Novel drug delivery strategies for improving econazole antifungal action

Quality by design driven development of lipid nanoparticles for cutaneous targeting: a preliminary approach

Fungal infections are the fourth common cause of infection affecting around 50 million populations across the globe. Dermatophytes contribute to the majority of superficial fungal infections. Clotrimazole (CTZ), an imidazole derivative is widely preferred for the treatment of topical fungal infections. Conventional topical formulations enable effective penetration of CTZ into the stratum corneum, however, its low solubility results in poor dermal bioavailability, and variable drug levels limit the efficacy. The aim was to increase dermal bioavailability and sustain drug release, thereby potentially enhancing drug retention and reducing its side effects. This work evaluated the CTZ loaded solid lipid nanoparticles (SLN) consisting of precirol and polysorbate-80 developed using high pressure homogenization and optimized with QbD approach. Prior to release studies, CTZ-SLNs were characterized by different analytical techniques. The laser diffractometry and field emission scanning electron microscopy indicated that SLNs were spherical in shape with mean diameter of 450 ± 3.45 nm. DSC and XRD results revealed that the drug remained molecularly dispersed in the lipid matrix. The CTZ-SLNs showed no physicochemical instability during 6 months of storage at different temperatures. Further, the Carbopol with its pseudoplastic behavior showed a crucial role in forming homogenous and stable network for imbibing the CTZ-SLN dispersion for effective retention in skin. As examined, in-vitro drug release was sustained up to 24 h while ex-vivo skin retention and drug permeation studies showed the highest accumulation and lowest permeation with nanogel in comparison to pure drug and Candid® cream. Further, the in-vivo antifungal efficacy of nanogel suggested once-a-day application for 10 days, supported by histopathological analysis for complete eradication infection. In summary, the findings suggest, that nanogel-loaded with CTZ-SLNs has great potential for the management of fungal infections caused by Candida albicans.

Challenges and considerations in liposomal hydrogels for the treatment of infection

INTRODUCTION

Liposomal hydrogels are novel drug delivery systems that comprise preformed liposomes incorporated in hydrogels destined for mostly localized drug therapy, herewith antimicrobial therapy. The formulation benefits from versatility of liposomes as lipid-based nanocarriers that enable delivery of various antimicrobials of different lipophilicities, and secondary vehicle, hydrogel, that assures better retention time of formulation at the infection site. Especially in an era of alarming antimicrobial resistance, efficient localized antimicrobial therapy that avoids systemic exposure of antimicrobial and related side effects is crucial.

AREAS COVERED

We provide an overview of liposomal hydrogels that were developed for superior delivery of antimicrobials at different infections sites, with focus on skin and vaginal infections. The review summarizes the challenges of infection site and most common infection-causing pathogens and offers commentary on most relevant features the formulation needs to optimize to increase the therapy outcome. We discuss the impact of liposomal composition, size, and choice of polymer-forming hydrogel on antimicrobial outcome based on the literature overview and own experience in the field.

EXPERT OPINION

Liposomal hydrogels offer improved therapy outcome in localized antimicrobial therapy. By fine-tuning of liposomal as well as hydrogel properties, formulations with superior performance can be optimized targeting specific infection site.

Potential application of matrine microneedles for the treatment of atopic dermatitis in joint skin

Atopic dermatitis (AD) commonly manifests in skin areas subjected to flexion, particularly joints. This underscores the importance of dissolving microneedles (DMNs) used in AD treatment having strong skin adhesion to prevent drug delivery interruption due to patch detachment during patient activity. Moreover, matrine (MAT), a prominent active ingredient derived from the natural plant Sophora flavescens, is known for its significant efficacy in treating skin inflammation, itching, and allergic diseases. Herein, we presented MAT-loaded DMNs (MAT-DMNs) specifically tailored for joint skin application in AD treatment. MAT-DMNs can rapidly dissolve and hydrate after application, demonstrating adhesive properties on ex vivo pig skin, rat abdominal skin, and finger joint skin, thereby ensuring sustained and uninterrupted drug delivery to the skin. In vitro evaluations revealed that MAT-DMNs exhibited 24-hour first-order release profiles with cumulative penetration rates of 78.70 ± 4.24 % and 77.14 ± 6.65 % for the low-dose and high-dose groups, respectively. Furthermore, these DMNs showed excellent skin compatibility and therapeutic efficacy in AD mice models. Specifically, the skin lesion score in MAT-DMNs group was significantly lower (2.67 ± 0.40) compared to the model group (11.60 ± 1.62) and the blank DMNs group (10.80 ± 1.67). MAT-DMNs effectively alleviated AD symptoms such as itching and inflammation by reducing epidermal thickening, decreasing mast cell infiltration, and lowering the expression of Th2 cytokines (IL-4 and IL-10) and pro-inflammatory factors (IL-1β, IL-6, and TNF-α) compared to the blank DMNs group (p < 0.01). These findings suggest that MAT-DMNs hold promise for clinical AD treatment, particularly for skin diseases commonly affecting joint areas.

Nociceptive TRP channels function as molecular target for several antifungal drugs

BACKGROUND/OBJECTIVES

Topically applied antifungal agents can induce adverse effects, such as pain and irritation. The transient receptor potential (TRP) channels-TRPA1 and TRPV1-mainly expressed in sensory neurons, act as sensors for detecting irritants. This study aims to evaluate the involvement of nociceptive channels in topical antifungal-induced pain and irritation. We tested nine topical antifungals belonging five classes: isoconazole, econazole, miconazole, clotrimazole, and ketoconazole as imidazoles; liranaftate as a thiocarbamate; terbinafine as an allylamine; amorolfine as a morpholine; and butenafine as a benzylamine.

METHODS

Intracellular calcium concentrations ([Ca2+]i) and membrane currents in response to antifungals were measured to estimate channel activity using heterologously expressing cells and isolated mouse sensory neurons.

RESULTS

In mouse TRPA1-expressing cells, all the tested drugs induced an increase in [Ca2+]i, which was abrogated or reduced by a TRPA1 blocker. Although many drugs evoked the TRPA1-nonspecific [Ca2+]i response at high concentrations, responses to clotrimazole, ketoconazole, and liranaftate were TRPA1 specific and elicited current responses in TRPA1-expressing cells. In mouse TRPV1-expressing cells, clotrimazole and ketoconazole elicited [Ca2+]i and current responses. In mouse sensory neurons, liranaftate-induced increase in [Ca2+]i was abrogated by a TRPA1 blocker and Trpa1 deletion. Responses to ketoconazole were inhibited by TRPA1 and TRPV1 blockers and by the genetic deletion of either channel.

CONCLUSION

These results suggest that topical antifungal-induced pain and irritation are attributable to the activation of nociceptive TRPA1 and/or TRPV1 channel/s. Consequently, caution should be exercised in the use of topical antifungals with symptoms of pain.

Silver nanoparticles loaded with pomegranate peel extract and hyaluronic acid mediate recovery of cutaneous wounds infected with Candida albicans

Smart innovative nanocomposites based on active ingredients and metallic nanoparticles with effective wound healing and antifungal properties are efficient in overcoming the limitations of traditional therapeutic products. Open wounds provide an ideal niche for colonization by Candida albicans (C. albicans) which poses substantial global health issues owing to delayed wound healing and disordered healing mechanisms. Therefore, proficient innovative therapies that control C. albicans infection and promote wound healing are of imperative importance for the management of wounds and prevention of infection and possible complications. This study aims to design a novel nanocarrier platform based on a hydrogel loaded with silver nanoparticles (AgNPs) and doped with pomegranate peel extract (PPE) and hyaluronic acid (HA), offering an unprecedented opportunity to achieve skin repair and manage C. albicans colonization with an efficient wound healing process. Sprague-Dawley rats (n=100) were assigned to 5 groups and infected with C. albicans and distributed as follows: control positive (untreated) and four cutaneous wound-healing model groups treated topically with commercial cream and PPE-HA-AgNPs at full, 50%, and 25% concentrations for 15 days, respectively. Our findings revealed that the severity of clinical signs, C. albicans burden, and the expression of biofilm-related genes ALS1, HYR1, and PLB1 were diminished following treatment with PPE-HA-AgNPsIII. Notably, the formulated nanocomposite was very effective in extending the release of PPE-HA-AgNPs in infected wounds with retention percentages of 65.4% for PPE-HA-AgNPsIII. Topical administration of PPE-HA-AgNPsIII successfully alleviated the extensive inflammatory response and healed wounded skin via downregulation of tumor necrosis factor-alpha (TNF-α), interleukin-6 and IL-1 beta, and nitric oxide synthase (NOS) levels as shown by enzyme-linked immunosorbent (ELISA) and reverse transcription-quantitative polymerase chain reaction (RT-qPCR) assays. Interestingly, PPE-HA-AgNPsIII modulated angiogenic and wound healing markers as evidenced by the downregulation of MMP-9 and the upregulation of angiopoietin-1 (Ang-1), vascular endothelial growth factor (VEGF) (up to 10 days post-treatment), transforming growth factor-beta 1 (TGF-β1), bFGF, EGF, Ki-67, and collagen I and III with efficient wound closure capability. This was evidenced by the lessening of histopathological severity, which accelerated the healing of the infected skin wounds post-treatment with PPE-HA-AgNPs. Overall, our formulated PPE-HA-AgNPs provide an effective innovative therapeutic strategy for the treatment of cutaneous wounds infected with C. albicans with maximized wound healing efficacy, indicating their potential in clinical practice.

Nociceptive transient receptor potential ankyrin 1 (TRPA1) in sensory neurons are targets of the antifungal drug econazole

BACKGROUND

Econazole is a widely used imidazole derivative antifungal for treating skin infections. The molecular targets for its frequent adverse effects of skin irritation symptoms, such as pruritus, burning sensation, and pain, have not been clarified. Transient receptor potential (TRP) channels, non-selective cation channels, are mainly expressed in peripheral sensory neurons and serve as sensors for various irritants.

METHODS

We investigated the effect of econazole on TRP channel activation by measuring intracellular calcium concentration ([Ca2+]i) through fluorescent ratio imaging in mouse dorsal root ganglion (DRG) neurons isolated from wild-type, TRPA1(-/-) and TRPV1(-/-) mice, as well as in heterologously TRP channel-expressed cells. A cheek injection model was employed to assess econazole-induced itch and pain in vivo.

RESULTS

Econazole evoked an increase in [Ca2+]i, which was abolished by the removal of extracellular Ca2+ in mouse DRG neurons. The [Ca2+]i responses to econazole were suppressed by a TRPA1 blocker but not by a TRPV1 blocker. Attenuation of the econazole-induced [Ca2+]i responses was observed in the TRPA1(-/-) mouse DRG neurons but was not significant in the TRPV1(-/-) neurons. Econazole increased the [Ca2+]i in HEK293 cells expressing TRPA1 (TRPA1-HEK) but not in those expressing TRPV1, although at higher concentrations, it induced Ca2+ mobilization from intracellular stores in untransfected naïve HEK293 cells. Miconazole, which is a structural analog of econazole, also increased the [Ca2+]i in mouse DRG neurons and TRPA1-HEK, and its nonspecific action was larger than econazole. Fluconazole, a triazole drug failed to activate TRPA1 and TRPV1 in mouse DRG neurons and TRPA1-HEK. Econazole induced itch and pain in wild-type mice, with reduced responses in TRPA1(-/-) mice.

CONCLUSIONS

These findings suggested that the imidazole derivatives econazole and miconazole may induce skin irritation by activating nociceptive TRPA1 in the sensory neurons. Suppression of TRPA1 activation may mitigate the adverse effects of econazole.

Development of solid lipid microparticles (SLMs) containing asiatic acid for topical treatment of acne: Characterization, stability, in vitro and in vivo anti-acne assessment

Solid lipid microparticles (SLMs) represent a promising approach for drug delivery in anti-acne applications. In this study, asiatic acid-loaded SLMs (AASLMs) were prepared by melt emulsification method in conjunction with freeze-drying. Comprehensive evaluations comprised particle size, %entrapment efficiency (%EE), %labeled amount (%LA), surface morphology, stability, %release, %skin permeation, and anti-acne activity. The AASLMs exhibited an average particle size ranging from 7.46 to 38.86 µm, with %EE and %LA falling within the range of 31.56 to 100.00 and 90.43 to 95.38, respectively. The AASLMs demonstrated a spherical shape under scanning electron microscopy, and maintained stability over a 3-month period. Notably, formulations with 10 % and 15 % cetyl alcohol stabilized with poloxamer-188 (specifically F6 and F12) displayed a minimum inhibitory concentration (MIC) value of 75 mg/ml against Cutibacterium acnes. Furthermore, F12 exhibited a higher %release and %skin permeation compared to F6 over 24 h. In a single-blind clinical trial involving fifteen participants with mild-to-moderate acne, F12 showcased its potential not only in reducing porphyrin intensity and enhancing skin barriers but also in significantly improving skin hydration and brightness. However, further investigations with larger subject cohorts encompassing diverse age groups and genders are necessary to thoroughly establish the performance of the developed AASLMs.

Simplified Modular Access to Enantiopure 1,2-Aminoalcohols via Ni-Electrocatalytic Decarboxylative Arylation

Chiral aminoalcohols are omnipresent in bioactive compounds. Conventional strategies to access this motif involve multiple-step reactions to install the requisite functionalities stereoselectively using conventional polar bond analysis. This study reveals that a simple chiral oxazolidine-based carboxylic acid can be readily transformed to substituted chiral aminoalcohols with high stereochemical control by Ni-electrocatalytic decarboxylative arylation. This general, robust, and scalable coupling can be used to synthesize a variety of medicinally important compounds, avoiding protecting and functional group manipulations, thereby dramatically simplifying their preparation.

Delivery Strategies for Colchicine as a Critical Dose Drug: Reducing Toxicity and Enhancing Efficacy

Colchicine (COL), a widely used natural drug, has potent anti-inflammatory effects; however, as a narrow therapeutic index drug, its clinical application is limited by its serious gastrointestinal adverse effects, and only oral formulations are currently marketed worldwide. Recent studies have shown that transdermal, injection, and oral drug delivery are the three main delivery strategies for COL. This article elaborates on the research progress of different delivery strategies in terms of toxicity reduction and efficacy enhancement, depicting that the transdermal drug delivery route can avoid the first-pass effect and the traumatic pain associated with the oral and injection routes, respectively. Therefore, such a dosage form holds a significant promise that requires the development of further research to investigate effective COL delivery formulations. In addition, the permeation-promoting technologies utilized for transdermal drug delivery systems are briefly discussed. This article is expected to provide scientific ideas and theoretical guidance for future research and the exploration of COL delivery strategies.

Nanotechnology-based Drug Delivery of Topical Antifungal Agents

Among the various prominent fungal infections, superficial ones are widespread. A large number of antifungal agents and their formulations for topical use are commercially available. They have some pharmacokinetic limitations which cannot be retracted by conventional delivery systems. While nanoformulations composed of lipidic and polymeric nanoparticles have the potential to overcome the limitations of conventional systems. The broad spectrum category of antifungals i.e. azoles (ketoconazole, voriconazole, econazole, miconazole, etc.) nanoparticles have been designed, prepared and their pharmacokinetic and pharmacodynamic profile was established. This review briefly elaborates on the types of nano-based topical drug delivery systems and portrays their advantages for researchers in the related field to benefit the available antifungal therapeutics.

Molecular Cloning, Heterologous Expression, Purification, and Evaluation of Protein-Ligand Interactions of CYP51 of Candida krusei Azole-Resistant Fungal Strain

Due to the increasing prevalence of fungal diseases caused by fungi of the genus Candida and the development of pathogen resistance to available drugs, the need to find new effective antifungal agents has increased. Azole antifungals, which are inhibitors of sterol-14α-demethylase or CYP51, have been widely used in the treatment of fungal infections over the past two decades. Of special interest is the study of C. krusei CYP51, since this fungus exhibit resistance not only to azoles, but also to other antifungal drugs and there is no available information about the ligand-binding properties of CYP51 of this pathogen. We expressed recombinant C. krusei CYP51 in E. coli cells and obtained a highly purified protein. Application of the method of spectrophotometric titration allowed us to study the interaction of C. krusei CYP51 with various ligands. In the present work, the interaction of C. krusei CYP51 with azole inhibitors, and natural and synthesized steroid derivatives was evaluated. The obtained data indicate that the resistance of C. krusei to azoles is not due to the structural features of CYP51 of this microorganism, but rather to another mechanism. Promising ligands that demonstrated sufficiently strong binding in the micromolar range to C. krusei CYP51 were identified, including compounds 99 (Kd = 1.02 ± 0.14 µM) and Ch-4 (Kd = 6.95 ± 0.80 µM). The revealed structural features of the interaction of ligands with the active site of C. krusei CYP51 can be taken into account in the further development of new selective modulators of the activity of this enzyme.

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.

Topical caffeine-loaded nanostructured lipid carriers for enhanced treatment of cellulite: A 32 full factorial design optimization and in vivo evaluation in rats

The goal of this study was the development and evaluation of semisolid caffeine (CAF) loaded nanostructured lipid carriers (NLCs) for topical treatment of cellulite. CAF-loaded NLC formulations were prepared via high-speed homogenization followed by ultrasonication. A 32 full factorial design was employed for formulation optimization. The total lipid content (%) and the liquid lipid content per total lipids (%) were chosen as factors, whereas particle size (PS), polydispersity index (PDI), zeta potential (|ZP|) and viscosity (VIS) were selected as responses. The design suggested CAF-NLC3 as the optimum formulation consisting of a total lipid content of 15% w/w (palmitic acid and soft paraffin/isopropyl myristate, 7:3 w/w) and a surfactant content of 10% w/w (Tween 80/lecithin, 8:1.2 w/w). CAF-NLC3 revealed PS, PDI, ZP, VIS and CAF content values of 318.8 nm, 0.253, -41.1 mV, 18.0 Pa.s and 97.57%, respectively. It showed a pseudoplastic rheological behavior, acceptable pH value (5.25), good spreadability (1.12 mm2/g) and spherical shape employing transmission electron microscopy. Differential scanning calorimetry and X-ray diffraction demonstrated the amorphization of CAF in CAF-NLC3. CAF-NLC3 remained stable for 3 months at room and refrigeration conditions. A single topical application of CAF-NLC3 on shaved abdominal skins of Wistar rats revealed enhanced skin retention of CAF by 2-fold and 1.4-fold after 4 h when compared with plain CAF gel (CAF-P) and marketed CAF gel (CAF-M), respectively. Furthermore, CAF-NLC3 exhibited a superior anti-cellulite activity in comparison with CAF-P and CAF-M through elevating extracellular matrix components (collagen 1, elastin and hyaluronic acid) and stimulating the brown adipose tissue thermogenesis via up-regulating UCP1 and PPAR-γ expression. In addition, CAF-NLC3 prominently increased lipolysis through HSL activity and decreased pro-inflammatory cytokines such as ICAM-1 and VCAM-1 after 30 days of treatment on a high fat diet-induced cellulite rat model. These findings were further confirmed by histopathological examination supported by morphometric analysis. Therefore, incorporation of CAF in a semisolid NLC formulation would be a promising cosmetic approach for the topical treatment of cellulite.

The Specific Binding and Promotion Effect of Azoles on Human Aldo-Keto Reductase 7A2

Human AKR 7A2 broadly participates in the metabolism of a number of exogenous and endogenous compounds. Azoles are a class of clinically widely used antifungal drugs, which are usually metabolized by CYP 3A4, CYP2C19, and CYP1A1, etc. in vivo. The azole-protein interactions that human AKR7A2 participates in remain unreported. In this study, we investigated the effect of the representative azoles (miconazole, econazole, ketoconazole, fluconazole, itraconazole, voriconazole, and posaconazole) on the catalysis of human AKR7A2. The steady-state kinetics study showed that the catalytic efficiency of AKR7A2 enhanced in a dose-dependent manner in the presence of posaconazole, miconazole, fluconazole, and itraconazole, while it had no change in the presence of econazole, ketoconazole, and voriconazole. Biacore assays demonstrated that all seven azoles were able to specifically bind to AKR7A2, among which itraconazole, posaconazole, and voriconazole showed the strongest binding. Blind docking predicted that all azoles were apt to preferentially bind at the entrance of the substrate cavity of AKR7A2. Flexible docking showed that posaconazole, located at the region, can efficiently lower the binding energy of the substrate 2-CBA in the cavity compared to the case of no posaconazole. This study demonstrates that human AKR7A2 can interact with some azole drugs, and it also reveals that the enzyme activity can be regulated by some small molecules. These findings will enable a better understanding of azole-protein interactions.

Ethanol-Induced Aggregation of Nonpolar Nanoparticles in Water/Ethanol Mixed Solvents

The dispersity of nonpolar nanoparticles (NPs) in water/ethanol mixed solvents was studied using molecular dynamics simulations. Based on the rule of "like dissolves like," nonpolar NPs should be dispersed better in a solvent with a lower polarity. As the mole fraction of ethanol in a mixed solvent (R) increases from 0% (pure water) to 100% (pure ethanol), the polarity of the mixed solvent is indicated to decrease monotonically. However, the dispersity of nonpolar NP does not increase monotonically: it first decreases after the addition of a small fraction of ethanol (R < 8.0%) and then markedly increases as R further grows. When there is a small amount of ethanol, the ethanol molecules around aggregated NPs tend to simultaneously make contact with multiple NPs, which can increase the tendency of NP aggregation. Furthermore, with a considerable ethanol ratio, the interaction of the solvent with NPs becomes notably strong, which facilitates the dissolution of NPs. Our findings may help to better understand the mechanism of dispersion of NPs in mixed solvents and may provide a useful precipitation technology for NP production.

The Effects of Drying Techniques on Phytochemical Contents and Biological Activities on Selected Bamboo Leaves

The therapeutic potential of bamboos has acquired global attention. Nonetheless, the biological activities of the plants are rarely considered due to limited available references in Sabah, Malaysia. Furthermore, the drying technique could significantly affect the retention and degradation of nutrients in bamboos. Consequently, the current study investigated five drying methods, namely, sun, shade, microwave, oven, and freeze-drying, of the leaves of six bamboo species, Bambusa multiplex, Bambusa tuldoides, Bambusa vulgaris, Dinochloa sublaevigata, Gigantochloa levis, and Schizostachyum brachycladum. The infused bamboo leaves extracts were analysed for their total phenolic content (TPC) and total flavonoid content (TFC). The antioxidant activities of the samples were determined via the 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), and ferric reducing antioxidant power (FRAP) assays, whereas their toxicities were evaluated through the brine shrimp lethality assay (BSLA). The chemical constituents of the samples were determined using liquid chromatography−tandem mass spectrometry (LC-MS/MS). The freeze-drying method exhibited the highest phytochemical contents and antioxidant activity yield, excluding the B. vulgaris sample, in which the microwave-dried sample recorded the most antioxidant and phytochemical levels. The TPC and TFC results were within the 2.69 ± 0.01−12.59 ± 0.09 mg gallic acid equivalent (GAE)/g and 0.77 ± 0.01−2.12 ± 0.01 mg quercetin equivalent (QE)/g ranges, respectively. The DPPH and ABTS IC50 (half-maximal inhibitory concentration) were 2.92 ± 0.01−4.73 ± 0.02 and 1.89−0.01 to 3.47 ± 0.00 µg/mL, respectively, indicating high radical scavenging activities. The FRAP values differed significantly between the drying methods, within the 6.40 ± 0.12−36.65 ± 0.09 mg Trolox equivalent (TE)/g range. The phytochemical contents and antioxidant capacities exhibited a moderate correlation, revealing that the TPC and TFC were slightly responsible for the antioxidant activities. The toxicity assessment of the bamboo extracts in the current study demonstrated no toxicity against the BSLA based on the LC50 (lethal concentration 50) analysis at >1000 µg/mL. LC-MS analysis showed that alkaloid and pharmaceutical compounds influence antioxidant activities, as found in previous studies. The acquired information might aid in the development of bamboo leaves as functional food items, such as bamboo tea. They could also be investigated for their medicinal ingredients that can be used in the discovery of potential drugs.

Resistance profiles to antifungal agents in Candida albicans isolated from human oral cavities: systematic review and meta-analysis

Aim

To identify the antifungal susceptibility profile of Candida spp. isolated from the human oral cavity was assessed with meta-analyses of observational studies that collected samples from the oral cavity of human subjects.

Material and methods

Isolated Candida albicans tested by E-test®; disk diffusion test; microdilution and macrodilution; Sensititre YeastOne; and/or FungiTest. Search strategies were conducted on the MEDLINE, Embase, CINAHL, Dentistry, and Oral Sciences, Central, Scopus, and LILACS databases, and gray literature sources. Articles were initially screened by title and then their abstracts. Articles that met the conditions for inclusion were read in full, followed by data extraction. A descriptive analysis was conducted of each study, and the data were tabulated. A first meta-analysis was conducted to assess the resistance of antifungals regardless of systemic comorbidities. An additional stratified analysis was conducted by systemic comorbidity groups for the outcome “resistance” to the antifungals.

Results

When not grouping Candida albicans isolates by systemic conditions, the lowest resistance rates to the antifungals tested were observed for amphotericin B, nystatin, flucytosine, and caspofungin. In contrast, the highest resistance rates were observed for miconazole and econazole. There was a high degree of heterogeneity and low resistance in general in all analyses, except for the “several associated comorbidities” group, which had high resistance rates.

Conclusions

Clinical C. albicans isolates had low antifungal resistance.

Clinical relevance

The presence of concomitant systemic comorbidities appears to be an essential factor that should be considered when evaluating resistance to antifungals for oral isolates.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00784-022-04716-2.

Diversity of Parengyodontium spp. strains isolated from the cultural heritage environment: Phylogenetic diversity, phenotypical diversity, and occurrence

Parengyodontium album is a fungal species that frequently occurs in the cultural heritage environment. Although three subclades were initially described in the species, no study has sought to determine the occurrence of each subclade in the cultural heritage context. These subclades are easily distinguishable phylogenetically, but their morphological identification is more difficult. Eighteen strains isolated from different cultural sites and initially identified as P. album were studied phylogenetically, morphologically, and in terms of their susceptibility to econazole nitrate 0.2%, an antifungal product used as preservation treatment in cultural heritage domain. The phylogenetic study revealed that all studied strains belonged to P. album subclade 1 or P. torokii (P. album subclade 3) and none belonged to P. album subclade 2. The morphological study revealed the best characteristics to differentiate the three subclades/species, namely, the ability of the strains to grow at 32 C and 35 C on potato dextrose agar (PDA) medium and the shape of conidia. Finally, the strains displayed variable susceptibilities to econazole nitrate, with no apparent link to any particular subclade/species.

In Vitro, Ex Vivo, and In Vivo Evaluation of Nanoparticle-Based Topical Formulation Against Candida albicans Infection

Ketoconazole is commonly used in the treatment of topical fungal infections. The therapy requires frequent application for several weeks. Systemic side effects, allergic reactions, and prolonged treatment are often associated with non-compliance and therapy failure. Hence, we developed an optimized topical antifungal gel that can prolong the release of drug, reduce systemic absorption, enhance its therapeutic effect, and improve patient compliance. Ketoconazole-loaded PLGA nanoparticles were prepared by the emulsion/solvent evaporation method and were characterized with respect to colloidal properties, surface morphology, and drug entrapment efficiency. The optimized ketoconazole-loaded PLGA nanoparticles and commercially available silver nanoparticles were incorporated into a Carbopol 934P-NF gel base. This arrangement was characterized and compared with commercially available 2% ketoconazole cream to assess physical characteristics of the gel, in vitro drug release, ex vivo skin permeation and retention, and in vivo studies on Wister male albino rats. The results showed that polymeric PLGA nanoparticles were very effective in extending the release of ketoconazole in our optimized formulation. Nanoparticles were smooth, spherical in shape, and below 200 nm in size which is consistent with the data obtained from light scattering and SEM images. The ex vivo data showed that our gel formulation could strongly reduce drug permeation through the skin, and more than 60% of the drug was retained on the upper surface of the skin in contrast to 38.42% of the commercial cream. The in vivo studies showed that gel formulation could effectively treat the infection. This study demonstrates that our topical gel could be effective in sustaining the release of drug and suggests its potential use as a possible strategy to combat antifungal-resistant Candida albicans.

Simultaneous Delivery of Econazole, Terbinafine and Amorolfine with Improved Cutaneous Bioavailability: A Novel Micelle-Based Antifungal “Tri-Therapy”

Lack of accurate diagnosis and the use of formulations designed to address the poor aqueous solubility of antifungal agents, but not optimized for delivery, contribute to unsatisfactory outcomes for topical treatment of cutaneous mycoses. The objective of this study was to develop a micelle-based antifungal formulation containing econazole (ECZ), terbinafine (TBF) and amorolfine (AMF) using D-α-tocopheryl polyethylene glycol succinate (TPGS) for simultaneous cutaneous delivery of three agents with complementary mechanisms of action. The antifungal “tri-therapy” micelle-based formulation containing 0.1% ECZ, 0.1% TBF and 0.025% AMF had a drug loading 10-fold lower than the “reference” marketed formulations (Pevaryl^®, 1% ECZ; Lamisil^®, 1% TBF; Loceryl^®, 0.25% AMF). Finite dose application of the micelle-based formulation for 6 h resulted in a statistically equivalent deposition of ECZ (p > 0.05) and TBF (p > 0.05) from the 2 systems, and a 2-fold higher accumulation of AMF (p = 0.017). Antifungal concentrations above MIC₈₀ against Trichophyton rubrum were achieved in each skin layer with the “tri-therapy”, which also exhibited a preferential deposition of each antifungal agent in pilosebaceous unit (PSU)-containing biopsies as compared with PSU-free biopsies (p < 0.05). A planned clinical study will test whether these promising results translate to improved therapeutic outcomes in vivo.

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...

Topical Allopurinol-Loaded Nanostructured Lipid Carriers: A Novel Approach for Wound Healing Management

Nanostructured lipid carriers (NLC) have been widely studied as delivery systems for a variety of routes, including the skin. Their composition results in an imperfect lipid matrix, allowing increased drug encapsulation. Allopurinol (AP), a xanthine oxidase inhibitor, is characterized by low water solubility and high melting point, which has hampered its use through the topical route. In this work, AP was incorporated in a NLC formulation to enhance drug-carrier association and skin delivery as a topical approach to treat wounds. AP-NLC system was characterized in terms of size, charge, rheological behavior, and in vitro skin permeation. The in vitro cytotoxicity was evaluated using HaCaT cells. The wound healing efficacy of the AP-NLC formulation on animal skin lesions was evaluated in male Wistar rats. The AP-NLC presented a mean size of 193 ± 15 nm with a PdI of 0.240 ± 0.02, zeta potential values around −49.6 mV, and an encapsulation efficiency of 52.2%. The AP-NLC formulation presented an adequate profile to be used topically, since epidermal and dermal drug retention were achieved. No reduction in HaCaT cells viability was observed at the tested concentrations (AP < 10 μg/mL). The in vivo application of the AP-NLC formulation resulted in the regeneration of skin lesions when compared with non-treated controls.

Advanced Nano-Carriers for Anti-Tumor Drug Loading

Chemotherapy is one of the important means of tumor therapy. However, most of the anti-tumor drugs that currently used in clinic are hydrophobic non-specific drugs, which seriously affect the efficacy of drugs. With the development of nanotechnology, drug efficacy can be improved by selecting appropriate biodegradable nanocarriers for achieving the controlled release, targeting and higher bioavailability of drugs. This paper reviewed the research progress of anti-tumor drug nanoparticle carriers, which mainly summarized the materials used for anti-tumor drug nanoparticle carriers and their effects in anti-tumor drugs, as well as the targeted drug delivery methods of anti-tumor drugs based on nanocarriers.

Elastic and Ultradeformable Liposomes for Transdermal Delivery of Active Pharmaceutical Ingredients (APIs)

Administration of active pharmaceutical ingredients (APIs) through the skin, by means of topical drug delivery systems, is an advanced therapeutic approach. As the skin is the largest organ of the human body, primarily acting as a natural protective barrier against permeation of xenobiotics, specific strategies to overcome this barrier are needed. Liposomes are nanometric-sized delivery systems composed of phospholipids, which are key components of cell membranes, making liposomes well tolerated and devoid of toxicity. As their lipid compositions are similar to those of the skin, liposomes are used as topical, dermal, and transdermal delivery systems. However, permeation of the first generation of liposomes through the skin posed some limitations; thus, a second generation of liposomes has emerged, overcoming permeability problems. Various mechanisms of permeation/penetration of elastic/ultra-deformable liposomes into the skin have been proposed; however, debate continues on their extent/mechanisms of permeation/penetration. In vivo bioavailability of an API administered in the form of ultra-deformable liposomes is similar to the bioavailability achieved when the same API is administered in the form of a solution by subcutaneous or epi-cutaneous injection, which demonstrates their applicability in transdermal drug delivery.

Lipid nanovesicles for biomedical applications: 'What is in a name'?

Vesicles, generally defined as self-assembled structures formed by single or multiple concentric bilayers that surround an aqueous core, have been widely used for biomedical applications. They can either occur naturally (e.g. exosomes) or be produced artificially and range from the micrometric scale to the nanoscale. One the most well-known vesicle is the liposome, largely employed as a drug delivery nanocarrier. Liposomes have been modified along the years to improve physicochemical and biological features, resulting in long-circulating, ligand-targeted and stimuli-responsive liposomes, among others. In this process, new nomenclatures were reported in an extensive literature. In many instances, the new names suggest the emergence of a new nanocarrier, which have caused confusion as to whether the vesicles are indeed new entities or could simply be considered modified liposomes. Herein, we discussed the extensive nomenclature of vesicles based on the suffix "some" that are employed for drug delivery and composed of various types and proportions of lipids and others amphiphilic compounds. New names have most often been selected based on changes of vesicle lipid composition, but the payload, structural complexity (e.g. multicompartment) and new/improved proprieties (e.g. elasticity) have also inspired new vesicle names. Based on this discussion, we suggested a rational classification for vesicles.

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.

Development and in vitro evaluation of mucoadhesive gelatin films for the vaginal delivery of econazole

Several strategies have been explored to obtain effective econazole nitrate (ECN) concentrations at the site of application for a prolonged time. In this paper, different gelatin-based film formulations for vaginal application were investigated, containing ECN (10% w/w with respect to gelatin) as pure drug or as drug-solid dispersions (SD). For the production of SD, different polymers were evaluated: polyvinylpyrrolidone (PVP), Soluplus® (polyvinyl caprolactam-polyvinyl acetate-polyethylene glycol graft copolymer) and Gelucire® 50/13 (mixture of mono-, di- and triglycerides of fatty acids, esters of PEG 1500 and free PEG). Gelucire®-SD showed the best solubility enhancement, increasing 9.2 times the ECN solubility in pH 4.5 solution respect to pure drug; DSC and XRD analysis confirmed the crystalline form of the drug. XRD results evidenced that all gelatin-based films, containing either the drug or the SD, underwent the topotactic transformation of ECN into crystalline econazole (EC), owing to a strong interaction between the drug and the gelatin. Films containing Gelucire®-based SD displayed lower brittleness and rigidity with respect to the other samples; moreover they demonstrated good structural integrity after 24 h of incubation in the acidic solution (swelling degree of about 350%). Then, Gelucire®-SD based films were compared with the corresponding formulations cross-linked by genipin (2% w/w). The addition of genipin did not interfere with the drug-gelatin interaction. Gelucire®-SD based films showed similar release profiles to neat gelatin films, enhancing the drug release in the first 5 h and controlling the EC release over time, avoiding the use of a crosslinking additive. Finally, gelatin films containing Gelucire® solid dispersion displayed good adhesiveness and anti-Candida activity. Overall, results support the potential use of this film formulation as noncytotoxic EC delivery system for the treatment of vaginal candidiasis.

Highlights in Mesoporous Silica Nanoparticles as a Multifunctional Controlled Drug Delivery Nanoplatform for Infectious Diseases Treatment

Infectious diseases are a major global concern being responsible for high morbidity and mortality mainly due to the development and enhancement of multidrug-resistant microorganisms exposing the fragility of medicines and vaccines commonly used to these treatments. Taking into account the scarcity of effective formulation to treat infectious diseases, nanotechnology offers a vast possibility of ground-breaking platforms to design new treatment through smart nanostructures for drug delivery purposes. Among the available nanosystems, mesoporous silica nanoparticles (MSNs) stand out due their multifunctionality, biocompatibility and tunable properties make them emerging and actual nanocarriers for specific and controlled drug release. Considering the high demand for diseases prevention and treatment, this review exploits the MSNs fabrication and their behavior in biological media besides highlighting the most of strategies to explore the wide MSNs functionality as engineered, smart and effective controlled drug release nanovehicles for infectious diseases treatment. Graphical Abstract Schematic representation of multifunctional MSNs-based nanoplatforms for infectious diseases treatment.

Evolution of Nanotechnology in Delivering Drugs to Eyes, Skin and Wounds via Topical Route

The topical route is the most preferred one for administering drugs to eyes, skin and wounds for reaching enhanced efficacy and to improve patient compliance. Topical administration of drugs via conventional dosage forms such as solutions, creams and so forth to the eyes is associated with very low bioavailability (less than 5%) and hence, we cannot rely on these for delivering drugs to eyes more efficiently. An intravitreal injection is another popular drug delivery regime but is associated with complications like intravitreal hemorrhage, retinal detachment, endophthalmitis, and cataracts. The skin has a complex structure that serves as numerous physiological barriers to the entry of exogenous substances. Drug localization is an important aspect of some dermal diseases and requires directed delivery of the active substance to the diseased cells, which is challenging with current approaches. Existing therapies used for wound healing are costly, and they involve long-lasting treatments with 70% chance of recurrence of ulcers. Nanotechnology is a novel and highly potential technology for designing formulations that would improve the efficiency of delivering drugs via the topical route. This review involves a discussion about how nanotechnology-driven drug delivery systems have evolved, and their potential in overcoming the natural barriers for delivering drugs to eyes, skin and wounds.

Development of folic acid-loaded nanostructured lipid carriers for topical delivery: preparation, characterisation and ex vivo investigation

The present work is designed to achieve efficient localised skin delivery of folic acid (FA)-loaded nanostructured lipid carriers (NLCs) to infer efficient treatment of skin photoageing conditions induced via excessive exposure to ultraviolet (UV) radiation. FA NLCs were prepared by high-speed homogenisation followed by ultrasonication. The obtained NLCs revealed high encapsulation efficiencies (89.42-99.26%) with nanometric particle sizes (27.06-85.36 nm) of monodisperse distribution (PDI = 0.137-0.442), zeta potential values >|27| mV, pseudoplastic rheological behaviour, good spreadability (2.25-3.30 cm) and promoted occlusive properties throughout 48 h. Optimised NLC formulations appeared as sphere-shaped particles using transmission electron microscopy, showed improved photostability of FA and prolonged in vitro release profile best fitted to Higuchi diffusion model. Ex vivo permeation and deposition of FA, employing Wistar rat skins, depicted enhanced permeability and existence of FA in skin layers after 6 h. Based on the obtained results, FA-loaded NLC formulations demonstrate a promising modality for anti-photoageing therapy.

Ultrasound-mediated topical delivery of econazole nitrate with potential for treating Raynaud's phenomenon

The study aims to assess the ultrasound-assisted econazole nitrate (EN) permeation from topically applied formulations with potential for treating Raynaud's phenomenon. Optimization of ultrasound parameters such as the distance of the horn, application time and amplitude were performed. In vitro percutaneous absorption studies were performed using econazole formulations (F2_HPMC dispersion, F4_Lipoderm® Activemax™ Cream) across the ultrasound-treated porcine skin and were compared with the control group (skin samples without ultrasound). Histology and ATR-FTIR studies were performed on treated skin samples. A constant frequency (20 kHz) ultrasound application with 40% amplitude, 0.5 cm distance between ultrasound horn and the skin surface for 2 min was optimized. The permeation of EN was found to be higher from ultrasound-treated skin samples than the control group. Drug permeation from F2_HPMC dispersion was found to be higher as compared to the other formulations and the marketed EN cream. Histological evaluation confirmed that F2_HPMC dispersion showed no signs of toxicity. ATR-FTIR studies revealed a slight increase in the CH₂ stretching vibrations (~2920 cm^-1 and 2850 cm^-1) in ultrasound-treated skin samples as compared with the control. In conclusion, the ultrasound-assisted transdermal delivery of F2_HPMC dispersion could be further studied as a new therapy for Raynaud's phenomenon.

Silica-based nanosystems for therapeutic applications in the skin

Aging, exposure to oxidants, infectious pathogens, inflammogens, ultraviolet radiation and other environmental and genetic factors can result in the development of various skin disorders. Despite immense progress being made in dermatological treatments, many skin-associated problems still remain difficult to treat and various therapies have limitations. Progress in silica-based nanomaterials research provides an opportunity to overcome these drawbacks and improve therapies and is a promising tool for inclusion in clinical practice to treat skin diseases. This review focuses on the use of various types of silica nanoparticles with therapeutic applications in various skin disorders. These nanosystems improve treatment efficacy by maintaining or enhancing the effect of several drugs and are useful tools for nanomedicine, pharmaceutical sciences and future clinical applications.

Design and Characterization of Chitosan Nanoformulations for the Delivery of Antifungal Agents

Among different Candida species triggering vaginal candidiasis, Candida albicans is the most predominant yeast. It is commonly treated using azole drugs such as Tioconazole (TIO) and Econazole (ECO). However, their low water solubility may affect their therapeutic efficiency. Therefore, the aim of this research was to produce a novel chitosan nanocapsule based delivery system comprising of TIO or ECO and to study their suitability in vaginal application. These systems were characterized by their physicochemical properties, encapsulation efficiency, in vitro release, storage stability, cytotoxicity, and in vitro biological activity. Both nanocapsules loaded with TIO (average hydrodynamic size of 146.8 ± 0.8 nm, zeta potential of +24.7 ± 1.1 mV) or ECO (average hydrodynamic size of 127.1 ± 1.5 nm, zeta potential of +33.0 ± 1.0 mV) showed excellent association efficiency (99% for TIO and 87% for ECO). The analysis of size, polydispersity index, and zeta potential of the systems at 4, 25, and 37 °C (over a period of two months) showed the stability of the systems. Finally, the developed nanosystems presented fungicidal activity against C. albicans at non-toxic concentrations (studied on model human skin cells). The results obtained from this study are the first step in the development of a pharmaceutical dosage form suitable for the treatment of vaginal candidiasis.

Evaluation of topical econazole nitrate formulations with potential for treating Raynaud's phenomenon

The purpose of this work was to design and characterize a topical formulation of econazole nitrate (EN) with potential for treating Raynaud's phenomenon (RP). Four topical dosage forms (F1_topical solution, F2_HPMC or hydroxypropyl methylcellulose dispersion, F3_VersaBase^® cream, and F4_{_}Lipoderm^® Activemax™ Cream) containing 3% w/w EN were prepared and characterized for drug content, pH, viscosity, spreadability, drug crystallinity, stability, and in vitro permeation using Franz cells across pig ear skin, and results were compared to the 1% marketed EN cream. All four formulations had acceptable physical and visual characteristics required for topical application, with 3% w/w EN. The order of amount of drug permeated from highest to lowest was F2 (10.27%) > F4 (2.47%) > F1 (2.28%) > F3 (1.47%) > marketed formulation (0.22%). Formulation F2 showed better penetration of the drug into the stratum corneum, epidermis, and dermis layers. The drug concentration in the stratum corneum and epidermis was approximately 10-20 times higher with F2 compared to the marketed formulation. All formulations were found to be stable for up to 6 months. All four EN formulations were found to be better than the 1% marketed cream. Formulation F2_{_}HPMC dispersion could be further explored as a treatment option for RP.

Biopharmaceutical Development of a Bifonazole Multiple Emulsion for Enhanced Epidermal Delivery

Efficient topical delivery of imidazolic antifungals faces the challenge of overcoming its limited water solubility and its required long-lasting duration of treatments. In this paper, a hydrophilic multiple emulsion (ME) of Bifonazole (BFZ) is shown to maximize its skin retention, minimize its skin permeation, and maintain an acceptable level of being harmless in vivo. The formulations were pharmaceutically characterized and application properties were assessed based on viscosity measurements. Non-Newtonian pseudoplastic shear thinning with apparent thixotropy was observed, facilitating the formulation retention over the skin. The in vitro release profile with vertical diffusion cells showed a predominant square-root release kinetic suggesting an infinite dose depletion from the formulation. Ex vivo human skin permeation and penetration was additionally evaluated. Respective skin permeation was lower than values obtained with a commercial O/W formulation. The combination of amphoteric and non-ionic surfactants increased the bifonazole epidermal accumulation by a factor of twenty. This fact makes the possibility of increasing its current 24 h administration frequency more likely. Eventual alterations of skin integrity caused by the formulations were examined with epidermal histological analysis and in vivo preclinical measurements of skin elasticity and water retrograde permeation. Histological analysis demonstrated that the multiple emulsions were harmless. Additionally, modifications of in vivo skin integrity descriptors were considered as negligible.

Transdermal delivery of curcumin-loaded supramolecular hydrogels for dermatitis treatment

Curcumin (CUR) is a hydrophobic polyphenol with anti-inflammatory activity. However, its low water-solubility and poor skin permeation limited its application in the treatment of dermititis. CUR-loaded micelles were prepared using thin membrane hydration method with methoxy poly (ethylene glycol)-block-poly (ε-caprolactone) (MPEG-PCL) as carrier material. The drug loading capacity and encapsulation efficiency were 12.14 ± 0.33 and 93.57 ± 1.67%, respectively. CUR-loaded micelles increased CUR's water-solubility to 1.87 mg/mL, being 1.87 × 10⁶-folds higher than native CUR. CUR-loaded supramolecular hydrogels (CUR-H) were prepared through mixing the CUR-loaded micelles solution with α-cyclodextrin (α-CD) solution. The CUR-H presented continuous dissolution behaviour in aqueous medium for 4.5 h. The ex vivo skin permeation test and confocal fluorescence microscopy evaluation confirmed that CUR-H obviously enhanced skin deposition of CUR without drug flux from skin. In vivo experimental results confirmed that the CUR-H was more effective than dexamethasone ointments against croton oil-induced ear edema. The CUR-H composed of MPEG-PCL and α-CD is a promising formulation for skin inflammatory treatment.

Vesicular nanocarrier based treatment of skin fungal infections: Potential and emerging trends in nanoscale pharmacotherapy

Occurrence of skin fungal infections is increasing nowadays and their presence is more prominent in patients suffering from immunocompromised diseases like AIDS. Skin fungal infections are a major cause of visits by patients to dermatology clinics. Although, a large number of antifungal agents are available for treatment of skin fungal infections, but, their toxic profile and physicochemical characteristics reduce therapeutic outcome. When these antifungal agents are delivered topically using conventional formulations like creams and gels, they may cause various side effects like redness, burning, and swelling at the site of application. Therefore, various vesicular formulations (phospholipid based or non phospholipid based) have been explored by pharmaceutical scientists to treat skin fungal infections topically. Vesicular formulation explored for the purpose are liposomes, ethosomes, transfersomes, transethosomes, niosomes, spanlastics, oleic acid vesicles, and nanoparticles. These formulations show various advantages like bioavailability enhancement of bioactives, high skin permeation power, no side effects at application site, dosing frequency reduction, and sustained drug release. Therefore, in the present article, we have discussed about the utility of various vesicular nanocarrier systems to treat skin fungal infections.

Ubidecarenone-Loaded Nanostructured Lipid Carrier (UB-NLC): Percutaneous Penetration and Protective Effects Against Hydrogen Peroxide-Induced Oxidative Stress on HaCaT Cells

The objective of the investigation was to evaluate the percutaneous penetration of a ubidecarenone-loaded nanostructured lipid carrier (UB-NLC) and to illuminate the protective effects of UB-NLC for amelioration of hydrogen peroxide-induced oxidative damage on HaCaT cells. Ubidecarenone (UB) was encapsulated in a nanostructured lipid carrier (NLC), which was manufactured by homogenization. The morphological and dimensional properties of the prepared UB-NLC were studied by freeze-fracture transmission electron microscopy (FF-TEM) and photon correlation spectroscopy (PCS). Percutaneous penetration of UB-NLC was carried out by the Franz diffusion cells method. The change of cellular morphology was identified through a non-invasive time-lapse imaging system. The assessment was achieved via the evaluation of the levels of oxidative stress markers: reactive oxygen species (ROS), superoxide dismutase (SOD), glutathione peroxidase (GSH-PX), and malondialdehyde (MDA). Percutaneous penetration of UB loaded in NLC formulation was enhanced in comparison to free UB. Preincubation of HaCaT cells with UB-NLC attenuated the level of intracellular generation of ROS. Lipid peroxidation was diminished by UB-NLC via inhibition of MDA formation. Pretreatment of cells with UB-NLC reestablished the activity of cellular antioxidant enzymes (SOD and GSH-PX). On the basis of the investigation conducted, results suggest that formulating UB as NLC is advantageous for topical delivery and treatment of oxidative stress-induced human diseases.

Econazole-releasing porous space maintainers for fungal periprosthetic joint infection

While antibiotic-eluting polymethylmethacrylate space maintainers have shown efficacy in the treatment of bacterial periprosthetic joint infection and osteomyelitis, antifungal-eluting space maintainers are associated with greater limitations for treatment of fungal musculoskeletal infections including limited elution concentration and duration. In this study, we have designed a porous econazole-eluting space maintainer capable of greater inhibition of fungal growth than traditional solid space maintainers. The eluted econazole demonstrated bioactivity in a concentration-dependent manner against the most common species responsible for fungal periprosthetic joint infection as well as staphylococci. Lastly, these porous space maintainers retain compressive mechanical properties appropriate to maintain space before definitive repair of the joint or bony defect.

Ophthalmic Econazole Hydrogels for the Treatment of Fungal Keratitis

Econazole is a feasible alternative treatment in the management of fungal keratitis. Nevertheless, its low water solubility is considered the main limitation to the incorporation into ophthalmic formulations. In this work, econazole nitrate is solubilized by using cyclodextrins to achieve an optimum therapeutic concentration. Phase solubility diagrams suggest α-cyclodextrin as the most effective cyclodextrin and later the inclusion complex formed with this one was characterized in solution by 1D, 2D-NMR, and molecular modeling. Econazole-α-cyclodextrin inclusion complex was included in 2 types of ocular hydrogels: a natural polysaccharides ion-sensitive hydrogel and a hyaluronic acid hydrogel. Both of them show no ocular irritation in the hen's egg test on chorioallantoic membrane assay and a controlled econazole release over time. Permeability studies suggest that hydrogels do not modify the econazole nitrate permeability through bovine cornea in comparison with an econazole-α-cyclodextrin inclusion complex solution. Finally, ocular biopermanence studies performed using positron emission tomography show these hydrogels present a high retention time on the eye. Results suggest the developed formulations have a high potential as vehicles for the econazole topical ocular administration as fungal keratitis treatment.

The impacts of surface polarity on the solubility of nanoparticle

In order to study the dependence of water solubility and hydration behavior of nanoparticles on their surface polarity, we designed polar nanoparticles with varying surface polarity by assigning atomic partial charge to the surface of C60. The water solubility of the nanoparticle is enhanced by several orders of magnitude after the introduction of surface polarity. Nevertheless, when the atomic partial charge grows beyond a certain value (qM), the solubility continuously decreases to the level of nonpolar nanoparticle. It should be noted that such qM is comparable with atomic partial charge of a variety of functional groups. The hydration behaviors of nanoparticles were then studied to investigate the non-monotonic dependence of solubility on the surface polarity. The interaction between the polar nanoparticle and the hydration water is stronger than the nonpolar counterpart, which should facilitate the dissolution of the nanoparticles. On the other hand, the surface polarity also reduces the interaction of hydration water with the other water molecules and enhances the interaction between the nanoparticles which may hinder their dispersion. Besides, the introduction of surface polarity disturbs and even rearranges the hydration structure of nonpolar nanoparticle. Interestingly, the polar nanoparticle with less ordered hydration structure tends to have higher water solubility.