Topical delivery of antifungal agents

Co-delivery of minoxidil and finasteride via ionic liquid and cyclodextrin-assisted in situ thermosensitive hydrogel for synergistic treatment of androgenic alopecia

Androgenic alopecia (AGA), the most prevalent type of progressive hair loss, currently lacks an effective topical treatment regimen. In this study, we synthesized an ionic liquid (IL) to co-solubilize minoxidil (MXD) and finasteride (FIN) and subsequently formulated them into an in situ thermosensitive ionic liquid/cyclodextrin/poloxamer hydrogel (ICPG), termed M + F@ICPG. M + F@ICPG was developed for the transdermal co-delivery of these two drugs, aiming to provide a multipath therapeutic approach for AGA while avoiding the adverse effects commonly associated with oral FIN and topical MXD tincture. The thermosensitive characteristics, skin penetration, hair follicle (HF) targeting efficiency, biosafety, and in vivo therapeutic efficacy of M + F@ICPG were evaluated using an AGA mouse model. Our results demonstrated that M + F@ICPG was a thermosensitive hydrogel, transitioning from solution to gel upon contact with the scalp. Compared to the FIN suspension and MXD tincture, M + F@ICPG significantly enhanced the skin penetration (∼2.2-fold) and retention (∼8.6-fold) of FIN and increased the relative retention of MXD (∼6.3-fold) in the skin. Moreover, M + F@ICPG exhibited a HF targeting index of 1.74 for MXD and 1.46 for FIN, indicating enhanced drug targeting to HF. M + F@ICPG showed superior in vivo efficacy in terms of hair regeneration, anagen recovery, inflammation mitigation, and microvessel reconstruction. The underlying mechanism was attributed to the upregulation of hair growth genes, downregulation of hair loss genes, and reduction of abnormally elevated inflammatory factors. These findings suggest that this novel M + F@ICPG is a promising topical co-delivery system for the synergistic treatment of AGA.

8-Hydroxyquinoline derivative as a promising antifungal agent to combat ocular fungal infections

Introduction. Ocular fungal infections are pathologies of slow progression, occurring mainly in the cornea, but can also affect the entire structure of the eyeball. The main aetiological agents are species of the genera Candida and Fusarium. Both diagnosis and treatment require speed and effectiveness. However, the currently available therapy basically consists of the use of azoles and polyenes, known for their low penetration into the ocular tissue and the associated toxicity.Hypothesis. Thus, new strategies to combat these infections are needed, such as the development of new antifungals or the use of associations.Aim. Thus, the compound PH151, derived from a promising class of 8-hydroxyquinolines, and natamycin, amphotericin B (AMB) and voriconazole (VRC), the main antifungals used in ocular antifungal therapy, were considered against Candida spp. and Fusarium spp.Methodology. The MICs of compound PH151 ranged from 1.0 to 16.0 µg ml-1, according to CLSI protocols.Results. The association of PH151 with AMB and VRC showed a synergistic effect for more than 50% of the strains tested.Conclusion. Both the compound alone and its association (VRC-AMB-PH151) demonstrated promising potential as an antifungal agent in ocular infections, since the evaluated ocular toxicity profile was positive and the compounds presented low toxicity.

Comparative Evaluation of Topical Monotherapy (Natamycin or Natasol) and Combination Therapy (Natamycin and Voriconazole) in Mild-Moderate Fungal Keratitis

PURPOSE

To compare the efficacy of monotherapy (natamycin 5% or Natasol 1%) versus combination therapy (natamycin 5% and voriconazole 1%) in the treatment of mild-moderate fungal keratitis.

METHODS

In a prospective, comparative, interventional study, 60 eyes of 60 patients with mild-moderate fungal keratitis were included and randomized in 3 groups based on the topical antifungal therapy received: group 1, natamycin 5%; group 2, Natasol 1% (1% w/v aqueous natamycin); and group 3, combination of natamycin 5% and voriconazole 1%.

RESULTS

51 of 60 cases (85%) resolved with medical management only. Trauma was the major predisposing factor. Aspergillus species was the most common organism isolated. There was comparable decrease in the corneal infiltrate area from 16.92 ± 7.24, 15.12 ± 7.15, and 20.39 ± 4.81 mm2 in groups 1, 2, and 3, respectively (P > 0.05) at all follow-ups [days 3, 7, 30, 60, and 90]. There was a trend of early reepithelization in the Natasol group. The area of epithelial defect was comparable at baseline among all 3 groups (P = 0.24) and was statistically smaller in the Natasol group at 1-month follow-up (P = 0.01). The duration to complete epithelization was shortest in the Natasol group (37 ± 10 days; P = 0.02) compared with group 1 (45 ± 12 days) and group 3 (49 ± 12 days). The corrected distance visual acuity improved significantly and comparably in all groups (P = 0.4).

CONCLUSIONS

Topical Natasol 1% tends to shorten the time to complete epithelization in cases of mild-moderate fungal keratitis compared with topical natamycin 5% and combination therapy of natamycin 5% and voriconazole 1%.

Antifungal activity of synthetic xanthenone against fluconazole-resistant Candida auris and its mechanism of action

Candida auris, an emerging multidrug-resistant fungal pathogen discovered in Japan in 2009, poses a significant global health threat, with infections reported in about 25 countries. The escalation of drug-resistant strains underscores the urgent need for new treatment options. This study aimed to investigate the antifungal potential of 2,3,4,4a-tetrahydro-1H-xanthen-1-one (XA1) against C. auris, as well as its mechanism of action and toxic profile. The antifungal activity of XA1 was first evaluated by determining the minimum inhibitory concentration (MIC), time-kill kinetics and biofilm inhibition. In addition, structural changes, membrane permeability, reactive oxygen species (ROS) production, and in vitro and in vivo toxicity of C. auris after exposure to XA1 were investigated. The results indicated that XA1 exhibited an MIC of 50 μg/mL against C. auris, with time-kill kinetics highlighting its efficacy. Field emission scanning electron microscopy (FE-SEM) showed structural damage in XA1-treated cells, supported by increased membrane permeability leading to cell death. Furthermore, XA1 induced ROS production and significantly inhibited biofilm formation. Importantly, XA1 exhibited low cytotoxicity in human epidermal keratinocytes (HaCaT), with a cell viability of over 90 % at 6.25 μg/mL. In addition, an LD50 of 17.68 μg/mL was determined in zebrafish embryos 24 h post fertilization (hpf), with developmental delay observed at prolonged exposure at 6.25 μg/mL (48-96 hpf). These findings position XA1 as a promising candidate for further research and development of an effective antifungal agent.

In vitro antifungal activity of polymeric nanoparticles loaded with Euphorbia tirucalli extract

The therapeutic potential of medicinal plants is known as an alternative in treatment of human affections; in effect, the conventional application of these medicinal sources has several limitations like low bioavailability, solubility and stability, which affect its pharmacological efficacy. In recent decades, extraordinary advances have been made in new drug delivery systems using nanocarriers. This work consisted in determining the in vitro antifungal activity of the methanolic extract of Euphorbia tirucalli formulated in polymeric nanoparticles. The antifungal activity was determined by the microdilution method in 96-well microplates, applying nanoparticles loaded with plant extract (NP-Ext) obtained by nanoprecipitation on clinical isolates of Trichophyton rubrum and T. interdigitalis. Regarding the nanoparticles, the lots used did not present significant differences in their physicochemical characteristics, with a size of 91.885 ± 1.621nm, polydispersity index of 0.152 ± 0.025 and Z-potential of -6.047 ± 0.987. The quantification of the extract in the polymeric matrix was determined by infrared spectroscopy (FTIR), where an efficiency and encapsulation percentage of 22.15 ± 0.82 and 2.95 ± 0.11, respectively, were obtained. The in vitro antifungal activity of the crude and formulated extract was obtained calculating the Minimum Inhibitory Concentration (MIC) of each one; a MIC of 125 µg/mL was obtained against T. rubrum and T. interdigitalis with the crude extract, while a MIC value of 55.55 and 0.1 µg/mL was obtained with NP-Ext, respectively, against these same. Conclusions: biological activity is closely linked to the phytochemical profile of the extract; while the improvement of said potential with the NP-Ext with the dosage form was directly related to the physicochemical characteristics of the nanocarrier.

Formulation and evaluation of itraconazole-loaded nanoemulgel for efficient topical delivery to treat fungal infections

Aim: The clinical application of conventional oral dosage form of itraconazole is limited due to its poor bioavailability. The aim of the study was to develop nanoemulgel of Itraconazole for topical delivery. Method: Nanoemulsions were prepared, optimized and further incorporated into a gel and evaluated for homogeneity, pH, viscosity, spreadability, in vitro drug release and skin irritation studies. Results: Cumulative drug release from nanoemulsions was within the range of 37.24 to 47.63% at 10 h. Drug release % for all the nanoemulgel formulations at10 h was 32.39, 39.75 and 45.9% respectively. Nanoemulgel was non-irritant as demonstrated by skin irritation studies in animals. Conclusion: Itraconazole nanoemulgels were proved to be potential for effective topical delivery of drug with enhanced bioavailability.

Treatments for Ocular Diseases in Pregnancy and Breastfeeding: A Narrative Review

Pregnancy is a medical condition in which the physiological changes in the maternal body and the potential impact on the developing fetus require a cautious approach in terms of drug administration. Individual treatment, a thorough assessment of the extent of the disease, and a broad knowledge of the therapeutic options and different routes of administration of ophthalmic drugs are essential to ensure the best possible results while minimizing risks. Although there are currently several routes of administration of drugs for the treatment of eye diseases, even with topical administration, there is a certain amount of systemic absorption that must be taken into account. Despite continuous developments and advances in ophthalmic drugs, no updated data are available on their safety profile in these contexts. The purpose of this review is both to summarize the current information on the safety of ophthalmic treatments during pregnancy and lactation and to provide a practical guide to the ophthalmologist for the treatment of eye diseases while minimizing harm to the developing fetus and addressing maternal health needs.

Superficial Dermatophytosis across the World's Populations: Potential Benefits from Nanocarrier-Based Therapies and Rising Challenges

The most prevalent infection in the world is dermatophytosis, which is a major issue with high recurrence and can affect the entire body including the skin, hair, and nails. The major goal of this Review is to acquire knowledge about cutting-edge approaches for treating dermatophytosis efficiently by adding antifungals to formulations based on nanocarriers in order to overcome the shortcomings of standard treatment methods. Updates on nanosystems and research developments on animal and clinical investigations are also presented. Along with the currently licensed formulations, the investigation also emphasizes novel therapies and existing therapeutic alternatives that can be used to control dermatophytosis. The Review also summarizes recent developments on the prevalence, management approaches, and disadvantages of standard dosage types. There are a number of therapeutic strategies for the treatment of dermatophytosis that have good clinical cure rates but also drawbacks such as antifungal drug resistance and unfavorable side effects. To improve therapeutic activity and get around the drawbacks of the traditional therapy approaches for dermatophytosis, efforts have been described in recent years to combine several antifungal drugs into new carriers. These formulations have been successful in providing improved antifungal activity, longer drug retention, improved effectiveness, higher skin penetration, and sustained drug release.

Reviving the interest in the versatile drug nystatin: A multitude of strategies to increase its potential as an effective and safe antifungal agent

Nystatin is an antifungal molecule with a remarkable yet squandered versatility. In this review, its mechanism of action is explored, along with its extensive action spectrum and toxicity. A multitude of methodologies to tackle the drug's physical and chemical hurdles are outlined along with some proven-effective strategies to increase its activity and/or decrease its toxicity. A separate detailed section focused on micro and nanotechnology solutions addresses new drug delivery systems made of polymeric, metallic or lipid materials. Although the topical route depicts greater representativeness amongst these formulations, the intravenous, dental, oral, vaginal and inhalation routes are also mentioned. The unsuccessful previous attempts at developing parenteral formulations of nystatin or even the withdrawal of a nystatin-loaded multilamellar liposome should not divert research away from this drug. In fact, the interest in nystatin ought to be reawakened with the ongoing clinical trials on the promising nystatin-like genetically engineered derivate BSG005.

Impact of Nystatin Oral Rinse on Salivary and Supragingival Microbial Community among Adults with Oral Candidiasis

This study aimed to evaluate the impact of Nystatin oral rinse on salivary and supragingival microbiota in adults with oral candidiasis and identify predictive factors related to individuals' responses to Nystatin. The trial involved twenty participants who used 600,000 International Units/application of Nystatin oral rinse for seven days, four times a day, and were followed up at one week and three months after the rinse. The salivary and plaque microbiome of the participants were assessed via 16S rDNA amplicon sequencing. Overall, salivary and plaque microbiomes remained stable. However, among the participants (53 percent) who responded to Nystatin rinse (defined as free of oral Candida albicans post treatment), Veillonella emerged as a core genus alongside Streptococcus and Actinomyces in supragingival plaque at the 3-month follow-up. Furthermore, statistical models were fit to identify predictive factors of Nystatin rinse success (elimination of C. albicans) or failure (remaining C. albicans). The results revealed that an increased level of salivary Interferon (IFN)-γ-inducible protein (IP-10), also known as C-X-C motif chemokine ligand 10 (CXCL10), was an indicator of a failure of responding to Nystatin rinse. Future clinical trials are warranted to comprehensively assess the impact of antifungal treatment on the oral flora.

Eye fungal infections: a mini review

Ocular fungal infections annually affect more than one million individuals worldwide. The management of these infections is problematic, mainly due to the limited availability of effective antifungal agents. Thus, ocular infections are increasingly recognized as important causes of morbidity and blindness, especially keratitis and endophthalmitis. Thus, this review aims to demonstrate the importance of fungal eye infections through the description of the main related aspects, with emphasis on the treatment of these infections. For this purpose, a search for scientific articles was conducted in databases, such as Medline, published from 2000 onwards, addressing important aspects involving fungal eye infections. In addition, this work highlighted the limited therapeutic arsenal available and the severity associated with these infections. Thus, highlighting the importance of constantly updating knowledge about these pathologies, as it contributes to agility in choosing the available and most appropriate therapeutic alternatives, aiming at positive and minimally harmful results for that particular patient.

Polymeric film containing pomegranate peel extract as a promising tool for the treatment of candidiasis

Polymeric films containing pomegranate peel extract (PPE) can act as a drug-delivery platform for topical treatment of candidiasis. The composition, mechanical resistance, and in vitro antifungal activity of a polymeric film containing PPE at 1.25 mg.mL^-1 were investigated. Films were prepared using a solvent casting technique. The incorporation of PPE in the polymeric matrix gave rise to homogeneous, smooth, shiny, and yellowish-brown films. FTIR spectra of the film containing PPE showed differences without compromising the stability of the extract and the matrix. SEM analysis showed the existence of interruptions in the continuity of the films with extract, which promoted a reduction in the mechanical parameters without significantly changing the tensile strength and elongation at break. Films showed adequate mechanical properties and antifungal activity against Candida albicans, C. glabrata, C. krusei and C. tropicalis.

Development of Miconazole Nitrate Nanoparticles Loaded in Nanoemulgel to Improve its Antifungal Activity

Miconazole is a synthetic derivative of imidazole, a medication with a broad-spectrum antifungal agent that is used to treat localized vaginal, skin, and nail infections. The aim of the study was to develop an innovative technique to improve the permeability and efficacy of topical miconazole nitrate. A nanoemulgel of miconazole nitrate was formulated by the incorporation of a nanoemulsion and a hydrogel. The nanoemulsion was first optimized using a self-emulsifying technique, and the drug was then loaded into the optimum formulation and evaluated prior to mixing with the hydrogel. Miconazole nitrate nanoemulgel formulations were evaluated for their physical characteristics and antifungal activity. Based on the results, the formulation with 0.4 % Carbopol showed the highest release profile (41.8 mg/ml after 2 h); thus, it was chosen as the optimum formulation. A cell diffusion test was performed to examine the ability of the Miconazole nitrate nanoemulgel to penetrate the skin and reach the bloodstream. Percentage cumulative drug releases of 29.67 % and 23.79 % after 6 h were achieved for the MNZ nanoemulgel and the commercial cream, Daktazol, respectively. The antifungal activity of the novel MNZ nanoemulgel formulation was tested against Candida albicans and compared to Daktazol cream and almond oil; the results were: 40.9 ± 2.3 mm, 25.4 ± 2.7 mm and 18 ± 1.9 mm, respectively. In conclusion, a novel MNZ nanoemulgel showing superior antifungal activity compared to that of the commercial product has been developed. This nanotechnology technique is a step toward making pharmaceutical dosage forms that has a lot of promise.

Combined Application of Tacrolimus with Cyproconazole, Hymexazol and Novel {2-(3-R-1H-1,2,4-triazol-5-yl)phenyl}amines as Antifungals: In Vitro Growth Inhibition and In Silico Molecular Docking Analysis to Fungal Chitin Deacetylase

Agents with antifungal activity play a vital role as therapeutics in health care, as do fungicides in agriculture. Effectiveness, toxicological profile, and eco-friendliness are among the properties used to select suitable substances. Furthermore, a steady supply of new agents with different modes of action is required to counter the well-known potential of human and phyto-pathogenic fungi to develop resistance against established antifungals. Here, we use an in vitro growth assay to investigate the activity of the calcineurin inhibitor tacrolimus in combination with the commercial fungicides cyproconazole and hymexazol, as well as with two earlier reported novel {2-(3-R-1H-1,2,4-triazol-5-yl)phenyl}amines, against the fungi Aspergillus niger, Colletotrichum higginsianum, Fusarium oxysporum and the oomycete Phytophthora infestans, which are notoriously harmful in agriculture. When tacrolimus was added in a concentration range from 0.25 to 25 mg/L to the tested antifungals (at a fixed concentration of 25 or 50 mg/L), the inhibitory activities were distinctly enhanced. Molecular docking calculations revealed triazole derivative 5, (2-(3-adamantan-1-yl)-1H-1,2,4-triazol-5-yl)-4-chloroaniline), as a potent inhibitor of chitin deacetylases (CDA) of Aspergillus nidulans and A. niger (AnCDA and AngCDA, respectively), which was stronger than the previously reported polyoxorin D, J075-4187, and chitotriose. The results are discussed in the context of potential synergism and molecular mode of action.

Alginate as a Promising Biopolymer in Drug Delivery and Wound Healing: A Review of the State-of-the-Art

Biopolymeric nanoparticulate systems hold favorable carrier properties for active delivery. The enhancement in the research interest in alginate formulations in biomedical and pharmaceutical research, owing to its biodegradable, biocompatible, and bioadhesive characteristics, reiterates its future use as an efficient drug delivery matrix. Alginates, obtained from natural sources, are the colloidal polysaccharide group, which are water-soluble, non-toxic, and non-irritant. These are linear copolymeric blocks of α-(1→4)-linked l-guluronic acid (G) and β-(1→4)-linked d-mannuronic acid (M) residues. Owing to the monosaccharide sequencing and the enzymatically governed reactions, alginates are well-known as an essential bio-polymer group for multifarious biomedical implementations. Additionally, alginate’s bio-adhesive property makes it significant in the pharmaceutical industry. Alginate has shown immense potential in wound healing and drug delivery applications to date because its gel-forming ability maintains the structural resemblance to the extracellular matrices in tissues and can be altered to perform numerous crucial functions. The initial section of this review will deliver a perception of the extraction source and alginate’s remarkable properties. Furthermore, we have aspired to discuss the current literature on alginate utilization as a biopolymeric carrier for drug delivery through numerous administration routes. Finally, the latest investigations on alginate composite utilization in wound healing are addressed.

Efficacy of oral nystatin treatment for patients with oral mucosal dysesthesia but without objective oral mucosal manifestations and necessity of Candida culture test before oral nystatin treatment

Background/purpose

Materials and methods

Results

Conclusion

Tea Tree Oil Nanoemulsion-Based Hydrogel Vehicle for Enhancing Topical Delivery of Neomycin

The present investigation aims to improve the antimicrobial influence of certain antibacterial drugs, namely, neomycin (NEO), exploiting the benefits of natural oils such as tea tree oil (TTO). Therefore, a distinctive nanolipid formulation, namely, a nanoemulsion (NE), was developed using a Central Composite Factorial Design (CCD) approach depending on the amount of TTO and tween 80 as surfactant. The optimized NEO-NE formula exhibiting minimum globular size and maximum in vitro release was selected. For efficient topical delivery, NEO-NE was incorporated into a pre-formulated hydrogel. The developed NEO-NE-hydrogel was characterized by its physical characteristics such as pH, viscosity, and spreadability. Next, it was tested for stability under different conditions for 3 months. Ultimately, an irritation test was conducted followed by an antibacterial examination. The preparation demonstrated acceptable properties to be successfully applied topically. It showed non-significant changes in stability in both conditions up to 3 months storage when compared to a fresh preparation. It exhibited no irritation when applied on hairless animal skin. Finally, TTO revealed a good inhibition for the bacterial growth that could improve the influence of NEO antibacterial activity, indicating the efficiency of NE containing NEO prepared with TTO to be a promising antibacterial nanocarrier.

Assessment of antifungal efficacy of itraconazole loaded aspasomal cream: comparative clinical study

Topical conveyance of antifungal agents like itraconazole ITZ has been giving good grounds for expecting felicitous antifungal medicines. The defiance of topical delivery of this poorly water soluble and high-molecular-weight drug, however, mightily entail an adequate vehiculation. ITZ aspasomes, newer antioxidant generation of liposomes, have been designed and enclosed in a cream to ameliorate skin deposition. The proposed creams containing non-formulated ITZ or encapsulated in aspasomes (0.1% or 0.5%) were topically applied in patients with diagnosed diaper dermatitis complicated by candidiasis, tinea corporis (TC), and tinea versicolor (TVC). Placebos (void aspasomal cream and cream base) were also utilized. The obtained results for diaper rash revealed that aspasomal cream (0.5% ITZ) was eminent with respect to complete cure and negative candida culture after 10-day therapy relative to counterparts containing 0.1% ITZ aspasomes or non-formulated ITZ (0.1% and 0.5%). For tinea, the same trend was manifested in terms of ‘cleared’ clinical response in 90% of patients and absence of fungal elements after 4-week treatment. Relative to non-formulated ITZ, ITZ aspasomal cream was endorsed to be auspicious especially when ITZ concentration was lowered to half commercially available cream concentration (1%), pushing further exploitation in other dermal fungal infections.

Cytotoxic mechanism of tioconazole involves cell cycle arrest at mitosis through inhibition of microtubule assembly

Tioconazole is one of the drugs used to treat topical mycotic infections. It exhibited severe toxicity during systemic administration; however, the molecular mechanism behind the cytotoxic effect was not well established. We employed HeLa cells as a model to investigate the molecular mechanism of its toxicity and discovered that tioconazole inhibited HeLa cell growth through mitotic block (37%). At the half-maximal inhibitory concentration (≈ 15 μM) tioconazole apparently depolymerized microtubules and caused defects in chromosomal congression at the metaphase plate. Tioconazole induced apoptosis and significantly hindered the migration of HeLa cells. Tioconazole bound to goat brain tubulin (K _d, 28.3 ± 0.5 μM) and inhibited the assembly of microtubules in the in vitro assays. We report for the first time that tioconazole binds near to the colchicine site, based on the evidence from in vitro tubulin competition experiment and computational analysis. The conformation of tubulin dimer was found to be "curved" upon binding with tioconazole in the MD simulation. Tioconazole in combination with vinblastine synergistically inhibited the growth of HeLa cells and augmented the percentage of mitotic block by synergistically inhibiting the assembly of microtubules. Our study indicates that the systemic adverse effects of tioconazole are partly due to its effects on microtubules and cell cycle arrest. Since tioconazole is well tolerated at the topical level, it could be developed as a topical anticancer agent in combination with other systemic anticancer drugs.

GRAPHICAL ABSTRACT

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s10616-021-00516-w.

Menthol in Combination with Iontophoresis Promotes Natamycin Penetration through the Cornea: In Vitro and In Vivo Studies

We studied whether menthol can promote penetration of natamycin, a representative antifungal macrolide agent, through the cornea. Natamycin penetration was examined using an in vitro iontophoresis system that simulates clinical scenario; menthol (0.1-0.3%, w/v) was added to the donor reservoir of a standard Franz diffusion chambers. In vivo effects of menthol on natamycin penetration were examined in a set of bioassays using rabbits inoculated with Aspergillus fumigatus in the right eye. Potential irritation to the rabbit eye was examined using a standard test. Menthol significantly (p<0.05) potentiated the effects of iontophoresis on natamycin penetration. The optimal combination seemed to be 0.2% menthol in combination with 3 mA/cm² iontophoresis.

CaCO3-based carriers with prolonged release property for antifungal drug delivery to hair follicles

Superficial fungal infections are of serious concern worldwide due to their morbidity and increasing distribution across the globe in this era of growing antimicrobial resistance. Delivery of antifungals to target...

Optical clearing of tissues: Issues of antimicrobial phototherapy and drug delivery

This review presents principles and novelties in the field of tissue optical clearing (TOC) technology, as well as application for optical monitoring of drug delivery and effective antimicrobial phototherapy. TOC is based on altering the optical properties of tissue through the introduction of immersion optical cleaning agents (OCA), which impregnate the tissue of interest. We also analyze various methods and kinetics of delivery of photodynamic agents, nanoantibiotics and their mixtures with OCAs into the tissue depth in the context of antimicrobial and antifungal phototherapy. In vitro and in vivo studies of antimicrobial phototherapies, such as photodynamic, photothermal plasmonic and photocatalytic, are summarized, and the prospects of a new TOC technology for effective killing of pathogens are discussed.

Design of transfersomal nanocarriers of nystatin for combating vulvovaginal candidiasis; A different prospective

The objective of this study was to prepare and evaluate Nystatin (NYS) loaded transfersomes to achieve better treatment of vulvovaginal candidiasis. Nystatin transferosomes were formulated utilizing thin film hydration method. A 3² full factorial design was employed to evaluate the effect of different formulation variables. Two independent variables were chosen; the ratio between lecithin surfactant (X₁) was set at three levels (10-40), and the type of surfactants (X₂) was set at three levels (Span 60, Span 85 and Pluronic F-127). The dependent responses were; entrapment efficiency (Y₁: EE %), vesicles size (Y₂: VS) and release rate (Y₃: RR). Design Expert® software was utilized to statistically optimize formulation variables. The vesicles revealed high NYS encapsulation efficiency ranging from 97.35 ± 0.03 to 98.01 ± 0.20% whereas vesicle size ranged from 194.8 ± 20.42 to 400.8 ± 42.09 nm. High negative zeta potential values indicated good stability of the prepared formulations. NYS release from transfersomes was biphasic and the release pattern followed Higuchi's model. The optimized formulation (F7) exhibited spherical morphology under transmission electron microscopy (TEM). In-vitro and in-vivo antifungal efficiency studies revealed that the optimized formula F7 exhibited significant eradication of candida infestation in comparison to free NYS. The results revealed that the developed NYS transfersomes could be a promising drug delivery system to enhance antifungal efficacy of NYS.

Fusarium Keratitis-Review of Current Treatment Possibilities

In many parts of the world, fungi are the predominant cause of infectious keratitis; among which, Fusarium is the most commonly isolated pathogen. The clinical management of this ophthalmic emergency is challenging. Due to the retardation of the first symptoms from an injury and the inability to differentiate fungal from bacterial infections based on clinical symptoms and difficult microbial diagnostics, proper treatment, in many cases, is postponed. Moreover, therapeutical options of Fusarium keratitis remain limited. This paper summarizes the available treatment modalities of Fusarium keratitis, including antifungals and their routes of administration, antiseptics, and surgical interventions.

A molecular mechanism investigation of the transdermal/topical absorption classification system on the basis of drug skin permeation and skin retention

A transdermal/topical absorption classification system for the characterization of the systemic or local delivery of drugs is the theoretical basis for the design and evaluation of transdermal/topical formulations. A classification system was established on the basis of the in vitro and in vivo skin permeation/retention behaviors of 12 model drugs. Drug skin penetration/retention exhibited a significant correlation with physicochemical parameters (log K_O/W, molecular weight, polar surface area, and polarizability). Four representative model drugs were selected to clarify the molecular mechanisms of drug skin permeation/retention behaviors. The excellent lipid-disrupting effect and enhanced partitioning exhibited by propranolol (high permeation-high retention) and zolmitriptan (high permeation-low retention) via the formation of moderate H-bonds with skin lipids were proven by ATR-FTIR (Δν_asCH2 > 2 cm^-1), Raman spectra (ΔLPP, SPP > 0.2 nm), and X-ray scattering (lipid crystallization) and were supported by ¹³C NMR results. The low lipid miscibility of zolmitriptan (ΔH_{zolmitriptan-lipid} = 126.92 J/g) caused the low skin retention of this drug. High polarizabiltiy (α = 38.5 × 10^-24 cm³) and low H-bond forming capability (E_H-bond = 0 kcal/mol) restricted terbinafine (low permeation-high retention) in terms of partitioning (k_D-SC = 0.09). Diclofenac (low permeation-low retention) stabilized skin lipids through the formation of strong H-bonds and exhibited excessive drug-lipid miscibility (ΔH_{diclofenac-skin} = -128.73 J/g), thus restricting its skin absorption. This classification system reflects the most essential drug skin absorption characteristics and provides a theoretical basis for the design of transdermal/topical formulations.

Lipid Nanoparticles Based Cosmetics with Potential Application in Alleviating Skin Disorders

The lipids mainly oils, fats, waxes and phospholipids are of substantial importance in the development and functioning of cosmetic products. The lipid nanoparticles-based cosmetic product is highly capable of protecting the skin against harmful radiations and is utilized for anti-aging therapy. Naturally derived antioxidants such as carotenoids, retinoids and tocopherols could be employed for their antioxidant properties as therapeutics and skincare active moieties in cosmetic products. Such a lipid nanoparticles-based cosmetic formulation consisting of antioxidants are very effective against irritated and inflamed skin and very promising for treating skin disorders such as atopic dermatitis and psoriasis. Therefore, the present review provides an insight into lipid nanoparticles based cosmetics and the mechanistic of their percutaneous absorption. The manuscript discussion highlights the role of lipid nanoparticles-based cosmetics/cosmeceuticals employing active ingredients of synthetic and natural origin in alleviating dermatological disorders and enhancing skin health and appeal. Furthermore, the manuscript also updates about contemporary research studies carried on the concept of lipid nanoparticles based formulation design of cosmetic preparation and significant outcome to alleviate skin disorders.

Nanoparticles as a Tool for Broadening Antifungal Activities

Fungal infections are diseases that are considered neglected although their infection rates have increased worldwide in the last decades. Thus, since the antifungal arsenal is restricted and many strains have shown resistance, new therapeutic alternatives are necessary. Nanoparticles are considered important alternatives to promote drug delivery. In this sense, the objective of the present study was to evaluate the contributions of newly developed nanoparticles to the treatment of fungal infections. Studies have shown that nanoparticles generally improve the biopharmaceutical and pharmacokinetic characteristics of antifungals, which is reflected in a greater pharmacodynamic potential and lower toxicity, as well as the possibility of prolonged action. It also offers the proposition of new routes of administration. Nanotechnology is known to contribute to a new drug delivery system, not only for the control of infectious diseases but for various other diseases as well. In recent years, several studies have emphasized its application in infectious diseases, presenting better alternatives for the treatment of fungal infections.

Dermatokinetic assessment of luliconazole-loaded nanostructured lipid carriers (NLCs) for topical delivery: QbD-driven design, optimization, and in vitro and ex vivo evaluations

The present study is concerned with the QbD-based design and development of luliconazole-loaded nanostructured lipid carriers (NLCs) hydrogel for enhanced skin retention and permeation. The NLCs formulation was optimized employing a 3-factor, 3-level Box-Behnken design. The effect of formulation variable lipid content, surfactant concentration, and sonication time was studied on particle size and % EE. The optimized formulation exhibited particle size of 86.480 ± 0.799 nm; 0.213 ± 0.004 PDI, ≥ - 10 mV zeta potential and 85.770 ± 0.503% EE. The in vitro release studies revealed sustained release of NLCs up to 42 h. The designed formulation showed desirable occlusivity, spreadability (0.748 ± 0.160), extrudability (3.130 ± 1.570), and the assay was found to be 99.520 ± 0.890%. The dermatokinetics assessment revealed the C_{max Skin} to be ~ 2-fold higher and AUC_0-24 to be ~ 3-fold higher in the epidermis and dermis of NLCs loaded gel in contrast with the marketed cream. The T_max of both the formulations was found to be 6 h in the epidermis and dermis. The obtained results suggested that luliconazole NLCs can serve as a promising formulation to enhance luliconazole's antifungal activity and also in increasing patient compliance by reducing the frequency of application.

Chlorhexidine for the Treatment of Fusarium Keratitis: A Case Series and Mini Review

Fungal keratitis is difficult to treat, especially Fusarium keratitis. In vitro studies show that chlorhexidine could be an interesting option as monotherapy. We describe a case series of four patients (four eyes) with Fusarium keratitis at Radboud University Medical Center (Nijmegen, the Netherlands). The patients were treated with chlorhexidine 0.02% eye drops. The in vitro activity of eight antifungals and chlorhexidine was determined according to the European Committee on Antimicrobial Susceptibility Testing (EUCAST) broth microdilution method. We also reviewed the literature on the use of chlorhexidine in the treatment of fungal keratitis. Topical chlorhexidine was well tolerated, and all patients showed complete resolution of the keratitis upon treatment with chlorhexidine. A PubMed search of the available literature was conducted (last search 8 March 2020) and yielded two randomized clinical trials (natamycin versus chlorhexidine) and one case report addressing the treatment of fungal keratitis with chlorhexidine. Chlorhexidine was found to be safe with regard to toxicity and to be superior to natamycin in the clinical trials. Chlorhexidine showed in vitro fungicidal activity against Fusarium and clinical effectiveness in our cases, supporting further clinical evaluation. Advantages of chlorhexidine are its topical application, its general availability, its low costs, its broad-spectrum activity, and its fungicidal mechanism of action at low concentrations.

Enhanced in vivo antifungal activity of novel cell penetrating peptide natamycin conjugate for efficient fungal keratitis management

Natamycin is the only FDA approved drug that is used as a first line of treatment for fungal keratitis caused by filamentous fungi, however natamycin is known for poor corneal penetration. Cell penetrating peptides (CPPs) are emerging nanocarriers for the enhanced delivery of various macromolecules owing to their distinct cellular translocation ability. In the present study, tissue penetration ability and antifungal efficacy of CPP (Tat₂) conjugated natamycin has been investigated and compared with natamycin alone in vivo. Results show that Tat₂natamycin exhibits five- fold higher ocular penetration than natamycin alone when given topically. Complete resolution of fungal keratitis in 44% of the animals in Tat₂natamycin treated group as compared to only 13% of the animals in natamycin treated group further highlights its increased antifungal efficacy. Hence, this conjugate is a promising antifungal molecule with enhanced ocular penetration as well as antifungal efficacy against selected fungal species.

Nanoliposome-loaded antifungal drugs for dermal administration: A review

Cutaneous fungal infections are the fourth most common health problem, which involves approximately one billion people worldwide. Drug delivery to the skin seems to be the best choice for superficial fungal infections. Topical formulations can release a sufficient amount of drug in therapeutical concentrations and permeate higher layers of the skin like the stratum corneum. As the outermost layer of the epidermis, the stratum corneum prevents the drug from penetrating the skin. Liposomes, especially nanosized as topical drug delivery systems to the skin, can show various functions depending on their size, lipids and cholesterol components, the percent of ingredients, lamellarity, and surface charge. Nanoliposomes can increase permeation through the stratum corneum, decrease systemic effects with their localizing actions, and overcome many dermal drug delivery obstacles. Antifungal drugs, such as croconazole, econazole, fluconazole, ketoconazole, terbinafine hydrochloride, tolnaftate, and miconazole entrapped in liposomes have indicated improved skin penetration and localizing effects. According to the literature review summarized in this paper, many studies have identified liposomes as a powerful carrier for topical antifungal drug delivery to the skin. However, a few studies introduced new generations of liposomes like ethosomes and transfersomes. This paper was conducted on almost all liposomal studies of antifungal drugs with dermal application.

Sertaconazole induced toxicity in HeLa cells through mitotic arrest and inhibition of microtubule assembly

Econazole, miconazole, and sertaconazole, the structurally related azoles with imidazole moiety, were evaluated for their cytotoxicity and their ability to bind to mammalian tubulin. Our results indicated that sertaconazole and econazole bound to goat brain tubulin with a dissociation constant of 9 and 19 μM respectively, while miconazole did not bind to goat brain tubulin. Econazole, miconazole, and sertaconazole inhibited the proliferation of HeLa cells with an IC₅₀ of 28, 98, and 38 μM respectively with sertaconazole alone inducing a mitotic block in the treated cells. Since sertaconazole bound to goat brain tubulin with higher affinity and blocked the cells at mitosis, we hypothesized that its cytotoxic mechanism might involve inhibition of tubulin and econazole which did not block the cells at mitosis may have additional targets than tubulin. Sertaconazole inhibited the polymerization of tubulin in HeLa cells and the in vitro assembled goat brain tubulin. Competitive tubulin-binding assay using colchicine and computational simulation studies showed that sertaconazole bound closer to the colchicine site and induced the tubulin dimer to adopt a "bent" conformation which is incompetent for the polymerization. Results from RT-PCR analysis of the A549 cells treated with sertaconazole indicated activation of apoptosis. Sertaconazole significantly inhibited the migration of HeLa cells and showed synergistic antiproliferative potential with vinblastine. Collectively, the results suggest that sertaconazole which is already in clinical practice could be useful as a topical chemotherapy agent for the treatment of skin cancers in combination with other systemic anticancer agents.

Inhibition of Dermatophyte Fungi by Australian Jarrah Honey

Superficial dermatophyte infections, commonly known as tineas, are the most prevalent fungal ailment and are increasing in incidence, leading to an interest in alternative treatments. Many floral honeys possess antimicrobial activity due to high sugar, low pH, and the production of hydrogen peroxide (H2O2) from the activity of the bee-derived enzyme glucose oxidase. Australian jarrah (Eucalyptus marginata) honey produces particularly high levels of H2O2 and has been found to be potently antifungal. This study characterized the activity of jarrah honey on fungal dermatophyte species. Jarrah honey inhibited dermatophytes with minimum inhibitory concentrations (MICs) of 1.5-3.5% (w/v), which increased to ≥25% (w/v) when catalase was added. Microscopic analysis found jarrah honey inhibited the germination of Trichophyton rubrum conidia and scanning electron microscopy of mature T. rubrum hyphae after honey treatment revealed bulging and collapsed regions. When treated hyphae were stained using REDOX fluorophores these did not detect any internal oxidative stress, suggesting jarrah honey acts largely on the hyphal surface. Although H2O2 appears critical for the antifungal activity of jarrah honey and its action on fungal cells, these effects persisted when H2O2 was eliminated and could not be replicated using synthetic honey spiked with H2O2, indicating jarrah honey contains agents that augment antifungal activity.

Soft Malleable Vesicles: versatile carriers for efficient topical delivery of fungal therapeutics

Fungal infections have become a subject of great concern and the incidence of fungal infections is increasing, presenting an enormous challenge to healthcare professionals. Since most of the fungal infections are occurring over the skin, the treatment option of these infections always involves topical application. However, in topical delivery drug reaches into systemic circulation through different barriers of skin. Nevertheless, due to the low permeability, skin restricts the movement of many drugs. Hence, a delivery system is required, which deliver the medicament into the skin layers or through the skin and into the systemic circulation. Ethosomes or Soft malleable vesicles are the novel lipid vesicular carrier that offer improved skin permeability and efficient delivery due to their structure and composition. They contain high concentration of ethanol, which increases the fluidity of the skin. Therefore, in the present paper, we have explored the utility of ethosomal systems in the topical treatment of fungal infections. Structure, compositions types, mechanism and techniques of preparation of ethosome also discussed in the paper.

Prospective Nanotechnology-Based Strategies for Enhanced Intra- and Transdermal Delivery of Antifungal Drugs

Topical therapy of superficial fungal infections allows the prevention of systemic side effects and provides drug targeting at the site of disease. However, an appropriate drug concentration in these sites should be provided to ensure the efficacy of such local treatment. The enhancement of intra- and transdermal penetration and accumulation of antifungal drugs is an important aspect here. The present overview is focused on novel nano-based formulations served to improve antimycotic penetration through the skin. Furthermore, it summarizes various approaches towards the stimulation of drug penetration through and into the stratum corneum and hair follicles, which are considered to be promising for the future improvement of superficial antifungal therapy as providing the drug localization and prolonged storage property at the targeted area.

Liposomes: From Bangham to Supercritical Fluids

Liposomes are spherical vesicles made up of an aqueous core surrounded by phospholipids. These delivery systems (DS) are largely employed as drug carriers in several industrial fields, such as pharmaceutical and nutraceutical fields. The aim of this short review is to provide a fast overview on the main fundamentals of liposomes, thought as a compact guide for researchers and students that want to approach this topic for the first time. The mini-review will focus on the definitions, production methods and characterization protocols of the liposomes produced, making a critical comparison of the main conventional and supercritical based manufacturing methods available. The literature was analyzed deeply from the first works by Dr. Bangham in 1965 to the most recent supercritical fluid applications. The advantages and disadvantages of conventional and high-pressure processes will be described in terms of solvent elimination, production at the nanometric (50–300 nm) and micrometric level (1–100 μm) and encapsulation efficiency (20–90%). The first proposed methods were characterized by a low encapsulation efficiency (20–40%), resulting in drug loss, a high solvent residue and high operating cost. The repeatability of conventional processes was also low, due to the prevalent batch mode. Supercritical-assisted methods were developed in semi-continuous layouts, resulting in an easy process scale-up, better control of liposome dimensions (polydispersity index, PDI) and also higher encapsulation efficiencies (up to 90%).

Antifungal Resistance Regarding Malassezia pachydermatis: Where Are We Now?

Malassezia pachydermatis is a yeast inhabiting the skin and ear canals in healthy dogs. In the presence of various predisposing conditions it can cause otitis and dermatitis, which are treated with multiple antifungal agents, mainly azole derivatives. This manuscript aims to review the available evidence regarding the occurrence of resistance phenomena in this organism. Various findings support the capacity of M. pachydermatis for developing resistance. These include some reports of treatment failure in dogs, the reduced antifungal activity found against yeast isolates sampled from dogs with exposure to antifungal drugs and strains exposed to antifungal agents in vitro, and the description of resistance mechanisms. At the same time, the data reviewed may suggest that the development of resistance is a rare eventuality in canine practice. For example, only three publications describe confirmed cases of treatment failure due to antifungal resistance, and most claims of resistance made by past studies are based on interpretive breakpoints that lack sound support from the clinical perspective. However, it is possible that resistant cases are underreported in literature, perhaps due to the difficulty of obtaining a laboratory confirmation given that a standard procedure for susceptibility testing of M. pachydermatis is still unavailable. These considerations highlight the need for maintaining surveillance for the possible emergence of clinically relevant resistance, hopefully through a shared strategy put in place by the scientific community.

Keratin Biomembranes as a Model for Studying Onychomycosis

Difficulties in obtaining human nails that are large enough for examining the penetration of drug formulations led us to produce keratin films regenerated from human hair. We assume that these films can simulate human nail plates in drug penetration and permeation tests and can serve as a biological model for studying onychomycosis. The films were formed from keratin extracted from human hair using dithiothreitol, urea and thiourea. The obtained keratin extract was dispensed into Teflon rings and dried at 40 °C and then cured at 110 °C. The structure, surface morphology, chemical characterization and thermal stability of the films were characterized and were compared to those of human nail, hair and bovine hoof samples using SDS-electrophoresis, scanning electron microscopy (SEM), X-ray diffraction analysis (XRD), Fourier transform infrared spectroscopy (FTIR) and thermogravimetric analysis (TGA). The structure of the obtained films was found to be closer to human nails than to hair or bovine hooves. The keratin films were infected with Trichophyton rubrum and were proven to be appropriate for serving as a model for studying onychomycosis.

Ultrasound-Assisted Preparation of Exopolysaccharide/Nystatin Nanoemulsion for Treatment of Vulvovaginal Candidiasis

PURPOSE

As one of the classic anti-Canidia albicans (CA) and vulvovaginal candidiasis (VVC) drugs, nystatin (NYS) is limited by poor water solubility and easy aggregation. Traditional NYS vaginal delivery formulations do not fully adapt to the specific environment of the vaginal cavity. The use of exopolysaccharides (EPS) has great application potential in emulsifiers, but its use has not been reported in nanoemulsions. In this work, an EPS/NYS nanoemulsion (ENNE) was developed to improve the activities of NYS against CA and VVC.

METHODS

The ENNE was prepared by ultrasonic method using EPS as an emulsifier, liquid paraffin oil as an oil phase, PEG400 as a co-emulsifier, and NYS as the loaded drug. ENNE preparation was optimized by response surface method. After optimization, in vitro and in vivo analysis of the anti-CA activity; animal experiments; staining with propidium iodide (PI), periodic acid-schiff (PAS), and hematoxylin-eosin (H&E); and cytokine experiments were performed to investigate the therapeutic ability against VVC.

RESULTS

The optimal formulation and preparation parameters of ENNE were determined as follows: EPS content of 1.5%, PEG400 content of 3.2%, NYS content of 700 μg/mL, paraffin oil content of 5.0%, ultrasonic time of 15 min, and ultrasonic amplitude of 35%. The ENNE showed an encapsulated structure with an average particle size of 131.1 ± 4.32 nm. ENNE exhibited high storage and pH stability, as well as slow release. The minimum inhibitory concentration (MIC) of ENNE against CA was only 0.125 μg/mL and the inhibition zone was 19.0 ± 0.5 mm, for greatly improved anti-CA effect. The prepared ENNE destroyed the membrane of CA cells, and exhibited good anti-CA effect in vivo and therapeutic ability against VVC.

CONCLUSION

The results of this study will promote the application of EPS in nanotechnology, which should lead to new and effective local drug formulations for treating VVC.

Formulation, Optimization, and Evaluation of Ketoconazole Loaded Nanostructured Lipid Carrier Gel for Topical Delivery

Objective:

Ketoconazole is used in the treatment of superficial and systemic fungal infections. It acts by blocking the synthesis of ergosterol, an essential component of the fungal cell membrane. The purpose of this work was to formulate ketoconazole loaded nanostructured lipid carriers formulation for skin targeting to minimize the adverse side effects and to prolong release.

Methods:

The ketoconazole loaded nanostructured lipid carriers were optimized using 32 factorial design to evaluate the effects of process and formulation variables. The nanostructured lipid carriers were prepared by melt-dispersion ultra-sonication method. The formulations were finally incorporated into polymeric gels of Carbopol 940 for convenient application. The gels were evaluated comparatively with commercially available formulations of ketoconazole with respect to ex vivo skin permeation and deposition study on human cadaver skin.

Results:

Nanostructured lipid carriers showed average particle size, zeta potential, and percentage entrapment in the range of 125.8 ± 1.8 to 295.0 ± 3.8 nm, -13.2 ± 1.1 to -30.9 ± 2.2 mV, and 69.47 ± 2.8 to 95.49 ± 4.5, respectively. Thermal studies revealed no drug-excipient incompatibility and amorphization of ketoconazole. Ex vivo study of the gel exhibited prolonged drug release up to 12 h. In vitro drug deposition study showed that the gel formulation can avoid the systemic uptake, better accumulative uptake of the drug, and nonirritant to the skin compared to marketed formulation. Optimized formulation exhibited better antifungal activity when compared to ketoconazole loaded gel and marketed cream (Keto ® cream). Histolopathology results indicated no toxic effect on the skin.

Conclusion:

These results indicate that developed nanostructured lipid-carriers gel formulation represents a promising carrier for topical delivery of ketoconazole, having controlled drug release, and potential of skin targeting.

Development and evaluation of a film-forming system hybridized with econazole-loaded nanostructured lipid carriers for enhanced antifungal activity against dermatophytes

Treatment of skin infection by dermatophytes is still limited, and the application of conventional topical formulations (ointments, creams, etc.) cause patient discomfort due to repeated administration and low efficacy. This study describes the film-forming system (FFS) hybridized with econazole (ECO)-loaded nanostructured lipid carriers (NLC) for enhanced antifungal activity against dermatophytes. We assumed that the application of NLC could effectively increase the skin permeability of ECO, thereby suppressing the growth of dermatophytes in stratum corneum as well as in epidermis. Meanwhile, ECO-NLC hybrid FFS (ECO-NLC@FFS) could increase the adhesion of ECO-NLC to the skin and prolong the antifungal activity of ECO. First, we optimized ECO-NLC, which shows nanosized particle (199 nm), high encapsulation efficiency (92.5%), and biocompatibility. ECO-NLC@FFS formed a transparent, homogeneous, and hard-to-remove film after topical application. In vitro skin permeation and deposition studies demonstrated that ECO-NLC@FFS showed 1.5-fold higher skin permeation and 3-fold higher ECO deposition in the epidermis layer than a commercial product, which resulted from the nanosized particle and its occlusion effect. And, ex vivo and in vivo antifungal activity studies confirmed that ECO-NLC@FFS improved the skin adhesion of ECO-NLC, thereby allowing ECO to be continuously exposed to the infection sited and reducing the number of applications with a single dose. These results showed that this hybrid system could be a potential for effectively improving the efficacy of antifungal agents and the patient compliance in the treatment of dermatophytes. STATEMENT OF SIGNIFICANCE: Treatment of skin infection by dermatophytes is difficult due to the inconvenience and low efficacy of conventional topical formulations. Here, we demonstrated the potential of a film-forming system (FFS) hybridized with nanostructured lipid carriers (NLC). First, we confirmed that the enhanced skin permeability of drug was improved by NLC. In addition, the hybridization of NLC with FFS improved the skin adhesion of NLC, allowing the drug to exhibit a sustained release profile and prolong antifungal activity. Given the maximized antifungal activity, this hybrid system can be used as a potential pharmaceutical technique to improve patient convenience and achieve complete treatment of skin infection.

A Paradigm Shift in the Development of Anti-Candida Drugs

BACKGROUND

The considerable increase in the incidence of Candida infection in recent times has prompted the use of numerous antifungal agents, which has resulted in the development of resistance towards various antifungal agents. With rising Candida infections, the need for design and development of novel antifungal agents is in great demand. However, new therapeutic approaches are very essential in preventing the mortality rate and improving the patient outcome in those suffering from Candida infections.

OBJECTIVE

The present review objective is to describe the burden, types of Candidiasis, mechanism of action of antifungal agents and its resistance and the current novel approaches used to combat candidiasis.

METHODS

We have collected and analyzed 135 different peer-reviewed literature studies pertinent to candidiasis. In this review, we have compiled the major findings from these studies.

RESULTS AND CONCLUSION

The review describes the concerns related to candidiasis, its current treatment strategy, resistance mechanisms and imminent ways to tackle the problem. The review explored that natural plant extracts and essential oils could act as sources of newer therapeutic agents, however, the focus was on novel strategies, such as combinational therapy, new antibodies, utilization of photodynamic therapy and adaptive transfer primed immune cells with emphasis on the development of effective vaccination.

In Vitro Activity of Chlorhexidine Compared with Seven Antifungal Agents against 98 Fusarium Isolates Recovered from Fungal Keratitis Patients

Fungal keratitis is a common but severe eye infection in tropical and subtropical areas of the world. In regions with a temperate climate, the frequency of infection is rising in patients with contact lenses and following trauma. Early and adequate therapy is important to prevent disease progression and loss of vision. The management of Fusarium keratitis is complex, and the optimal treatment is not well defined. We investigated the in vitro activity of chlorhexidine and seven antifungal agents against a well-characterized collection of Fusarium isolates recovered from patients with Fusarium keratitis. The fungus culture collection of the Center of Expertise in Mycology Radboudumc/CWZ was searched for Fusarium isolates that were cultured from cornea scrapings, ocular biopsy specimens, eye swabs, and contact lens fluid containers from patients with suspected keratitis. The Fusarium isolates that were cultured from patients with confirmed keratitis were all identified using conventional and molecular techniques. Antifungal susceptibility testing was performed according to the EUCAST broth microdilution reference method. The antifungal agents tested included amphotericin B, voriconazole, posaconazole, miconazole, natamycin, 5-fluorocytosine, and caspofungin. In addition, the activity of chlorhexidine was determined. The fungal culture collection contained 98 Fusarium isolates of confirmed fungal keratitis cases from 83 Dutch patients and 15 Tanzanian patients. The isolates were collected between 2007 and 2017. Fusarium oxysporum (n = 24, 24.5%) was the most frequently isolated species followed by Fusarium solani sensu stricto (n = 18, 18.4%) and Fusarium petroliphilum (n = 11, 11.2%). Amphotericin B showed the most favorable in vitro inhibition of Fusarium species followed by natamycin, voriconazole, and chlorhexidine, while 5-fluorocytosine, posaconazole, miconazole, and caspofungin showed no relevant inhibiting effect. However, chlorhexidine showed fungicidal activity against 90% of F. oxysporum strains and 100% of the F. solani strains. Our study supports the clinical efficacy of chlorhexidine and therefore warrants its further clinical evaluation for primary therapy of fungal keratitis, particularly in low and middle income countries where fungal keratitis is much more frequent and, currently, antifungal eye drops are often unavailable.

Evaluation of Liposomal and Conventional Amphotericin B in Experimental Fungal Keratitis Rabbit Model

Purpose

We evaluate the efficacy of liposomal amphotericin (Fungisome) compared to conventional amphotericin (AMB) for the treatment of fungal keratitis (FK) in an experimental rabbit model.

Methods

FK was induced in 48 New Zealand White rabbits using Aspergillus flavus and Candida albicans (24 rabbits each). Rabbits were divided into four groups: 0.1% and 0.05% Fungisome-, and 0.1% AMB-treated groups, and one untreated control group. Clinical scores were recorded throughout the study while fungal burden was estimated by corneal button culture on day 19 (study endpoint).

Results

A statistically significant improvement in clinical score was seen on day 11 in the 0.1% and 0.05% Fungisome versus untreated groups (13.91 and 14.4 vs. 19.3; P < 0.001) in the A. flavus model, and on day 9 in the 0.1% Fungisome-treated versus untreated groups (12.96 vs. 14.2; P = 0.006) in the C. albicans model. At endpoint, the mean clinical scores of the untreated controls, and the 0.1% and 0.05% Fungisome-, and 0.1% AMB-treated groups were 20 ± 1.4, 5.33 ± 1.85, 9.66 ± 2.41, and 8.16 ± 1.95, respectively, in the A. flavus model and 15.85 ± 1.87, 3.08 ± 1.31, 4.21 ± 1.370, and 4.13 ± 1.38, respectively, in the C. albicans model. Conjunctival hyperemia score was higher in the 0.1% AMB- versus 0.1% Fungisome-treated groups (1.33 vs. 0.5, P = 0.452). Lowest fungal burden in both models was seen in the 0.1% Fungisome-treated groups.

Conclusions

Clinical improvement was observed with Fungisome relative to untreated controls. However, no statistically significant differences in outcomes were observed between animals treated with Fungisome and AMB. Although the results are encouraging, future studies in humans are warranted.

Translational Relevance

FK is a leading cause of corneal blindness and is on the rise especially in developing countries. Despite the availability of various antifungal agents, heterogeneous treatment outcomes are seen due to lack of a standardized treatment regimen for FK. Although the use of liposomal AMB has been substantiated by clinical evidence in systemic infections, to our knowledge there are no in vivo studies evaluating the role of topical liposomal versus conventional formulation in FK. Our study investigated the efficacy and toxicity profile of liposomal versus conventional formulation of AMB in an experimental rabbit FK model.