Microemulsion-based antifungal gel of luliconazole for dermatophyte infections: formulation, characterization and efficacy studies

Itraconazole and Difluorinated-Curcumin Containing Chitosan Nanoparticle Loaded Hydrogel for Amelioration of Onychomycosis

Onychomycosis is a nail infection caused by a fungus, Trichophyton mentagrophytes, that is responsible for major nail infections. The best method suited for treating such infections generally includes a topical remedy. However, conventional oral or topical formulations are associated with various limitations. Therefore, a more efficient and compatible formulation is developed in this study. The primary objective of the current study is to formulate and evaluate chitosan nanoparticle-based hydrogel for ameliorating onychomycosis. The sole purpose of this research was to increase the permeation of the lipophilic drug itraconazole and difluorinated curcumin, and its synergistic antifungal activity was also evaluated for the first time. Both in vitro and ex vivo drug release evaluations confirmed the sustained release of both drugs from the hydrogel, which is a prerequisite for treating onychomycosis. The results overall highlighted the promising activity of a synergistic approach that could be implemented for the treatment of onychomycosis. The hydrogel-based formulation serves as an effective method of delivery of drugs across the layers of the skin, resulting from its hydrating characteristics.

Development of a Luliconazole Nanoemulsion as a Prospective Ophthalmic Delivery System for the Treatment of Fungal Keratitis: In Vitro and In Vivo Evaluation

Luliconazole (LCZ), a novel imidazole drug, has broad-spectrum and potential antifungal effects, which makes it a possible cure for fungal keratitis; nevertheless, its medical use in ocular infections is hindered by its poor solubility. The purpose of this study was to design and optimize LCZ nanoemulsion (LCZ-NE) formulations using the central composite design-response surface methodology, and to investigate its potential in improving bioavailability following ocular topical administration. The LCZ-NE formulation was composed of Capryol 90, ethoxylated hydrogenated castor oil, Transcutol^® P and water. The shape of LCZ-NE was spherical and uniform, with a droplet size of 18.43 ± 0.05 nm and a low polydispersity index (0.070 ± 0.008). The results of an in vitro release of LCZ study demonstrated that the LCZ-NE released more drug than an LCZ suspension (LCZ-Susp). Increases in the inhibition zone indicated that the in vitro antifungal activity of the LCZ-NE was significantly improved. An ocular irritation evaluation in rabbits showed that the LCZ-NE had a good tolerance in rabbit eyes. Ocular pharmacokinetics analysis revealed improved bioavailability in whole eye tissues that were treated with LCZ-NE, compared with those treated with LCZ-Susp. In conclusion, the optimized LCZ-NE formulation exhibited excellent physicochemical properties, good tolerance, enhanced antifungal activity and bioavailability in eyes. This formulation would be safe, and shows promise in effectively treating ocular fungal infections.

Luliconazole topical dermal drug delivery for superficial fungal infections: Penetration hurdles and role of functional nanomaterials

Luliconazole is the first and only anti-fungal agent approved for the short-term treatment of superficial fungal infections. However, commercially available conventional topical dermal drug delivery cargo of luliconazole is associated with certain limitations like lower skin permeation and shorter skin retention of drug. Therefore, present review is an attempt to decode the penetration hurdles in luliconazole topical dermal drug delivery. Moreover, we also summarized the activity of functional nanomaterials based drug delivery systems employed by the scientific fraternity to improve luliconazole efficacy in superficial fungal infections on case-to-case basis. In addition, efforts have also been made to unbox the critically acclaimed mechanism of action of luliconazole against fungal cells. Under the framework of future prospects, we have analyzed the combination of luliconazole with isoquercetin using in-silico docking technique for offering synergistic antifungal activity. Isoquercetin exhibited a good affinity for superoxide dismutase (SOD), a fungal target owing to the formation of hydrogen bond with Glu132, Glu133, and Arg143, in addition to few hydrophobic interactions. On the other hand, luliconazole inhibited lanosterol-14α-demethylase and consequently blocked ergosterol. In addition, nanotechnology and artificial neural network (ANN) derived integrated drug delivery systems may also be explored for augmenting the luliconazole therapeutic efficacy in topical fungal infections. Synergy of ANN models along with topical nanoscaled drug delivery may help to achieve critical quality attributes (CQA) to gain commercial success.

Multipotentiality of Luliconazole against Various Fungal Strains: Novel Topical Formulations and Patent Review

BACKGROUND

Luliconazole is a broad-spectrum antifungal agent with impactful fungicidal and fungistatic activity. It has shown exceptional potency against miscellaneous fungal strains like Candida, Aspergillus, Malassezia, Fusarium species and various dermatophytes.

OBJECTIVE

Luliconazole belongs to class Ⅱ of the Biopharmaceutical Classification System with low aqueous solubility. Although it is available conventionally as 1% w/v topical cream, it has limitations of lower skin permeation and shorter skin retention. Therefore, nanoformulations based on various polymers and nanostructure carriers can be employed to overcome the impediments regarding topical delivery and efficacy of luliconazole.

METHODS

In this review, we have tried to provide insight into the literature gathered from authentic web resources and research articles regarding recent research conducted on the subject of formulation development, patents, and future research requisites of luliconazole.

RESULTS

Nanoformulations can play a fundamental role in improving topical delivery by escalating dermal localization and skin penetration. Fabricating luliconazole into nanoformulations can overcome the drawbacks and can efficiently enhance its antimycotic activity.

CONCLUSION

It has been concluded that luliconazole has exceptional potential in the treatment of various fungal infections, and therefore, it should be exploited to its maximum for its innovative application in the field of mycology.

Development, Optimization, and Evaluation of Luliconazole Nanoemulgel for the Treatment of Fungal Infection

The present study aimed to optimize luliconazole nanoemulsion using Box–Behnken statistical design, which was further incorporated into the polymeric gel of Carbopol 934. The formulation was characterized for its size, entrapment efficiency, ex vivo permeation, and mechanism of release. The size of the dispersed globules of the optimized drug-loaded nanoemulsion was found to be 17 ± 3.67 nm with a polydispersity index (PDI) less than 0.5. Although the surface charge was recorded at –9.53 ± 0.251, the stability was maintained by the polymeric matrix that prevented aggregation and coalescence of the dispersed globules. The luliconazole-nanoemulgel (LUL-NEG) was characterized for drug content analysis, viscosity, pH, and refractive index, where the results were found to be 99.06 ± 0.59%, 9.26 ± 0.08 Pa.s, 5.65 ± 0.17, and 1.31 ± 0.08, respectively. The permeation across the rat skin was found to be significantly higher with LUL-NEG when compared with LUL gel. Furthermore, the skin irritation test performed in experimental animals revealed that the blank NEG, as well as the LUL-NEG, did not produce any signs of erythema following 48 h exposure. In addition, the histopathological findings of the experimental skins reported no abnormal signs at the formulation application site. Finally, the NEG formulation was found to create a statistically significant zone of inhibition ( $P$  < 0.05) when compared to all other test groups. Overall, it could be summarized that the nanoemulgel approach of delivering luliconazole across the skin to treat skin fungal infections could be a promising strategy.

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.

Design and evaluation of microemulsion-based efinaconazole formulations for targeted treatment of onychomycosis through transungual route: Ex vivo and nail clipping studies

The onychomycosis treatment remains a big challenge for onychologist due to the shorter nail residence time of topical formulations and the lack of availability of novel formulations in markets for new generation antifungal drugs. The objective of this work was to design, develop, optimize, and evaluate microemulsion formulations for effective delivery of efinaconazole through transungual route in onychomycosis treatment. Capmul® MCM (Glyceryl Caprylate/Caprate) as oil, Labrasol® (caprylocaproyl polyoxyl-8 glycerides) as a surfactant, and Transcutol® P (diethylene glycol monoethyl ether) as co-surfactant exhibited higher solubility of efinaconazole and surfactant-cosurfactant mixture (Smix) in a ratio of 1:1 rendered higher microemulsion region in the pseudo-ternary phase diagram. The optimized microemulsion formulation containing 6%w/w oil phase, 22.5%w/w surfactant, 22.5%w/w co-surfactant, and 49%w/w demineralized water was converted into gel formulation using 1.0%w/w Carbopol® 934 P gelling agent and evaluated for stability of 6 months. The optimized microemulsion formulation globule size was less than 100 nm. The ex vivo permeation confirmed improved permeation of efinaconazole from microemulsion formulations (346.36±12.90μgcm^-2) in comparison to reference formulation without observing any lag in drug permeation through the nail plate. The in vitro antifungal study data indicated increased antifungal efficacy relative to efinaconazole topical solution against Trichophyton rubrum, Trichophyton mentagrophytes, and Candida albicans species. Further, an in vitro cell cytotoxicity study exhibited no toxic effect for any excipients used in the formulation while applied on nail cells. Hence, the efinaconazole loaded microemulsion formulations could be considered as an effective therapy in the treatment of onychomycosis.

Possibilities of the microemulsion use as indomethacin solubilizer and its effect on in vitro and ex vivo drug permeation from dermal gels in comparison with transcutol®

OBJECTIVE

Transcutol^® is a perfect solubilizer and an effective permeation enhancer of many active substances commonly used in cosmetics. Microemulsions due to the content of surfactant and co-surfactant could be also considered as chemical permeation enhancers that may support transdermal delivery of poorly water- soluble drugs. The purpose of this study was to investigate the effect of Transcutol^® and potential microemulsions on diffusion of poorly soluble indomethacin through an artificial membrane and excised rat skin.

METHODS

After drug solubilization in different enhancers, drug was dispersed in sodium alginate or carbopol gel used as dermal basis. For characterization of the microemulsions, the basic physico-chemical properties were determined. In vitro as well as ex vivo drug release was determined by vertical Franz cells.

RESULTS

Enhancing effect of the examined microemulsions was observed only in carbopol gel. There was an increase in cumulative drug amount released through synthetic membrane by 37.7-39.8% from the microemulsion formulation and 90.6% from Transcutol^® formulation within 6 h compared to the control samples. The differences between the permeation curves with or without the content of the enhancers were statistically significant (p < .05). Pearson correlation coefficients indicate a very high degree of dependence (r > 0.9) between in vitro and ex vivo drug release from all dermal vehicles used.

CONCLUSION

It can be stated that Transcutol^® is the best solubilizer and also penetration enhancer from the examined, and therefore it seems to be effective excipient/solubilizer in topical IND formulation.

Development of 20(S)-Protopanaxadiol-Loaded SNEDDS Preconcentrate Using Comprehensive Phase Diagram for the Enhanced Dissolution and Oral Bioavailability

In this study, we aimed to develop a 20(S)-protopanaxadiol (PPD)-loaded self-nanoemulsifying drug delivery system (SNEDDS) preconcentrate (PSP) using comprehensive ternary phase diagrams for enhanced solubility, physical stability, dissolution, and bioavailability. Capmul MCM C8 and Capryol 90 were selected as the oil phase owing to the high solubility of PPD in these vehicles (>15%, w/w). Novel comprehensive ternary phase diagrams composed of selected oil, surfactant, and PPD were constructed, and the solubility of PPD and particle size of vehicle was indicated on them for the effective determination of PSP. PSPs were confirmed via particle size distribution, physical stability, and scanning electron microscope (SEM) with the dispersion of water. The optimized PSP (CAPRYOL90/Kolliphor EL/PPD = 54/36/10, weight%) obtained from the six possible comprehensive ternary phase diagrams showed a uniform nanoemulsion with the particle size of 125.07 ± 12.56 nm without any PPD precipitation. The PSP showed a dissolution rate of 94.69 ± 2.51% in 60 min at pH 1.2, whereas raw PPD showed negligible dissolution. In oral pharmacokinetic studies, the PSP group showed significantly higher C_max and AUC_inf values (by 1.94- and 1.81-fold, respectively) than the raw PPD group (p < 0.05). In conclusion, the PSP formulation with outstanding solubilization, dissolution, and in-vivo oral bioavailability could be suggested using effective and comprehensive ternary phase diagrams.

Luliconazole-Loaded Thermosensitive Hydrogel as Aqueous based Nail Lacquer for the Treatment of Onychomycosis

Background:

Onychomycosis is a nail fungal infection which accounts for 50% of the nail diseases and is characterized by disfigurement and discoloration of nails. The current therapy includes oral and topical formulations both of which come with their own drawbacks. This has left a room for developing patient- compliant novel strategies which can facilitate drug delivery deeper into the nails effectively.

Objective:

The main objective of the present work was to develop and evaluate in situ gelling thermosensitive hydrogel as an aqueous nail lacquer for the treatment of onychomycosis. The idea was to enhance permeation of Luliconazole into the nail while simultaneously solubilizing it in a hydrophilic formulation.

Methods:

The sample of Luliconazole was authenticated using modern analytical techniques. The hydrogel- nail lacquer was prepared using poloxamer Pluronic F127. The formulation was evaluated in terms of drying time, viscosity, non- volatile content, pH, transition temperature, etc. In vitro study was done to check the drug release while determining release kinetics. In vitro transungual permeation study was done to check drug permeation through porcine hoof membrane. Stability studies were conducted to ensure formulation stability.

Results:

The results confirmed a stable formulation with enhanced permeation through porcine hoof membrane.

Conclusion:

The results support the potential use of in situ gelling thermo-sensitive hydrogels as a novel transungual formulation in the treatment of onychomycosis with a slight improvement in water resistance.

Novel Drug Delivery Strategies for the Treatment of Onychomycosis

Onychomycosis accounts for 50% of all nail disease cases and is commonly caused by dermatophytes. It was primarily considered a cosmetic problem but has been garnering attention lately due to its persistent nature and difficult treatment with relapses. With prolonged treatment duration and high cost involved in treating onychomycosis, several attempts have been made in overcoming the rigid nail barrier. The conventional treatment of onychomy-cosis involves oral and topical therapy. The oral antifungal agents though quite effective, are hepato-toxic and cause drug-drug interactions. Topical therapy is more patient compliant being devoid of such adverse effects but it suffers from another setback of improper nail penetration. Amorolfine and ciclopirox nail lacquers are popular market products. Since decades, efforts have been made to enhance topical delivery for efficiently treating ony-chomycosis. Mechanical, physical and chemical methods have been em-ployed. Despite all the attempts made, the nail delivery issues are far from be-ing solved. Recently, the focus has shifted to novel drug delivery systems like nanoparticles, microemulsions, polymeric films and nail lacquers for en-hanced drug permeation and localized therapy. The research around the world is exploring their potential as effective treatment options. This review intends to further explore the novel delivery strategies to treat a persistent fungal in-fection like onychomycosis.

Preparation of luliconazole nanocrystals loaded hydrogel for improvement of dissolution and antifungal activity

Superficial fungal infection in immunocompromised patients can lead to many disorders and complications. Currently, new topical treatment options are critically needed to treat these fungal infections. Luliconazole (LZL) is a topical antifungal medicine used for fungal infection treatment. The purpose of this paper was to develop a new topical luliconazole nanocrystal (LNC) incorporated hydrogel. This study suggested the potential benefits of LNC embedded in a gel as a drug delivery system for topical antifungal treatments. Preliminary experiments were therefore carried out to characterize the LNC in comparison with raw drug. Prepared gel was homogeneous for human use with about 88 percent trapping, non-irritant and safe. Nano-systems showed an overall 5 fold enhancement in solubility, 4 fold increase in dissolution velocity, higher skin retention and better antifungal activity. Drugs retained from LNC hydrogel (N-GEL) in different skin layers within 8 h were the highest, i.e. 62.17% compared to coarse suspension (41.87%), nanosuspension (49.77%), D-GEL (55.76%). In addition, LNC and N-GEL had higher ZOI (41.20 ± 0.61mm and 44.25 ± 0.57mm respectively) than LZL and D-GEL (35.98 ± 0.81mm and 36.83 ± 0.83mm respectively). Therefore, it was observed that LNC loaded hydrogel was more effective in killing the fungus. Consequently, hydrogel incorporated with LNC could be a new approach with improved activity and increased dermal delivery for drugs with poor aqueous solubility rather than coarse drug containing gel.

Microemulsion-based hydrogels for enhancing epidermal/dermal deposition of topically administered 20(S)-protopanaxadiol: in vitro and in vivo evaluation studies

BACKGROUND

20(S)-Protopanaxadiol (20S-PPD) is a fully deglycosylated ginsenoside metabolite and has potent dermal antiaging activity. However, because of its low aqueous solubility and large molecular size, a suitable formulation strategy is required to improve its solubility and skin permeability, thereby enhancing its skin deposition. Thus, we optimized microemulsion (ME)-based hydrogel (MEH) formulations for the topical delivery of 20S-PPD.

METHODS

MEs and MEHs were formulated and evaluated for their particle size distribution, morphology, drug loading capacity, and stability. Then, the deposition profiles of the selected 20S-PPD-loaded MEH formulation were studied using a hairless mouse skin model and Strat-M membrane as an artificial skin model.

RESULTS

A Carbopol-based MEH system of 20S-PPD was successfully prepared with a mean droplet size of 110 nm and narrow size distribution. The formulation was stable for 56 d, and its viscosity was high enough for its topical application. It significantly enhanced the in vitro and in vivo skin deposition of 20S-PPD with no influence on its systemic absorption in hairless mice. Notably, it was found that the Strat-M membrane provided skin deposition data well correlated to those obtained from the in vitro and in vivo mouse skin studies on 20S-PPD (correlation coefficient r 2 = 0.929‒0.947).

CONCLUSION

The MEH formulation developed in this study could serve as an effective topical delivery system for poorly soluble ginsenosides and their deglycosylated metabolites, including 20S-PPD.