125 μg mL−1, AmB alone MIC90 = 0.250 μg mL−1). MET-AmB eye drops were stable at room temperature for at least 28 days. Conclusions: These biofilm activity findings raise the possibility that MET-loaded nanoparticles may be used to tackle Candida biofilm infections, such as refractory ocular fungal infections.

Incidence of fungal keratitis in Libya: An epidemiological study

Objectives: The aim of this study was to assess the occurrence of eye fungal infection among patients attending the eye hospital in Tripoli city, Libya. Materials and Methods: Seventy-one patients with ocular fungal infections were subjected to clinical and microbiological investigations. They were selected from patients attending the Tripoli Eye Hospital. The specimens of the external ocular infections were collected using sterile swab and inoculated to different culture media. Data were presented as count and percentages. Results: The current findings showed that Aspergillus was the most common causative agent, being responsible for 91.54% of the all cases, followed by Candida albicans (8.46%). Conclusion: Occurrence of fungal keratitis gradually increased in the years after 2009, especially after 2013. Knowledge of the pathological course and clinical features of fungal keratitis will undoubtedly bead in early diagnosis and treatment, with reduction in ocular morbidity.

Rapidly dissolving microneedle patch of amphotericin B for intracorneal fungal infections

Chronic fungal infection of the cornea could lead to blindness if not treated properly. Topical amphotericin B (AMP-B) is considered the first treatment of choice for ocular fungal infection. However, factors related to its poor solubility and penetration through intact cornea lead to poor bioavailability. Microneedles (MNs) are emerging as a minimally invasive method to enhance ocular drug delivery. This study aims to investigate the potential use of biodegradable poly(vinylpyrrolidone) (PVP) and hyaluronic acid (HA)–based rapidly dissolving MNs for delivery of AMP-B to treat fungal infection. The data obtained illustrates PVP/HA MN arrays’ reproducibility, good mechanical strength, and faster dissolution with 100% drug recovery. Multiphoton microscopic results revealed that MNs successfully penetrate the corneal tissue and enhance AMP-B permeation through corneal layers. Furthermore, PVP/HA MN arrays showed high solubility. Both PVP and HA successfully decreased AMP-B cytotoxicity when compared to free drug. More interestingly, the biocompatible MN formulations preserved the antifungal activity of AMP-B, as demonstrated by significant inhibition of fungal growth. Therefore, this study shows the feasibility of ocular delivery of the poorly soluble AMP-B using a fast-dissolving MN patch.Graphical abstract

Studying the ophthalmic toxicity potential of developed ketoconazole loaded nanoemulsion in situ gel formulation for ophthalmic administration

Ocular fungal infections are one of the essential reasons for vision loss, especially in developing countries for tropical regions. Ketoconazole (KZ), a broad-spectrum antifungal drug, is a lipophilic compound and practically insoluble in water. Since topical ophthalmic drug delivery confronts low bioavailability, an in situ gel formulation is designed to improve the residence time and consequently the bioavailability. Safety of the developed formulation as a carrier for ophthalmic drug delivery was measured using three different methods: MTT assay for measuring cell viability in which the human retinal pigmentation epithelial cells (RPE) were used, HET-CAM as a borderline method between in vivo and in vitro techniques for investigating the irritation potential of the chosen formulation which was done by adding formulation directly on the CAM surface and visually monitoring the vessels in terms of irritation reactions, and finally the modified Draize test for evaluating tolerability of the selected formulation on eyes. According to our results from the MTT test, cell viability for KZ-NE in situ gel formulation at 0.1% concentration was acceptable. The results obtained from the HET-CAM investigation didn’t show any sign of vessel injury on the CAM surface for prepared formulation. Additionally, during 24 hours, the developed formulation was tolerable by rabbit eyes. Regarding our results, KZ-NE in situ gel formulation was non-irritant and non-toxic and can be well-tolerated and presented as an applicable vehicle for ophthalmic delivery of the anti-fungal drug.

Antimicrobial nanomedicine for ocular bacterial and fungal infection.

Ocular infection induced by bacteria and fungi is a major cause of visual impairment and blindness. Topical administration of antibiotics remains the first-line treatment, as effective eradication of pathogens is the core of the anti-infection strategy. Whereas, eye drops lack efficiency and have relatively low bioavailability. Intraocular injection may cause concurrent ocular damage and secondary infection. In addition, antibiotic-based management can be limited by the low sensitivity to multidrug-resistant bacteria. Nanomedicine is proposed as a prospective, effective, and noninvasive platform to mediate ocular delivery and combat pathogen or even resistant strains. Nanomedicine can not only carry antimicrobial agents to fight against pathogens but also directly active microbicidal capability, killing pathogens. More importantly, by modification, nanomedicine can achieve enhanced residence time and release time on the cornea, and easy penetration through corneal tissues into anterior and posterior segments of the eye, thus improving the therapeutic effect for ocular infection. In this review, several categories of antimicrobial nanomedicine are systematically discussed, where the efficiency and possibility of further embellishment and improvement to adapt to clinical use are also investigated. All in all, novel antimicrobial nanomedicine provides potent and prospective ways to manage severe and refractory ocular infections.

Posaconazole micelles for ocular delivery: in vitro permeation, ocular irritation and antifungal activity studies.

Posaconazole (PSC) is a triazole group anti-fungal agent with the widest spectrum. Although there is no commercially available ocular dosage form, its diluted oral suspension preparation (Noxafil®) is used as off-label in topical treatment of severe keratitis and sclerokeratitis in the clinic. However, ocular bioavailability of PSC suspension form is extremely low due to its highly lipophilic character. Thus, there is a clinical need to improve its ocular bioavailability and to develop novel delivery system for the treatment of ocular fungal infections. Herein, we studied ex vivo permeation, penetration, anti-fungal activity, and Hen's Egg Test-Chorioallantoic Membrane (HET-CAM) toxicity tests in order to assess ocular targeting of PSC micelles, which were optimized in our previous study. The results indicated that micellar carrier system increased the permeability of PSC to eye tissues. Micelles showed higher affinity to ocular tissues than that of commercial oral suspension of PSC (Noxafil®). In vitro anti-fungal activity data also confirmed the efficacy of PSC loaded micellar formulations against Candida. albicans strains. The relative safety of the optimized micelles on the ocular tissue was shown with the HET-CAM toxicity test. In conclusion, micellar systems could be a promising strategy for the effective and safe delivery of PSC in the treatment of ocular fungal infections.

Fungal infections of the eye

Fungi are living organisms that are useful in the nature for cellulose degradation and decay of organic matter. They are useful for antibiotic synthesis and food maturation. At the same time there are several species that are pathogenic to man, animals and plants. They can cause infections in ocular tissues such as cornea, sclera, choroides, retina and vitreous. Fortunately, fungal infections are not frequent and are basically opportunistic infections. The exogenous infection is more common in tropical and subtropical parts of the world owing to their abundance in the environment as saprophytes. Prolonged treatment with corticosteroids or broad spectrum antibiotics, diabetes, acquired immunodeficiency syndrome, organ transplantation, malignancy and immunodeficiency conditions are some of the risk factors that may contribute to fungal infections. This review article is confined to ocular fungal infections, their pathogenesis, epidemiology, clinical features and laboratory diagnosis in brief. By far, fungal infections are easier to diagnose than treat. Availability of antifungal drugs is limited and a majority of them have serious side effects. Antifungal susceptibility testing is not common and data related to the development of resistance are meagre. Ophthalmic preparations for the treatment of fungal infections of the eye are very few and off label use of systemic antifungals as topical drugs is common. The science of fungal ocular infections is still evolving, with increasing data coming from just a few countries.

Voriconazole Ternary Micellar Systems for the Treatment of Ocular Mycosis: Statistical Optimization and InVivo Evaluation.

Voriconazole (VRC) is a broad spectrum, second generation triazole antifungal. The main use of VRC is via the oral and intravenous route. The study aimed to formulate VRC into ternary micellar systems (TMSs) for the topical treatment of ocular mycosis. TMSs were successfully prepared by water addition/solvent evaporation method, applying a 3-factor D-optimal design. The numerical optimization process suggested an optimal formula (OTMS) composed of total Pluronics to drug weight ratio of 22.89: 1, 1:1 weight ratio of Pluronic® P123 and F68, and 2% w/v of Labrasol. OTMS had high solubilization efficiency of 98.0%, small micellar size of 21.8 nm and suitable zeta potential and polydispersity index values of -9.0 mV and 0.261, respectively. OTMS exhibited acceptable stability for 3months. Transmission electron microscopy demonstrated the spherical morphology of micelles. OTMS was expected to cause no ocular irritation or blurring in vision as reflected by pH and refractive index measurements. The histopathological study revealed the safety of OTMS for ocular use. The fungal susceptibility testing using Candida albicans demonstrated the superiority of OTMS to VRC suspension, with greater and more durable growth inhibition. Therefore, ocular application of optimized VRC-loaded TMSs can be a promising treatment for ocular mycosis.

A Review on Ocular Novel Drug Delivery Systems of Antifungal Drugs: Functional Evaluation and Comparison of Conventional and Novel Dosage Forms.

Ocular fungal infections affect more than one million people annually worldwide. They can lead to impaired vision or even complete blindness, so they should be treated immediately to prevent such consequences. Although topical administration has always been the most common route of ocular drug delivery owing to high patient acceptance, reduced side effects, and the possibility of self-administration, its limited ocular bioavailability poses a major challenge. As a result, attention has recently been drawn to the design and development of novel drug delivery systems (NDDS) that can overcome the challenges of conventional dosage forms. This research is the first to review and classify the studies which have designed and developed topical ocular NDDS with the aim to compare the performance and antifungal activity of these novel systems with conventional forms. According to the results, all studies seemed to confirm the superiority of NDDS over conventional forms in cases of released and permeated drug and antifungal activity. The NDDS were used specifically to improve ocular delivery by slowing down the release rate, increasing drug permeation, and subsequently increasing the antifungal effects of the active pharmaceutical ingredients. Hence, further studies on NDDS may aid the optimization of ocular drug delivery of antifungal drugs.

Epidemiological and Molecular Investigation of Ocular Fungal Infection in Equine from Egypt.

Diagnosis and treatment of ocular fungal infection in equine seems very challenging for owners and clinicians. The present study aimed to identify and characterize fungal species isolated from the eyes of clinically healthy and diseased equines (N = 100) from Dakahlia Governorate, Egypt. The work also involved morphological and molecular characterization of the major fungal species. In addition, correlations between the occurrence of isolated fungi and some of the potential risk factors were also investigated. Interestingly, the prevalence rate of ocular mycosis in all examined equines in the study was 28% and there were major clinical signs associated with ocular fungal infection. Moreover, the identified fungal species included Aspergillus flavus, A. fumigatus, A. niger, Penicillium spp., Mucor spp., and Alternari spp. with a corresponding prevalence rate of 63.9%, 27.8%, 15.3%, 18.1%, 13.9%, and 4.2%, respectively, in healthy equine eyes, while their prevalence in diseased equine eyes was 57.1%, 32.1%, 21.4%, 7.1%, 3.6%, and 0%. Furthermore, a statistical significant association (p < 0.05) was found between the frequency of isolation of A. fumigatus and Penicillium and several risk factors (breed, sex, and ground type), while the remaining risk factors and occurrence of fungi were not statistically correlated. A subset of the Aspergillus species samples positive by polymerase chain reaction (PCR) were sequenced and their phylogenetic analysis identified three species of Aspergillus. Taken together, our study provides novel data related to the occurrence of ocular mycosis in equine in Egypt. Given the zoonotic potential of some identified fungi, our data may be helpful for implementation of novel diagnostic and therapeutic strategies for combating this sight-threatening infection in equine.

Fungal Infections of the Eye

World-wide, ocular fungal infections (ophthalmic mycoses) are important causes of morbidity and blindness (or even life-threatening infections). There is a need to bring together a concise review covering the many recent advances and reports, as well as data from excellent studies carried out during the last decade. This report also provides new data from the latest understanding of the pathogenesis of both keratitis and endophthalmitis. The latest diagnostic modalities of fungal infections as well as fungal species identification have been reviewed. Information from the latest multi-centric drug trials has been reviewed. This report provides a synopsis of literature published within the last couple of decades, but specifically, noteworthy reviews and important studies. Emphasis is on mycotic keratitis (a significant public health problem in many countries and accounting for the majority of microbial keratitis—the second most common cause of blindness), as well as on endophthalmitis. Recent information on other ocular mycotic infections is also collated.

Optimization and Characterization of Aqueous Micellar Formulations for Ocular Delivery of an Antifungal Drug, Posaconazole.

Topical therapy is preferred for the management of ocular fungal infections due to its superiorities which include overcoming potential systemic side effects risk of drugs, and targeting of drugs to the site of disease. However, the optimization of effective ocular formulations has always been a major challenge due to restrictions of ocular barriers and physiological conditions. Posaconazole, an antifungal and highly lipophilic agent with broad-spectrum, has been used topically as off-label in the treatment of ocular fungal infections due to its highly lipophilic character. Micellar carriers have the potential to improve the solubility of lipophilic drugs and, overcome ocular barriers. In the current study, it was aimed optimization of posaconazole loaded micellar formulations to improve aqueous solubility of posaconazole and to characterize the formulations and to investigate the physical stability of these formulations at room temperature (25°C, 60% RH), and accelerated stability (40°C, 75% RH) conditions. Micelles were prepared using a thin-film hydration method. Pre-formulation studies were firstly performed to optimize polymer/surfactant type and to determine their concentration in the formulations. Then, particle size, size distribution, and zeta potential of the micellar formulations were measured by ZetaSizer Nano-ZS. The drug encapsulation efficiency of the micelles was quantified by HPLC. The morphology of the micelles was depicted by AFM. The stability of optimized micelles was evaluated in terms of particle size, size distribution, zeta potential, drug amount and pH for 180 days. In vitro release studies were performed using Franz diffusion cells. Pre-formulation studies indicated that single D-ɑ-tocopheryl polyethylene glycol succinate (TPGS), a combination of it and Pluronic F127/Pluronic F68 are capable of formation of posaconazole loaded micelles at specific concentrations. Optimized micelles with high encapsulation efficiency were less than 20 nm, approximately neutral, stable, and in aspherical shape. Additionally, in vitro release data showed that the release of posaconazole from the micelles was higher than that of suspension. The results revealed that the optimized micellar formulation of posaconazole offers a potential approach for topical ocular administration.

Self-nanoemulsifying System Optimization for Higher Terconazole Solubilization and Non-Irritant Ocular Administration.

Purpose: Eye drops’ formulations of poorly water-soluble drugs, offer the advantage of crossing the lipophilic cornea, but their limited aqueous solubility may lead to low ocular bioavailability limiting their therapeutic uses. Terconazole (TZ) is an antifungal drug with low aqueous solubility, restricting its application in ocular fungal infection. Thus, the aim of the work in this study is to enhance TZ solubilization, permitting better ocular permeation and higher bioavailability. To achieve this goal, different self-nanoemulsifying systems (SNESs) were prepared using different oils, surfactants and co-surfactants. Methods: Ternary phase diagrams were constructed to identify self nano-emulsification regions for each oil system examined; either Labrafil® M2125CS or Capryol™ 90. TZ saturated solubility in the different formulated systems were measured and systems showing highest potential for TZ solubilization were selected. The optimized systems were chosen based on their globule size, polydispersity index, self-emulsification characteristics. Finally, TZ release as well as the irritation effect via Hen’s Egg test-chorioallantoic membrane (HET-CAM test) of the optimized system was observed in vitro. Results: The optimized system was formulated using 20% w/w Labrafil® M2125 CS, 50% w/w Tween® 80 and 30% w/w Transcutol® HP. Oil globules showed size range of 15.13 nm and self-emulsification time of 12.80 seconds. The system released 100% of the drug within half an hour compared to 2 hours in case of TZ-suspension. Finally, HET-CAM test showed non-irritating response and normal vascularization of the chorioallantoic membrane. Conclusion: The formulated SNES could be a promising approach to enhance ocular efficacy of TZ.

Posaconazole loaded ocular inserts for antifungal activity

Corneal and conjunctival infections are common ocular diseases; however, sometimes lead to blindness when neglected. Despite most of the ocular drug delivery systems are in eye drop form, they suffer from poor retention on the ocular surface and low ocular bioavailability leading to unsatisfactory results even with repeated treatment. Therefore, there is a need for more effective drug delivery systems for the ocular application. The present study was carried out to demonstrate that ocular inserts effectively delivers a significant concentration of drug with topical administration for the treatment of fungal infections with the help of extended residence time on the ocular surface. Chitosan-based inserts were prepared by the freeze-drying method. The prepared inserts were evaluated for various parameters. Layered structures were revealed with scanning electron microscopy analyses. Thermal and structural behaviors were analyzed by differential scanning calorimetry and Fourier-transform infrared spectroscopy with nuclear magnetic resonance analyses, respectively. Drug contents were evaluated by a validated HPLC method. In vitro release studies were also performed in simulated tear fluid at 34±1°C for 48 hours. Analyses results revealed that chitosan-based ocular inserts were suitable systems for posaconazole delivery for the treatment of severe ocular fungal infections.

Updates in Ocular Antifungal Pharmacotherapy: Formulation and Clinical Perspectives

In this review, a compilation on the current antifungal pharmacotherapy is discussed, with emphases on the updates in the formulation and clinical approaches of the routinely used antifungal drugs in ocular therapy. Natamycin (Natacyn® eye drops) remains the only approved medication in the management of ocular fungal infections. This monotherapy shows therapeutic outcomes in superficial ocular fungal infections, but in case of deep-seated mycoses or endophthalmitis, successful therapeutic outcomes are infrequent, as a result of which alternative therapies are sought. In such cases, amphotericin B, azoles, and echinocandins are used off-label, either in combination with natamycin or with each other (frequently) or as standalone monotherapies, and have provided effective therapeutic outcomes. In recent times, amphotericin B, azoles, and echinocandins have come to occupy an important niche in ocular antifungal pharmacotherapy, along with natamycin (still the preferred choice in most clinical cases), in the management of ocular fungal infections.