Development and evaluation of novel miltefosine-polyphenol co-loaded second generation nano-transfersomes for the topical treatment of cutaneous leishmaniasis

Harnessing the power of novel drug delivery systems for effective delivery of apigenin: an updated review

Phytochemicals as dietary components are being extensively explored in order to prevent and treat a wide range of diseases. Apigenin is among the most studied flavonoids found in significant amount in fruits (oranges), vegetables (celery, parsley, onions), plant-based beverages (beer, tea, wine) and herbs (thyme, chamomile, basil, oregano) that has recently gained interest due to its promising pharmacological effects. However, the poor solubility and extended first pass metabolism of apigenin limits its clinical use. Various advantages have been demonstrated by nanocarrier-based platforms in the delivery of hydrophobic drugs like apigenin to diseased tissues. Apigenin nanoformulations have been reported to have better stability, high encapsulation efficiency, prolonged circulation time, sustained release, enhanced accumulation at targeted sites and better therapeutic efficacy. An overview of the major nanocarriers based delivery including liposomes, niosomes, solid lipid nanoparticles, micelles, dendrimers etc., is described. This review sheds insight into the therapeutic effects and advanced drug delivery strategies for the delivery of apigenin.

Evaluation of CD1a immunostaining in the diagnosis of cutaneous leishmaniasis caused by Leishmania donovani in Sri Lanka

Cutaneous leishmaniasis (CL) is a vector-borne parasitic disease, routinely diagnosed by direct light microscopy. The sensitivity of this method is dependent on the number of parasites present in the lesion. Immunoexpression of CD1a surface antigen by Leishmania amastigotes and its application as a diagnostic tool has been recently demonstrated in several species including Leishmania major, Leishmania tropica and Leishmania infantum. Leishmania donovani is the only reported species in Sri Lanka primarily causing CL and its CD1a status remains unexplored. We studied CD1a expression by amastigotes of L. donovani in skin biopsies from 116 patients with suspected CL. The biopsy sections were stained with CD1a clones O10 and MTB1 separately. Slit skin smear (SSS) results were considered the gold standard for diagnosis of CL. 103 cases were confirmed through SSS where 73 of them showed positive parasite staining for CD1a clone MTB1 with 70.9% sensitivity. Positivity was seen mostly in parasites closer to the epidermis. CD1a clone O10 failed to detect any amastigotes. Test sensitivity improved to 74.1% when the analysis was applied only to patients with low/no discernible Leishman-Donovan (LD) bodies in histology. Our findings show that CD1a clone MTB1 successfully stains amastigotes of L. donovani species and can be used as a supplementary diagnostic tool in detecting CL, especially when LD bodies are low in number. This method could be validated to detect other forms of leishmaniasis caused by L. donovani in Indian and sub-Saharan regions.

Combination Therapy and Phytochemical-Loaded Nanosytems for the Treatment of Neglected Tropical Diseases

Background: Neglected tropical diseases (NTDs), including leishmaniasis, trypanosomiasis, and schistosomiasis, impose a significant public health burden, especially in developing countries. Despite control efforts, treatment remains challenging due to drug resistance and lack of effective therapies. Objective: This study aimed to synthesize the current research on the combination therapy and phytochemical-loaded nanosystems, which have emerged as promising strategies to enhance treatment efficacy and safety. Methods/Results: In the present review, we conducted a systematic search of the literature and identified several phytochemicals that have been employed in this way, with the notable efficacy of reducing the parasite load in the liver and spleen in cases of visceral leishmaniasis, as well as lesion size in cutaneous leishmaniasis. Furthermore, they have a synergistic effect against Trypanosoma brucei rhodesiense rhodesain; reduce inflammation, parasitic load in the myocardium, cardiac hypertrophy, and IL-15 production in Chagas disease; and affect both mature and immature stages of Schistosoma mansoni, resulting in improved outcomes compared to the administration of phytochemicals alone or with conventional drugs. Moreover, the majority of the combinations studied demonstrated enhanced solubility, efficacy, and selectivity, as well as increased immune response and reduced cytotoxicity. Conclusions: These formulations appear to offer significant therapeutic benefits, although further research is required to validate their clinical efficacy in humans and their potential to improve treatment outcomes in affected populations.

Antileishmanial Activity, Toxicity and Mechanism of Action of Complexes of Sodium Usnate with Lanthanide Ions: Eu(III), Sm(III), Gd(III), Nd(III), La(III) and Tb(III)

Leishmaniases are neglected diseases with limited therapeutic options. Diffuse cutaneous leishmaniasis can occur in Brazil due to Leishmania amazonensis. This study details the antileishmanial activity and cytotoxicity of complexes of sodium usnate (SAU) with lanthanide ions ([LnL3 (H2O)x] (Ln = La(III), Nd(III), Gd(III), Tb(III), Eu(III) and Sm(III); L = SAU). All lanthanide complexes were highly active and more potent than SAU against L. amazonensis promastigotes and intracellular amastigotes (Pro: IC50 < 1.50 μM; Ama: IC50 < 7.52 μM). EuL3·3H2O and NdL3·3H2O were the most selective and effective on intracellular amastigotes, with a selectivity index of approximately 7.0. In silico predictions showed no evidence of mutagenicity, tumorigenicity or irritation for all complexes. Treatment with EuL3·3H2O triggered NO release even at the lowest concentration, indicating NO production as a mechanism of action against the parasite. Incubating promastigotes with the lanthanide complexes, particularly with SmL3·4H2O and GdL3·3H2O, led to a change in the mitochondrial membrane potential, indicating the ability of these complexes to target this essential organelle. The same complexes caused cell death through cell membrane disruption, but their relationship with early or late apoptotic processes remains unclear. Thus, the inclusion of lanthanide ions in SAU improves selectivity with a promising mechanism of action targeting the mitochondria.

Pro-Apoptotic Activity of Epi-Obtusane against Cervical Cancer: Nano Formulation, In Silico Molecular Docking, and Pharmacological Network Analysis

Cancer is a major disease that threatens human health all over the world. Intervention and prevention in premalignant processes are successful ways to prevent cancer from striking. On the other hand, the marine ecosystem is a treasure storehouse of promising bioactive metabolites. The use of such marine products can be optimized by selecting a suitable nanocarrier. Therefore, epi-obtusane, previously isolated from Aplysia oculifera, was investigated for its potential anticancer effects toward cervical cancer through a series of in vitro assays in HeLa cells using the MTT assay method. Additionally, the sesquiterpene was encapsulated within a liposomal formulation (size = 130.8 ± 50.3, PDI = 0.462, zeta potential -12.3 ± 2.3), and the antiproliferative potential of epi-obtusane was investigated against the human cervical cancer cell line HeLa before and after encapsulation with liposomes. Epi-obtusane exhibited a potent effect against the HeLa cell line, while the formulated molecule with liposomes increased the in vitro antiproliferative activity. Additionally, cell cycle arrest analysis, as well as the apoptosis assay, performed via FITC-Annexin-V/propidium iodide double staining (flow cytofluorimetry), were carried out. The pharmacological network enabled us to deliver further insights into the mechanism of epi-obtusane, suggesting that STAT3 might be targeted by the compound. Moreover, molecular docking showed a comparable binding score of the isolated compound towards the STAT3 SH2 domain. The targets possess an anticancer effect through the endometrial cancer pathway, regulation of DNA templated transcription, and nitric oxide synthase, as mentioned by the KEGG and ShinyGo 7.1 databases.

Nitazoxanide and quercetin co-loaded nanotransfersomal gel for topical treatment of cutaneous leishmaniasis with macrophage targeting and enhanced anti-leishmanial effect

Purpose

Anti-leishmanial medications administered by oral and parenteral routes are less effective for treatment of cutaneous leishmaniasis (CL) and cause toxicity, hence targeted drug delivery is an efficient way to improve drug availability for CL with reduced toxicity. This study aimed to develop, characterize and evaluate nitazoxanide and quercetin co-loaded nanotransfersomal gel (NTZ-QUR-NTG) for the treatment of CL.

Methods

NTZ-QUR-NT were prepared by thin film hydration method and were statistically optimized using Box-Behnken design. To ease the topical delivery and enhance the retention time, the NTZ-QUR-NT were dispersed in 2 % chitosan gel. Moreover, in-vitro drug release, ex-vivo permeation, macrophage uptake, cytotoxicity and anti-leishmanial assays were performed.

Results

The optimized formulation indicated mean particle size 210 nm, poly dispersity index (PDI) 0.16, zeta potential (ZP) -15.1 mV and entrapment efficiency (EE) of NTZ and QUR was 88 % and 85 %, respectively. NTZ-QUR-NT and NTZ-QUR-NTG showed sustained release of the incorporated drugs as compared to the drug dispersions. Skin permeation of NTZ and QUR in NTZ-QUR-NTG was 4 times higher in comparison to the plain gels. The NTZ-QUR-NT cell internalization was almost 10-folds higher than NTZ-QUR dispersion. The cytotoxicity potential (CC50) of NTZ-QUR-NT (71.95 ± 3.32 μg/mL) was reduced as compared to NTZ-QUR dispersion (49.77 ± 2.15 μg/mL. A synergistic interaction was found between NTZ and QUR. Moreover, in-vitro anti-leishmanial assay presented a lower IC50 value of NTZ-QUR-NT as compared to NTZ-QUR dispersion. Additionally, a significantly reduced lesion size was observed in NTZ-QUR-NTG treated BALB/c mice, indicating its antileishmanial potential.

Conclusion

It can be concluded that nanotransfersomal gel has the capability to retain and permeate the incorporated drugs through stratum corneum and induce synergetic anti-leishmanial effect of NTZ and QUR against cutaneous leishmaniasis.

L-Cysteine-Modified Transfersomes for Enhanced Epidermal Delivery of Podophyllotoxin

The purpose of this study was to evaluate L-cysteine-modified transfersomes as the topical carrier for enhanced epidermal delivery of podophyllotoxin (POD). L-cysteine-deoxycholic acid (LC-DCA) conjugate was synthesized via an amidation reaction. POD-loaded L-cysteine-modified transfersomes (POD-LCTs) were prepared via a thin membrane dispersion method and characterized for their particle size, zeta potential, morphology, X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and in vitro release. Subsequently, in vitro skin permeation and retention, fluorescence distribution in the skin, hematoxylin-eosin staining and in vivo skin irritation were studied. The POD-LCTs formed spherical shapes with a particle size of 172.5 ± 67.2 nm and a zeta potential of -31.3 ± 6.7 mV. Compared with the POD-Ts, the POD-LCTs provided significantly lower drug penetration through the porcine ear skin and significantly increased the skin retention (p < 0.05). Meaningfully, unlike the extensive distribution of the POD-loaded transfersomes (POD-Ts) throughout the skin tissue, the POD-LCTs were mainly located in the epidermis. Moreover, the POD-LCTs did not induce skin irritation. Therefore, the POD-LCTs provided an enhanced epidermal delivery and might be a promising carrier for the topical delivery of POD.

Silver(I) and Copper(II) 1,10-Phenanthroline-5,6-dione Complexes as Promising Antivirulence Strategy against Leishmania: Focus on Gp63 (Leishmanolysin)

Leishmaniasis, caused by protozoa of the genus Leishmania, encompasses a group of neglected diseases with diverse clinical and epidemiological manifestations that can be fatal if not adequately and promptly managed/treated. The current chemotherapy options for this disease are expensive, require invasive administration and often lead to severe side effects. In this regard, our research group has previously reported the potent anti-Leishmania activity of two coordination compounds (complexes) derived from 1,10-phenanthroline-5,6-dione (phendione): [Cu(phendione)₃].(ClO₄)₂.4H₂O and [Ag(phendione)₂].ClO₄. The present study aimed to evaluate the effects of these complexes on leishmanolysin (gp63), a virulence factor produced by all Leishmania species that plays multiple functions and is recognized as a potential target for antiparasitic drugs. The results showed that both Ag-phendione (-74.82 kcal/mol) and Cu-phendione (-68.16 kcal/mol) were capable of interacting with the amino acids comprising the active site of the gp63 protein, exhibiting more favorable interaction energies compared to phendione alone (-39.75 kcal/mol) or 1,10-phenanthroline (-45.83 kcal/mol; a classical gp63 inhibitor) as judged by molecular docking assay. The analysis of kinetic parameters using the fluorogenic substrate Z-Phe-Arg-AMC indicated V_max and apparent K_m values of 0.064 µM/s and 14.18 µM, respectively, for the released gp63. The effects of both complexes on gp63 proteolytic activity were consistent with the in silico assay, where Ag-phendione exhibited the highest gp63 inhibition capacity against gp63, with an IC₅₀ value of 2.16 µM and the lowest inhibitory constant value (K_i = 5.13 µM), followed by Cu-phendione (IC₅₀ = 163 µM and K_i = 27.05 µM). Notably, pretreatment of live L. amazonensis promastigotes with the complexes resulted in a significant reduction in the expression of gp63 protein, including the isoforms located on the parasite cell surface. Both complexes markedly decreased the in vitro association indexes between L. amazonensis promastigotes and THP-1 human macrophages; however, this effect was reversed by the addition of soluble gp63 molecules to the interaction medium. Collectively, our findings highlight the potential use of these potent complexes in antivirulence therapy against Leishmania, offering new insights for the development of effective treatments for leishmaniasis.

A Systematic Review of Drug-Carrying Nanosystems Used in the Treatment of Leishmaniasis

Leishmaniasis is an infectious disease responsible for a huge rate of morbidity and mortality in humans. Chemotherapy consists of the use of pentavalent antimonial, amphotericin B, pentamidine, miltefosine, and paromomycin. However, these drugs are associated with some drawbacks such as high toxicity, administration by parenteral route, and most seriously the resistance of some strains of the parasite to them. Several strategies have been used to increase the therapeutic index and reduce the toxic effects of these drugs. Among them, the use of nanosystems that have great potential as a site-specific drug delivery system stands out. This review aims to compile results from studies that were carried out using first- and second-line antileishmanial drug-carrying nanosystems. The articles referred to here were published between 2011 and 2021. This study shows the promise of effective applicability of drug-carrying nanosystems in the field of antileishmanial therapeutics, with the perspective of providing better patient adherence to treatment, increased therapeutic efficacy, reduced toxicity of conventional drugs, as well as the potential to efficiently improve the treatment of leishmaniasis.

The novel treatments based on tissue engineering, cell therapy and nanotechnology for cutaneous leishmaniasis

Cutaneous leishmaniasis (CL) is a global public health issue. Conventional treatments have substantial costs, side effects, and parasite resistance. Due to easy application and inexpensive cost, topical treatment is the optimal approach for CL. It could be used alone or with systemic treatments. Electrospun fibers as drug release systems in treating skin lesions have various advantages such as adjustable drug release rate, maintaining appropriate humidity and temperature, gas exchange, plasticity at the lesion site, similarity with the skin extracellular matrix (ECM) and drug delivery with high efficiency. Hydrogels are valuable scaffolds in the treatment of skin lesions. The important features of hydrogels include preserving unstable drugs from degradation, absorption of wound secretions, high biocompatibility, improving the re-epithelialization of the wound and preventing the formation of scars. One of the issues in local drug delivery systems for the skin is the low permeability of drugs in the skin. Polymeric scaffolds that are designed as microneedle patches can penetrate the skin and overcome this challenge. Also, drug delivery using nanocarriers increases the effectiveness of drugs in lower and more tolerable doses and reduces the toxicity of drugs. The application of cell therapy in the treatment of parasitic and infectious diseases has been widely investigated. The complexity of leishmaniasis treatment requires identifying new treatment options like cell therapy to overcome the disease. Topics investigated in this study include drug delivery systems based on tissue engineering scaffolds, nanotechnology and cell therapy-based studies to reduce the complications of CL.

In Vitro and Ex Vivo Evaluation of Fluocinolone Acetonide-Acitretin-Coloaded Nanostructured Lipid Carriers for Topical Treatment of Psoriasis

Psoriasis is chronic autoimmune disease that affects 2-5% of the global population. Fluocinolone acetonide (FLU) and acitretin (ACT) are widely used antipsoriatic drugs that belong to BCS classes II and IV, respectively. FLU exhibits side effects, such as skin irritation and a burning sensation. ACT also shows adverse effects, such as gingivitis, teratogenic effects and xerophthalmia. In the present study, topical nanostructured lipid carriers (NLCs) were fabricated to reduce the side effects and enhance the therapeutic efficacy. FLU-ACT-coloaded NLCs were prepared by the modified microemulsion method and optimized by the Box-Behnken model of Design Expert® version 12. The optimization was based on the particle size (PS), zeta potential (ZP) and percentage of encapsulation efficiency (%EE). The physicochemical analyses were performed by TEM, FTIR, XRD and DSC to assess the morphology, chemical interactions between excipients, crystallinity and thermal behavior of the optimized FLU-ACT-coloaded NLCs. The FLU-ACT-coloaded NLCs were successfully loaded into gel and characterized appropriately. The dialysis bag method and Franz diffusion cells were used for the in vitro release and ex vivo permeation studies, respectively. The optimized FLU-ACT-coloaded NLCs had the desired particle size of 288.2 ± 2.3 nm, ZP of -34.2 ± 1.0 mV and %EE values of 81.6 ± 1.1% for ACT and 75 ± 1.3% for FLU. The TEM results confirmed the spherical morphology, while the FTIR results showed the absence of chemical interactions of any type among the ingredients of the FLU-ACT-coloaded NLCs. The XRD and DSC analyses confirmed the amorphous nature and thermal behavior. The in vitro study showed the sustained release of the FLU and ACT from the optimized FLU-ACT-coloaded NLCs and FLU-ACT-coloaded NLC gel compared with the FLU-ACT suspension and conventional gel. The ex vivo study confirmed the minimal permeation of both drugs from the FLU-ACT-coloaded NLC gel.

Macrophage targeting of nitazoxanide-loaded transethosomal gel in cutaneous leishmaniasis

Topical delivery is preferable over systemic delivery for cutaneous leishmaniasis, because of its easy administration, reduced systemic adverse effects and low cost. Nitazoxanide (NTZ) has broad-spectrum activity against various parasites and has the potential to avoid drug resistance developed by enzymatic mutations. NTZ oral formulation is associated with severe dyspepsia and stomach pain. Herein, NTZ-transethosomes (NTZ-TES) were prepared and loaded into chitosan gel (NTZ-TEG) for topical delivery. NTZ-TES were prepared by the thin-film hydration method and optimized statistically via the Box-Behnken method. The optimized formulation indicated excellent particle size (176 nm), polydispersity index (0.093), zeta potential (-26.4 mV) and entrapment efficiency (86%). The transmission electron microscopy analysis showed spherical-sized particles and Fourier-transform infrared spectroscopy analysis indicated no interaction among the excipients. Similarly, NTZ-TEG showed optimal pH, desirable viscosity and good spreadability. NTZ-TES and NTZ-TEG showed prolonged release behaviour and higher skin penetration and deposition in the epidermal/dermal layer of skin in comparison with the NTZ-dispersion. Moreover, NTZ-TES showed higher percentage inhibition, lower half-maximal inhibitory concentration (IC₅₀) against promastigotes and higher macrophage uptake. Additionally, skin irritation and histopathology studies indicated the safe and non-irritant behaviour of the NTZ-TEG. The obtained findings suggested the enhanced skin permeation and improved anti-leishmanial effect of NTZ when administered as NTZ-TEG.

Macrophage targeting of nitazoxanide-loaded transethosomal gel in cutaneous leishmaniasis

Topical delivery is preferable over systemic delivery for cutaneous leishmaniasis, because of its easy administration, reduced systemic adverse effects and low cost. Nitazoxanide (NTZ) has broad-spectrum activity against various parasites and has the potential to avoid drug resistance developed by enzymatic mutations. NTZ oral formulation is associated with severe dyspepsia and stomach pain. Herein, NTZ-transethosomes (NTZ-TES) were prepared and loaded into chitosan gel (NTZ-TEG) for topical delivery. NTZ-TES were prepared by the thin-film hydration method and optimized statistically via the Box-Behnken method. The optimized formulation indicated excellent particle size (176 nm), polydispersity index (0.093), zeta potential (-26.4 mV) and entrapment efficiency (86%). The transmission electron microscopy analysis showed spherical-sized particles and Fourier-transform infrared spectroscopy analysis indicated no interaction among the excipients. Similarly, NTZ-TEG showed optimal pH, desirable viscosity and good spreadability. NTZ-TES and NTZ-TEG showed prolonged release behaviour and higher skin penetration and deposition in the epidermal/dermal layer of skin in comparison with the NTZ-dispersion. Moreover, NTZ-TES showed higher percentage inhibition, lower half-maximal inhibitory concentration (IC₅₀) against promastigotes and higher macrophage uptake. Additionally, skin irritation and histopathology studies indicated the safe and non-irritant behaviour of the NTZ-TEG. The obtained findings suggested the enhanced skin permeation and improved anti-leishmanial effect of NTZ when administered as NTZ-TEG.

Macrophage targeting of nitazoxanide-loaded transethosomal gel in cutaneous leishmaniasis

Topical delivery is preferable over systemic delivery for cutaneous leishmaniasis, because of its easy administration, reduced systemic adverse effects and low cost. Nitazoxanide (NTZ) has broad-spectrum activity against various parasites and has the potential to avoid drug resistance developed by enzymatic mutations. NTZ oral formulation is associated with severe dyspepsia and stomach pain. Herein, NTZ-transethosomes (NTZ-TES) were prepared and loaded into chitosan gel (NTZ-TEG) for topical delivery. NTZ-TES were prepared by the thin-film hydration method and optimized statistically via the Box-Behnken method. The optimized formulation indicated excellent particle size (176 nm), polydispersity index (0.093), zeta potential (-26.4 mV) and entrapment efficiency (86%). The transmission electron microscopy analysis showed spherical-sized particles and Fourier-transform infrared spectroscopy analysis indicated no interaction among the excipients. Similarly, NTZ-TEG showed optimal pH, desirable viscosity and good spreadability. NTZ-TES and NTZ-TEG showed prolonged release behaviour and higher skin penetration and deposition in the epidermal/dermal layer of skin in comparison with the NTZ-dispersion. Moreover, NTZ-TES showed higher percentage inhibition, lower half-maximal inhibitory concentration (IC₅₀) against promastigotes and higher macrophage uptake. Additionally, skin irritation and histopathology studies indicated the safe and non-irritant behaviour of the NTZ-TEG. The obtained findings suggested the enhanced skin permeation and improved anti-leishmanial effect of NTZ when administered as NTZ-TEG.

Antileishmanial Agents Co-loaded in Transfersomes with Enhanced Macrophage Uptake and Reduced Toxicity

The prime objective of this study was to develop amphotericin B (AMB) and rifampicin (RIF) co-loaded transfersomal gel (AMB-RIF co-loaded TFG) for effective treatment of cutaneous leishmaniasis (CL). AMB-RIF co-loaded TF was prepared by the thin-film hydration method and was optimized based on particle size, polydispersity index (PDI), zeta potential, entrapment efficiency (%EE), and deformability index. Similarly, AMB-RIF co-loaded TFG was characterized in terms of rheology, spread ability, and pH. In vitro, ex vivo, and in vivo assays were performed to evaluate AMB-RIF co-loaded TF as a potential treatment option for CL. The optimized formulation had vesicles in nanosize range (167 nm) with suitable PDI (0.106), zeta potential (- 19.05 mV), and excellent %EE of RIF (66%) and AMB (85%). Moreover, it had appropriate deformability index (0.952). Additionally, AMB-RIF co-loaded TFG demonstrated suitable rheological behavior for topical application. AMB-RIF co-loaded TF and AMB-RIF co-loaded TFG showed sustained release of the incorporated drugs as compared to AMB-RIF suspension. Furthermore, RIF permeation from AMB-RIF co-loaded TF and AMB-RIF co-loaded TFG was enhanced fivefold and threefold, whereas AMB permeation was enhanced by eightfold and 6.6-fold, respectively. The significantly different IC₅₀, higher CC₅₀, and FIC₅₀ (p < 0.5) showed synergistic antileishmanial potential of AMB-RIF co-loaded TF. Likewise, reduced lesion size and parasitic burden in AMB-RIF co-loaded TF-treated mouse group further established the antileishmanial effect of the optimized formulation. Besides, AMB-RIF co-loaded TFG showed a better safety profile. This study concluded that TFG may be a suitable carrier for co-delivery of AMB-RIF when administered topically for the treatment of CL.

Models for cytotoxicity screening of antileishmanial drugs: what has been done so far?

A growing number of studies have demonstrated the in vitro potential of an impressive number of antileishmanial candidates in the past years. However, the lack of uniformity regarding the choice of cell types for cytotoxicity assays may lead to uncomparable and inconclusive data. In vitro assays relying solely on non-phagocytic cell models may not represent a realistic result as the effect of an antileishmanial agent should ideally be presented based on its cytotoxicity profile against reticuloendothelial system cells. In the present review, we have assembled studies published in the scientific literature from 2015 to 2021 that explored leishmanicidal candidates, emphasising the main host cell models used for cytotoxicity assays. The pros and cons of different host cell types as well as primary cells and cell lines are discussed in order to draw attention to the need to establish standardised protocols for preclinical testing when assessing new antileishmanial candidates.

Triple-combination therapy for cutaneous leishmaniasis using detergent-free, hyaluronate-coated elastic nanovesicles

Aim: To develop and evaluate detergent-free, triple-drug-loaded, hyaluronate-coated elastic nanovesicles (H-ENVs) for the topical treatment of cutaneous leishmaniasis. Materials & methods: H-ENVs were developed and evaluated for vesicle size, entrapment efficiency, skin permeation and antileishmanial potential. Results: A 15.7 and 28.6% decrease in the cytotoxicity of paromomycin and amphotericin B, respectively, was observed in detergent-free ENVs compared with conventional ENVs. H-ENVs improved the efficacy of paromomycin against promastigote and amastigote models of leishmaniasis by 4- and 7.5-fold, respectively. In vivo investigation of H-ENVs demonstrated efficient topical management of cutaneous leishmaniasis. Conclusion: The results indicate the potential of H-ENVs as a safe topical treatment choice for cutaneous leishmaniasis.

Nanomedicine in leishmaniasis: A promising tool for diagnosis, treatment and prevention of disease - An update overview

Leishmaniasis is a neglected tropical disease that has a wide spectrum of clinical manifestations, ranging from visceral to cutaneous, with millions of new cases and thousands of deaths notified every year. The severity of the disease and its various clinical forms are determined by the species of the causative agent, Leishmania, as well as the host's immune response. Major challenges still exist in the diagnosis and treatment of leishmaniasis, and there is no vaccine available to prevent this disease in humans. Nanotechnology has emerged as a promising tool in a variety of fields. In this review, we highlight the main and most recent advances in nanomedicine to improve the diagnosis and treatment, as well as for the development of vaccines, for leishmaniasis. Nanomaterials are nanometric in size and can be produced by a variety of materials, including lipids, polymers, ceramics, and metals, with varying structures and morphologies. Nanotechnology can be used as biosensors to detect antibodies or antigens, thus improving the sensitivity and specificity of such immunological and molecular diagnostic tests. While in treatment, nanomaterials can act as drug carriers or, be used directly, to reduce any toxic effects of drug compounds to the host and to be more selective towards the parasite. Furthermore, preclinical studies show that different nanomaterials can carry different Leishmania antigens, or even act as adjuvants to improve a Th1 immune response in an attempt to produce an effective vaccine.

Transfersomes: a Revolutionary Nanosystem for Efficient Transdermal Drug Delivery

Transdermal delivery system has gained significance in drug delivery owing to its advantages over the conventional delivery systems. However, the barriers of stratum corneum along with skin irritation are its major limitations. Various physical and chemical techniques have been employed to alleviate these impediments. Among all these, transfersomes have shown potential for overcoming the associated limitations and successfully delivering therapeutic agents into systemic circulation. These amphipathic vesicles are composed of phospholipids and edge activators. Along with providing elasticity, edge activator also affects the vesicular size and entrapment efficiency of transfersomes. The mechanism behind the enhanced permeation of transfersomes through the skin involves their deformability and osmotic gradient across the application site. Permeation enhancers can further enhance their permeability. Biocompatibility; capacity for carrying hydrophilic, lipophilic as well as high molecular weight therapeutics; deformability; lesser toxicity; enhanced permeability; and scalability along with potential for surface modification, active targeting, and controlled release render them ideal designs for efficient drug delivery. The current review provides a brief account of the discovery, advantages, composition, synthesis, comparison with other cutaneous nano-drug delivery systems, applications, and recent developments in this area.

Surfactant free synthesis of cationic nano-vesicles: A safe triple drug loaded vehicle for the topical treatment of cutaneous leishmaniasis

The basic aim of the study was to develop and evaluate the triple drug loaded cationic nano-vesicles (cNVs), where miltefosine was used as a replacement of surfactant (apart from its anti-leishmanial role), in addition to meglumine antimoniate (MAM) and imiquimod (Imq), as a combination therapy for the topical treatment of cutaneous leishmaniasis (CL). The optimized formulation was nano-sized (86.2±2.7nm) with high entrapment efficiency (63.8±2.1% (MAM) and 81.4±2.3% (Imq)). In-vivo skin irritation assay showed reduced irritation potential and a decrease in the cytotoxicity of cNVs as compared to conventional NVs (having sodium deoxycholate as a surfactant). A synergistic interaction between drugs was observed against intracellular amastigotes, whereas the in-vivo antileishmanial study presented a significant reduction in the parasitic burden. The results suggested the potential of surfactant free, triple drug loaded cNVs as an efficient vehicle for the safe topical treatment of CL.

Transfersomes as alternative topical nanodosage forms for the treatment of skin disorders

Topical drug delivery is a promising approach to treat different skin disorders. However, it remains a challenge mainly due to the nature and rigidity of the nanosystems, which limit deep skin penetration, and the unsuccessful demonstration of clinical benefits; greater penetration by itself, does not ensure pharmacological success. In this context, transfersomes have appeared as promising nanosystems; deformability, their unique characteristic, allows them to pass through the epidermal microenvironment, improving the skin drug delivery. This review focuses on the comparison of transfersomes with other nanosystems (e.g., liposomes), discusses recent therapeutic applications for the topical treatment of different skin disorders and highlights the need for further studies to demonstrate significant clinical benefits of transfersomes compared with conventional therapies.

Lipid Nanoparticulate Drug Delivery Systems: Recent Advances in the Treatment of Skin Disorders

The multifunctional role of the human skin is well known. It acts as a sensory and immune organ that protects the human body from harmful environmental impacts such as chemical, mechanical, and physical threats, reduces UV radiation effects, prevents moisture loss, and helps thermoregulation. In this regard, skin disorders related to skin integrity require adequate treatment. Lipid nanoparticles (LN) are recognized as promising drug delivery systems (DDS) in treating skin disorders. Solid lipid nanoparticles (SLN) together with nanostructured lipid carriers (NLC) exhibit excellent tolerability as these are produced from physiological and biodegradable lipids. Moreover, LN applied to the skin can improve stability, drug targeting, occlusion, penetration enhancement, and increased skin hydration compared with other drug nanocarriers. Furthermore, the features of LN can be enhanced by inclusion in suitable bases such as creams, ointments, gels (i.e., hydrogel, emulgel, bigel), lotions, etc. This review focuses on recent developments in lipid nanoparticle systems and their application to treating skin diseases. We point out and consider the reasons for their creation, pay attention to their advantages and disadvantages, list the main production techniques for obtaining them, and examine the place assigned to them in solving the problems caused by skin disorders.

An appraisal of the scientific current situation and new perspectives in the treatment of cutaneous leishmaniasis

Leishmaniasis is a Neglected Tropical Diseases caused by protozoan parasites of the genus Leishmania. It is a major health problem in many tropical and subtropical regions of the world and can produce three different clinical manifestations, among which cutaneous leishmaniasis has a higher incidence in the world than the other clinical forms. There are no recognized and reliable means of chemoprophylaxis or vaccination against infections with different forms of leishmaniasis. In addition, chemotherapy, unfortunately, remains, in many respects, unsatisfactory. Therefore, there is a continuing and urgent need for new therapies against leishmaniasis that are safe and effective in inducing a long-term cure. This review summarizes the latest advances in currently available treatments and improvements in the development of drug administration. In addition, an analysis of the in vivo assays was performed and the challenges facing promising strategies to treat CL are discussed. The treatment of leishmaniasis will most likely evolve into an approach that uses multiple therapies simultaneously to reduce the possibility of developing drug resistance. There is a continuous effort to discover new drugs to improve the treatment of leishmaniasis, but this is mainly at the level of individual researchers. Undoubtedly, more funding is needed in this area, as well as greater participation of the pharmaceutical industry to focus efforts on the development of chemotherapeutic agents and vaccines for this and other neglected tropical diseases.

Nanotechnology based solutions for anti-leishmanial impediments: a detailed insight

As a neglected tropical disease, Leishmaniasis is significantly instigating morbidity and mortality across the globe. Its clinical spectrum varies from ulcerative cutaneous lesions to systemic immersion causing hyperthermic hepato-splenomegaly. Curbing leishmanial parasite is toughly attributable to the myriad obstacles in existing chemotherapy and immunization. Since the 1990s, extensive research has been conducted for ameliorating disease prognosis, by resolving certain obstacles of conventional therapeutics viz. poor efficacy, systemic toxicity, inadequate drug accumulation inside the macrophage, scarce antigenic presentation to body's immune cells, protracted length and cost of the treatment. Mentioned hurdles can be restricted by designing nano-drug delivery system (nano-DDS) of extant anti-leishmanials, phyto-nano-DDS, surface modified-mannosylated and thiolated nano-DDS. Likewise, antigen delivery with co-transportation of suitable adjuvants would be achievable through nano-vaccines. In the past decade, researchers have engineered nano-DDS to improve the safety profile of existing drugs by restricting their release parameters. Polymerically-derived nano-DDS were found as a suitable option for oral delivery as well as SLNs due to pharmacokinetic re-modeling of drugs. Mannosylated nano-DDS have upgraded macrophage internalizing of nanosystem and the entrapped drug, provided with minimal toxicity. Cutaneous Leishmaniasis (CL) was tackling by the utilization of nano-DDS designed for topical delivery including niosomes, liposomes, and transfersomes. Transfersomes, however, appears to be superior for this purpose. The nanotechnology-based solution to prevent parasitic resistance is the use of Thiolated drug-loaded and multiple drugs loaded nano-DDS. These surfaces amended nano-DDS possess augmented IC50 values in comparison to conventional drugs and un-modified nano-DDS. Phyto-nano-DDS, another obscure horizon, have also been evaluated for their anti-leishmanial response, however, more intense assessment is a prerequisite. Impoverished Cytotoxic T-cells response followed by Leishmanial antigen proteins delivery have also been vanquished using nano-adjuvants. The eminence of nano-DDS for curtailment of anti-leishmanial chemotherapy and immunization associated challenges are extensively summed up in this review. This expedited approach is ameliorating the Leishmaniasis management successfully. Alongside, total to partial eradication of this disease can be sought along with associated co-morbidities.

Recent Advances in Nanomaterials for Dermal and Transdermal Applications

The stratum corneum, the most superficial layer of the skin, protects the body against environmental hazards and presents a highly selective barrier for the passage of drugs and cosmetic products deeper into the skin and across the skin. Nanomaterials can effectively increase the permeation of active molecules across the stratum corneum and enable their penetration into deeper skin layers, often by interacting with the skin and creating the distinct sites with elevated local concentration, acting as reservoirs. The flux of the molecules from these reservoirs can be either limited to the underlying skin layers (for topical drug and cosmeceutical delivery) or extended across all the sublayers of the epidermis to the blood vessels of the dermis (for transdermal delivery). The type of the nanocarrier and the physicochemical nature of the active substance are among the factors that determine the final skin permeation pattern and the stability of the penetrant in the cutaneous environment. The most widely employed types of nanomaterials for dermal and transdermal applications include solid lipid nanoparticles, nanovesicular carriers, microemulsions, nanoemulsions, and polymeric nanoparticles. The recent advances in the area of nanomaterial-assisted dermal and transdermal delivery are highlighted in this review.

Macrophage targeting with the novel carbopol-based miltefosine-loaded transfersomal gel for the treatment of cutaneous leishmaniasis: in vitro and in vivo analyses

OBJECTIVE

The purpose of this study was to develop novel carbopol-based miltefosine-loaded transfersomal gel (HePCTG) for the treatment of cutaneous leishmaniasis (CL) via efficient targeting of leishmania infected macrophages.

METHODS

Miltefosine-loaded transfersomes (HePCT) were prepared by ethanol injection method followed by their incorporation into carbopol gel to form HePCTG. The prepared HePCT were assessed for physicochemical properties including mean particle size, polydispersity index, zeta potential, entrapment efficiency, morphology, and deformability. Similarly, HePCTG was evaluated for physiochemical and rheological attributes. The in vitro release, skin permeation, skin irritation, anti-leishmanial activity, and in vivo efficacy in BALB/c mice against infected macrophages were also performed for HePCT.

RESULTS

The optimized HePCT displayed a particle size of 168 nm with entrapment efficiency of 92%. HePCTG showed suitable viscosity, pH, and sustained release of the incorporated drug. Furthermore, HePCT and HePCTG demonstrated higher skin permeation than drug solution. The results of macrophage uptake study indicated improved drug intake by passive diffusion. The lower half maximal inhibitory concentration value, selectivity index and higher 50% cytotoxic concentration  value of HePCT compared to that of HePC solution demonstrated the improved anti-leishmanial efficacy and non-toxicity of the formulation. This was further confirmed by the notable reduction in parasite load and lesion size observed in in vivo anti-leishmanial study.

CONCLUSION

It can be stated that the formulated HePCTG can effectively be used for the treatment of CL.

Unravelling Toxoplasma treatment: conventional drugs toward nanomedicine

Toxoplasma gondii is a worldwide protozoan parasite that infects almost all warm-blooded animals. Although human toxoplasmosis is mostly latent, pregnant women and immunocompromised patients need effective treatment. There are drugs of choice for treatment of toxoplasmosis; however, due to their side effects and/or their disease stage-specificity, prescription of them is limited. During recent years, nanomedicine has been employed to overcome limitations of conventional drugs. Here, we provided a state-of-the-art review of experimental toxoplasmosis treatment using nanotechnology.

Chloroform-Injection (CI) and Spontaneous-Phase-Transition (SPT) Are Novel Methods, Simplifying the Fabrication of Liposomes with Versatile Solution to Cholesterol Content and Size Distribution

Intricate formulation methods and/or the use of sophisticated equipment limit the prevalence of liposomal dosage-forms. Simple techniques are developed to assemble amphiphiles into globular lamellae while transiting from the immiscible organic to the aqueous phase. Various parameters are optimized by injecting chloroform solution of amphiphiles into the aqueous phase and subsequent removal of the organic phase. Further simplification is achieved by reorienting amphiphiles through a spontaneous phase transition in a swirling biphasic system during evaporation of the organic phase under vacuum. Although the chloroform injection yields smaller Z-average and poly-dispersity-index the spontaneous phase transition method overrides simplicity and productivity. The increasing solid/solvent ratios results in higher Z-average and broader poly-dispersity-index of liposomes under a given set of experimental conditions, and vice versa. Surface charge dependent large unilamellar vesicles with a narrow distribution have poly-dispersity-index < 0.4 in 10 μM saline. As small and monodisperse liposomes are prerequisites in targeted drug delivery strategies, hence the desired Z-average < 200 d.nm and poly-dispersity-index < 0.15 is obtained through the serial membrane-filtration method. Phosphatidylcholine/water 4 μmol/mL is achieved at a temperature of 10°C below the phase-transition temperature of phospholipids, ensuring suitability for thermolabile entities and high entrapment efficiency. Both methods furnish the de-novo rearrangement of amphiphiles into globular lamellae, aiding in the larger entrapped volume. The immiscible organic phase benefits from its faster and complete removal from the final product. High cholesterol content (55.6 mol%) imparts stability in primary hydration medium at 5 ± 3 °C for 6 months in light-protected type-1 glass vials. Collectively, the reported methods are novel, scalable and time-efficient, yielding high productivity in simple equipment.

Ultradeformable Lipid Vesicles Localize Amphotericin B in the Dermis for the Treatment of Infectious Skin Diseases

Cutaneous fungal and parasitic diseases remain challenging to treat, as available therapies are unable to permeate the skin barrier. Thus, treatment options rely on systemic therapy, which fail to produce high local drug concentrations but can lead to significant systemic toxicity. Amphotericin B (AmB) is highly efficacious in the treatment of both fungal and parasitic diseases such as cutaneous leishmaniasis but is reserved for parenteral administration in patients with severe pathophysiology. Here, we have designed and optimized AmB-transfersomes [93.5% encapsulation efficiency, 150 nm size, and good colloidal stability (-35.02 mV)] that can remain physicochemically stable (>90% drug content) at room temperature and 4 °C over 6 months when lyophilized and stored under desiccated conditions. AmB-transfersomes possessed good permeability across mouse skin (4.91 ± 0.41 μg/cm²/h) and 10-fold higher permeability across synthetic Strat-M membranes. In vivo studies after a single topical application in mice showed permeability and accumulation within the dermis (>25 μg AmB/g skin 6 h postadministration), indicating the delivery of therapeutic amounts of AmB for mycoses and cutaneous leishmaniasis, while a single daily administration in Leishmania (Leishmania) amazonensis infected mice over 10 days, resulted in excellent efficacy (98% reduction in Leishmania parasites). Combining the application of AmB-transfersomes with metallic microneedles in vivo increased the levels in the SC and dermis but was unlikely to elicit transdermal levels. In conclusion, AmB-transfersomes are promising and stable topical nanomedicines that can be readily translated for parasitic and fungal infectious diseases.

Desirability function approach for development of a thermosensitive and bioadhesive nanotransfersome-hydrogel hybrid system for enhanced skin bioavailability and antibacterial activity of cephalexin

Cellulitis is a common bacterial infection of the skin and soft tissues immediately beneath the skin. Despite the successful use of antibiotics in the treatment of infectious diseases, bacterial infections continue to impose significant global health challenges because of the rapid emergence of antibiotic resistance. The aim of this work was to develop an in situ hydrogel forming system containing highly permeable cephalexin-loaded nanotransfersomes (NTs), suitable for antibacterial drug delivery. Response surface design was applied for the optimization of NTs. Cephalexin NTs were prepared using thin-film hydration method and then embedded into a 3D hydrogel network. The in vitro antibacterial activity of the optimized NTs was assayed against indicator bacteria of Staphylococcus aureus (S. aureus). The drug permeation was evaluated using an ex vivo rat skin model. The in vivo efficacy of the cephalexin NT hydrogel was also determined against rat skin infection. The resulting data verified the formation of NTs, the size of which was approximately 192 nm. The cephalexin NTs exhibited higher antibacterial activity against S. aureus as compared to the untreated drug. The NT hydrogel improved drug penetration through the skin after 8 h. When applied on the rat skin for 10 days, the cephalexin NT hydrogel exhibited superior antibacterial activity with normal hair growth and skin appearance as compared with the plain drug hydrogel. These findings suggest that the cephalexin NT-hydrogel system can serve as a valuable drug delivery platform against bacterial infections.