Biodegradable nanoparticles improve oral bioavailability of amphotericin B and show reduced nephrotoxicity compared to intravenous Fungizone

Amphotericin B loaded nanoemulsion: Optimization, characterization and in-vitro activity against L. donovani promastigotes

The present work aimed to develop and evaluate AmB-loaded nano-emulsion (AmB-NE) which will augment the solubility of AmB and lead to enhanced anti-leishmanial activity. The composition of AmB-NE was optimized by systematic screening followed by DoE-extreme vertices mixture design. The optimized NE revealed mean droplet size and PDI of 44.19 ± 5.5 nm, 0.265 ± 0.0723, respectively. The NE could efficiently encapsulate AmB with drug content and efficiency 83.509 ± 0.369% and 81.659 ± 0.013%, respectively. The presence of cholesterol and stearyl amine retarded the release (P < 0.0001) of AmB significantly compared to AmB suspension. The AmB-NE and pure AmB suspension demonstrated the IC50 of 0.06309 μg/mL and 0.3309 μg/mL against L.donovani promastigotes after 48 h incubation. The formulation was robust at all exaggerated stability conditions such as freeze-thaw and centrifugation. These findings indicate that AmB-NE is an attractive approach to treat visceral leishmaniasis with improved activity.

"Click" amphotericin B in prodrug nanoformulations for enhanced systemic fungemia treatment

Severe nephrotoxicity and infusion-related side effects pose significant obstacles to the clinical application of Amphotericin B (AmB) in life-threatening systemic fungal infections. In pursuit of a cost-effective and safe formulation, we have introduced multiple phenylboronic acid (PBA) moieties onto a linear dendritic telodendrimer (TD) scaffold, enabling effective AmB conjugation via boronate chemistry through a rapid, high yield, catalysis-free and dialysis-free "Click" drug loading process. Optimized AmB-TD prodrugs self-assemble into monodispersed micelles characterized by small particle sizes and neutral surface charges. AmB prodrugs sustain drug release in circulation, which is accelerated in response to the acidic pH and Reactive Oxygen Species (ROS) in the infection and inflammation. Prodrugs mitigate the AmB aggregation status, reduce cytotoxicity and hemolytic activity compared to Fungizone®, and demonstrate superior antifungal activity to AmBisome®. AmB-PEG5kBA4 has a comparable maximum tolerated dose (MTD) to AmBisome®, while over 20-fold increase than Fungizone®. A single dose of AmB-PEG5kBA4 demonstrates superior efficacy to Fungizone® and AmBisome® in treating systemic fungal infections in both immunocompetent and immunocompromised mice.

Potential lipid-based strategies of amphotericin B designed for oral administration in clinical application

Amphotericin B (AmB) is regarded as a first-line therapy against life-threatening invasive fungal infections. Due to its poor oral bioavailability, AmB is restricted to intravenous administration in clinical practice. As science continues to move forward, two lipid-based formulations are successfully developed for oral AmB administration, currently undergoing phase I clinical trials. Encouragingly, lipid-AmB conjugates with emulsions also exhibit a better bioavailability, which may be another strategy to design oral AmB formulation in clinical practice. Thus, this review mainly focused on the two lipid-based formulations in clinical trials, and discussed the potential perspectives of AmB-lipid conjugation-loaded nanocochleates and emulsions.

Fluconazole and propolis co-encapsulated in chitosan nanoparticles for the treatment of vulvovaginal candidiasis in a murine model

Vulvovaginal candidiasis (VVC) is a fungal infection caused mainly by Candida albicans. The treatment of VVC with azoles has been impaired due to the increased cases of resistance presented by this pathogen. The aim of the present study was to investigate the antifungal activity of mucoadhesive chitosan nanoparticles encapsulating both green propolis and fluconazole for topical use in the treatment of VVC. The nanoparticles were prepared by the ionic gelation method, resulting in a size of 316.5 nm containing 22 mg/kg of green propolis and 2.4 mg/kg of fluconazole. The nanoparticles were non-toxic in vitro using red blood cells or in vivo in a Galleria mellonella toxicity model. The treatment of female BALB/c mice infected by C. albicans ATCC 10231 with topical nanoparticles co-encapsulating fluconazole and green propolis was effective even using a fluconazole amount 20 times lower than the amount of miconazole nitrate 2% cream. Considering that the mucoadhesive property of chitosan, which is known to allow a prolonged retention time of the compounds at the mucous epithelia, the antifungal potential of the phenols and flavonoids present in green propolis may have favored the effectiveness of this treatment. These results indicate that this formulation of topical use for fluconazole associated with green propolis can be used as a promising approach to therapy for the treatment of VVC, thus contributing to reducing the development of resistance to azoles.

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.

Liposomal Amphotericin B for Treatment of Leishmaniasis: From the Identification of Critical Physicochemical Attributes to the Design of Effective Topical and Oral Formulations

The liposomal amphotericin B (AmB) formulation, AmBisome^®, still represents the best therapeutic option for cutaneous and visceral leishmaniasis. However, its clinical efficacy depends on the patient's immunological status, the clinical manifestation and the endemic region. Moreover, the need for parenteral administration, its side effects and high cost significantly limit its use in developing countries. This review reports the progress achieved thus far toward the understanding of the mechanism responsible for the reduced toxicity of liposomal AmB formulations and the factors that influence their efficacy against leishmaniasis. It also presents the recent advances in the development of more effective liposomal AmB formulations, including topical and oral liposome formulations. The critical role of the AmB aggregation state and release rate in the reduction of drug toxicity and in the drug efficacy by non-invasive routes is emphasized. This paper is expected to guide future research and development of innovative liposomal formulations of AmB.

Limitations of current chemotherapy and future of nanoformulation-based AmB delivery for visceral leishmaniasis-An updated review

Visceral leishmaniasis (VL) is the most lethal of all leishmaniasis diseasesand the second most common parasiticdisease after malaria and,still, categorized as a neglected tropical disease (NTD). According to the latest WHO study, >20 Leishmania species spread 0.7-1.0 million new cases of leishmaniasis each year. VL is caused by the genus, Leishmania donovani (LD), which affects between 50,000 and 90,000 people worldwide each year. Lack of new drug development, increasing drug resistance, toxicity and high cost even with the first line of treatmentof Amphotericin B (AmB), demands new formulation for treatment of VLFurther the lack of a vaccine, allowedthe researchers to develop nanofomulation-based AmB for improved delivery. The limitation of AmB is its kidney and liver toxicity which forced the development of costly liposomal AmB (AmBisome) nanoformulation. Success of AmBisome have inspired and attracted a wide range of AmB nanoformulations ranging from polymeric, solid lipid, liposomal/micellar, metallic, macrophage receptor-targetednanoparticles (NP) and even with sophisticated carbon/quantum dot-based AmBnano delivery systems. Notably, NP-based AmB delivery has shown increased efficacy due to increased uptake, on-target delivery and synergistic impact of NP and AmB. In this review, we have discussed the different forms of leishmaniasis disease and their current treatment options with limitations. The discovery, mechanism of action of AmB, clinical status of AmB and improvement with AmBisome over fungizone (AmB-deoxycholate)for VL treatment was further discussed. At last, the development of various AmB nanoformulation was discussed along with its adavantages over traditional chemotherapy-based delivery.

Effect of Acyl Chain Length on Hydrophobized Cashew Gum Self-Assembling Nanoparticles: Colloidal Properties and Amphotericin B Delivery

Given its many potential applications, cashew gum hydrophobic derivatives have gained increasing attraction in recent years. We report here the effect of acyl chain length on hydrophobized cashew gum derivatives, using acetic, propionic, and butyric anhydrides on self-assembly nanoparticle properties and amphotericin B delivery. Nanoparticles with unimodal particle size distribution, highly negative zeta potential, and low PDI were produced. Butyrate cashew gum nanoparticles presented smaller size (<~100 nm) than acetylated and propionate cashew gum nanoparticles and no cytotoxicity in murine fibroblast cells was observed up to 100 µg/mL for loaded and unloaded nanoparticles. As a proof of concept of the potential use of the developed nanoparticle as a drug carrier formulation, amphotericin B (AmB) was encapsulated and fully characterized in their physicochemical, AmB association and release, stability, and biological aspects. They exhibited average hydrodynamic diameter lower than ~200 nm, high AmB efficiency encapsulations (up to 94.9%), and controlled release. A decrease in AmB release with the increasing of the anhydride chain length was observed, which explains the differences in antifungal activity against Candida albicans strains. An excellent storage colloidal stability was observed for unloaded and loaded AmB without use of surfactant. Considering the AmB delivery, the acyl derivative with low chain length is shown to be the best one, as it has high drug loading and AmB release, as well as low minimum inhibitory concentration against Candida albicans strains.

Orally Administered Amphotericin B Nanoformulations: Physical Properties of Nanoparticle Carriers on Bioavailability and Clinical Relevance

Amphotericin B is an effective polyene antifungal considered as a “gold standard” in the management of fungal infections. Currently, it is administered mainly by IV due to poor aqueous solubility, which precludes its delivery orally. Paradoxically, IV administration is akin to side effects that have not been fully eliminated even with more recent IV formulations. Thus, the need for alternative formulations/route of administration for amphotericin B remains crucial. The oral route offers the possibility of delivering amphotericin B systemically and with diminished side effects; however, enterocyte permeation remains a constraint. Cellular phagocytosis of submicron particles can be used to courier encapsulated drugs. In this regard, nanoparticulate delivery systems have received much attention in the past decade. This review examines the trajectory of orally delivered amphotericin B and discusses key physical factors of nanoformulations that impact bioavailability. The review also explores obstacles that remain and gives a window into the possibility of realizing an oral nanoformulation of amphotericin B in the near future.

Pharmacokinetic study of AmB-NP-GR: a new granule form with amphotericin B to treat leishmaniasis and fungal infections

Amphotericin B (AmB) has been the gold standard to treat systemic fungal infections. The use of AmB is restricted to hospitals because it poses several risks, mainly risks related to its high nephrotoxicity. Given the importance of this drug in medicine, new therapeutics and AmB formulations with nanotechnological improvements are required and could bring many benefits to patients. A new drug formulation with gastro-resistant coated granules has been proposed. The lipid-based system containing AmB was produced and used as raw material in the granulation/coated process. The new developed formulation (AmB-NP-GR) was characterized by optical microscopy, granulometry, and atomic force microscopy (AFM) after disintegration test. AmB-NP-GR showed granular shape, with most granules measured between 250 and 500 µm (37 ± 7% w/w). The AFM images indicated that the granule formulation should disintegrate in the intestine, to release the lipid-based carriers, making them available for absorption and allowing them to reach the blood circulation. The developed formulation was administered to rats in a single dose of 4.0 or 8.0 mg kg^-1 and the pharmacokinetics was studied. The samples were analyzed by liquid chromatography coupled to mass spectrometry. Before the pharmacokinetic studies were conducted, the bioanalytical method was validated according to the EMA guideline and all evaluated parameters agreed with this guideline. The pharmacokinetic results showed that C_max was similar for both doses and that t_max was reached at 4-12 hours for dose of 4.0 mg kg^-1 and 4 hours for dose of 8.0 mg kg^-1. The half-life related to the dose of 8.0 mg kg^-1 increased significantly compared to the dose of 4.0 mg kg^-1 (an increase of more than 3 times). In addition, the mean residence time related to the dose of 8.0 mg kg^-1 was 4 times higher than for the lower dose. The clearance value showed to be higher for the lower dose. Together, these results provide important conclusions for experimental design of other in vivo safety and efficacy studies of AmB-NP-GR.

Road-map of pre-clinical treatment for Visceral Leishmaniasis

Visceral leishmaniasis (VL) or Kala-azar, is the most lethal form of leishmaniasis, is still prevalent in many countries where it is endemic. It is a threat to human life caused by protozoan parasite Leishmania donovani. The severity of the disease is further increased as the treated individuals might have a chance of developing Post Kala-azar Dermal Leishmaniasis (PKDL) in the long run. Moreover, several countries have reported high number of HIV-VL co-infected patients. Therefore, there is a dire need for the development of efficient diagnostic methods and drugs in order to combat the disease and to control the spread of disease. At present, the treatment for VL entirely relies on therapeutic drugs as no vaccine is available yet. Ever since 1900s a series of drugs have been invented and used for treatment of VL; but the need for one such cost-effective treatment that would completely cure the disease with minimal side-effects, low relapse rate with high efficacy and less toxicity remains yet to be fulfilled. Therefore, identifying novel compounds is very crucial to develop potent antileishmanial agents. Thus, this review enlists several instances of drug development, including the pharmacokinetic and pharmacodynamic properties of antileishmanial drugs, different experimental animal models used to investigate the disease progression and to analyze treatment dosage and pharmacological aspect of drugs. Furthermore, the existing gap in drug development and future measures to improve the process are also discussed in this review.

Fabrication and In Vitro Evaluation of pH-Sensitive Polymeric Hydrogels as Controlled Release Carriers

The purpose of the current investigation was to develop chondroitin sulfate/carbopol-co-poly(acrylic acid) (CS/CBP-co-PAA) hydrogels for controlled delivery of diclofenac sodium (DS). Different concentrations of polymers chondroitin sulfate (CS), carbopol 934 (CBP), and monomer acrylic acid (AA) were cross-linked by ethylene glycol dimethylacrylate (EGDMA) in the presence of ammonium peroxodisulfate (APS) (initiator). The fabricated hydrogels were characterized for further experiments. Characterizations such as Scanning electron microscopy (SEM), Thermogravimetric analysis (TGA), Differential scanning calorimetry (DSC), Powder X-ray diffractometry (PXRD), and Fourier transform infrared spectroscopy (FTIR) were conducted to understand the surface morphology, thermodynamic stability, crystallinity of the drug, ingredients, and developed hydrogels. The swelling and drug release studies were conducted at two different pH mediums (pH 1.2 and 7.4), and pH-dependent swelling and drug release was shown due to the presence of functional groups of both polymers and monomers; hence, greater swelling and drug release was observed at the higher pH (pH 7.4). The percent drug release of the developed system and commercially available product cataflam was compared and high controlled release of the drug from the developed system was observed at both low and high pH. The mechanism of drug release from the hydrogels followed Korsmeyer-Peppas model. Conclusively, the current research work demonstrated that the prepared hydrogel could be considered as a suitable candidate for controlled delivery of diclofenac sodium.

Delivery strategies of amphotericin B for invasive fungal infections

Invasive fungal infections (IFIs) represent a growing public concern for clinicians to manage in many medical settings, with substantial associated morbidities and mortalities. Among many current therapeutic options for the treatment of IFIs, amphotericin B (AmB) is the most frequently used drug. AmB is considered as a first-line drug in the clinic that has strong antifungal activity and less resistance. In this review, we summarized the most promising research efforts on nanocarriers for AmB delivery and highlighted their efficacy and safety for treating IFIs. We have also discussed the mechanism of actions of AmB, rationale for treating IFIs, and recent advances in formulating AmB for clinical use. Finally, this review discusses some practical considerations and provides recommendations for future studies in applying AmB for combating IFIs.

Current status of nanoscale drug delivery and the future of nano-vaccine development for leishmaniasis - A review

The study of tropical diseases like leishmaniasis, a parasitic disease, has not received much attention even though it is the second-largest infectious disease after malaria. As per the WHO report, a total of 0.7-1.0 million new leishmaniasis cases, which are spread by 23 Leishmania species in more than 98 countries, are estimated with an alarming 26,000-65,000 death toll every year. Lack of potential vaccines along with the cost and toxicity of amphotericin B (AmB), the most common drug for the treatment of leishmaniasis, has raised the interest significantly for new formulations and drug delivery systems including nanoparticle-based delivery as anti-leishmanial agents. The size, shape, and high surface area to volume ratio of different NPs make them ideal for many biological applications. The delivery of drugs through liposome, polymeric, and solid-lipid NPs provides the advantage of high biocomatibilty of the carrier with reduced toxicity. Importantly, NP-based delivery has shown improved efficacy due to targeted delivery of the payload and synergistic action of NP and payload on the target. This review analyses the advantage of NP-based delivery over standard chemotherapy and natural product-based delivery system. The role of different physicochemical properties of a nanoscale delivery system is discussed. Further, different ways of nanoformulation delivery ranging from liposome, niosomes, polymeric, metallic, solid-lipid NPs were updated along with the possible mechanisms of action against the parasite. The status of current nano-vaccines and the future potential of NP-based vaccine are elaborated here.

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.

The enhancing antifungal effect of AD1 aptamer-functionalized amphotericin B-loaded PLGA-PEG nanoparticles with a low-frequency and low-intensity ultrasound exposure on C.albicans biofilm through targeted effect

The prevalence and fatality rates with fungal biofilm-associated infections urgently need to develop targeted therapeutic approaches to augment the action of antifungal drugs. This study developed amphotericin B-loaded PLGA-PEG nanoparticles (AmB-NPs) with AD1 aptamer conjugation on its surface via an EDC/NHS technique. Their high nuclease resistance of the conjugation was confirmed by PAGE gel electrophoresis. The targeting and toxicity of AD1-AmB-NPs in the subcutaneous C. albicans infection model were evaluated. AD1-AmB-NPs can bind to different morphological forms(including yeast cells, germ tubes, hyphae) of C. albicans biofilms and extracellular matrix material. Low-frequency and low-intensity ultrasound (LFU, with a fixed frequency of 42 kHz, at the intensity of 0.30 W/cm² for 15 min) significantly promoted permeability of the biofilm and allowed AD1-AmB-NPs into the deepest layers of the biofilm. After 7 days of treatment, the combination treatment of AD1-AmB-NPs and LFU, kills at least 99% of the biofilm fungal population in vivo comparison with ultrasound alone or AD1-AmB-NPs alone, and returned to normal subcutaneously. Our data suggest that the combined strategy of AD1-AmB-NPs and ultrasound treatment selective delivered of therapeutic drugs to the infection site and exhibited significant synergistic antifungal effects.

Alginate-based drug oral targeting using bio-micro/nano encapsulation technologies

INTRODUCTION

Oral delivery is the most common administrated drug delivery path. However, oral administration of lipophilic drugs has some limitations: they have poor dose-response due to low and varied dissolution kinetics and oral bioavailability with sub-optimal dissolution within the aqueous gastrointestinal microenvironment. Therefore, there is a need for robust formulating methods that protect the drug until it reaches to its optimum absorption site, allowing its optimum pharmacological effects via increasing its intestinal permeation and bioavailability.

AREA COVERED

Herein, we provide insights on orally administered lipophilic drug delivery systems. The detailed description of the obstacles associated with the oral bioavailability of lipophilic drugs are also discussed. Following this, techniques to overcome these obstacles with much emphasis on optimal safety and efficacy are addressed. Newly designed ionic vibrational jet flow encapsulation technology has enormous growth in lipophilic drug delivery systems, which is discussed thereafter.

EXPERT OPINION

Researchers have shown interest in drug's encapsulation. A combination of drug-bile acid and microencapsulation methods can be one promising strategy to improve the oral delivery of lipophilic drugs. However, the most critical aspect of this approach is the selection of bile acids, polymer, and encapsulation technology.

Development of Amphotericin B Micellar Formulations Based on Copolymers of Poly(ethylene glycol) and Poly(ε-caprolactone) Conjugated with Retinol

Amphotericin B (AmB) is a broad spectrum of antifungal drug used to treat antifungal diseases. However, due to the high toxicity of AmB, treated patients may suffer the risk of side effects, such as renal failure. Nanoencapsulation strategies have been reported to elicit low toxicity, albeit most of them possess low encapsulation efficiency. The aim of this research is to develop micellar delivery systems for AmB with reduced toxicity while maintaining its affectivity by employing retinol (RET)-conjugated amphiphilic block copolymers (ABCs) as precursors. Copolymers composed of poly(ε-caprolactone) (A) and polyethylenglycol (B) of types AB and ABA were synthesized by ring opening polymerization and subsequently conjugated with RET by Steglich esterification. 1H-NMR spectroscopy was used to corroborate the structure of copolymers and their conjugates and determine their molecular weights. Analysis by gel permeation chromatography also found that the materials have narrow distributions. The resulting copolymers were used as precursors for delivery systems of AmB, thus reducing its aggregation and consequently causing a low haemolytic effect. Upon conjugation with RET, the encapsulation capacity was enhanced from approximately 2 wt % for AB and ABA copolymers to 10 wt %. AmB encapsulated in polymer micelles presented improved antifungal efficiency against Candida albicans and Candida auris strains compared with Fungizone®, as deduced from the low minimum inhibitory concentration.

Amphotericin B Loaded Nanostructured Lipid Carriers for Parenteral Delivery: Characterization, Antifungal and In vitro Toxicity Assessment

BACKGROUND

Amphotericin B (AmB) is important for the treatment of systemic fungal infections. Nowadays, only intravenous administration (IV) of AmB has been available due to its low aqueous solubility. Two forms of AmB are available. The first is Fungizone®, a mixture of AmB and sodium deoxcycholate that produces severe nephrotoxicity. The second are lipid-based formulations that reduce nephrotoxicity, but they are costly and require higher dose than Fungizone®. Thus, a cheaper delivery system with reduced AmB toxicity is required.

OBJECTIVE

To develop and characterize AmB loaded-nanostructured lipid carriers (AmB-loaded NLCs) for IV administration to reduce AmB toxicity.

METHODS

AmB-loaded NLCs with different solid lipids were prepared by the high-pressure homogenization technique. Their physicochemical properties and the drug release profile were examined. The molecular structure of AmB, antifungal and hemolysis activities of developed AmB-loaded NLCs were also evaluated.

RESULTS

AmB-loaded NLCs ~110 to ~140 nm in diameter were successfully produced with a zeta potential of ~-19 mV and entrapment efficiency of ~75%. In vitro release showed fast release characteristics. AmB-loaded NLCs could reduce the AmB molecular aggregation as evident from the absorbance ratio of the first to the fourth peak showing a partial aggregation of AmB. This result suggested that AmB-loaded NLCs could offer less nephrotoxicity compared to Fungizone®. In vitro antifungal activity of AmB-loaded NLCs showed a minimum inhibitory concentration of 0.25 µgmL-1.

CONCLUSION

AmB-loaded NLCs present high potential carriers for effective IV treatment with prolonged circulation time and reduced toxicity.

Efficient antileishmanial activity of amphotericin B and piperine entrapped in enteric coated guar gum nanoparticles

Amphotericin B (AmB) exhibits potential antileishmanial activity, with only a little rate of recurrence. However, low bioavailability and severe nephrotoxicity are among the major shortcomings of AmB-based therapy. Various AmB nanoformulations have been developed, which to an extent, have reduced its toxicity and increased the drug efficacy. To further reduce the nonspecific tissue distribution and the cost of the treatment, the current AmB-based formulations require additional improvements. Combination of natural bioenhancers with AmB is expected to further increase its bioavailability. Therefore, we developed a nanoformulation of AmB and piperine (Pip), a plant alkaloid, known to enhance the bioavailability of various drugs, by entrapping them in guar gum, a macrophage targeting polymer. Owing to the ease of oral delivery, these nanoparticles (NPs) were coated with eudragit to make them suitable for oral administration. The formulated eudragit-coated AmB and Pip-loaded NPs (Eu-HDGG-AmB-Pip-NPs) exhibited controlled release of the loaded therapeutic agents and protected the drug from acidic pH. These NPs exhibited effective suppression of growth of both promastigotes and amastigotes of Leishmania donovani parasite under in vitro. In vivo evaluation of these NPs for therapeutic efficacy in golden hamster-L. donovani model demonstrated enhanced drug bioavailability, non-nephrotoxic nature, and potential antileishmanial activity with up to 96% inhibition of the parasite. Graphical abstract.

Preparation, Characterization, and In Vivo Pharmacokinetic Study of the Supercritical Fluid-Processed Liposomal Amphotericin B

Here, we aimed to prepare and optimize liposomal amphotericin B (AmB) while using the supercritical fluid of carbon dioxide (SCF-CO₂) method and investigate the characteristics and pharmacokinetics of the SCF-CO₂-processed liposomal AmB. Liposomes containing phospholipids, ascorbic acid (vit C), and cholesterol were prepared by the SCF-CO₂ method at an optimized pressure and temperature; conventional liposomes were also prepared using the thin film hydration method and then compared with the SCF-CO₂-processed-liposomes. The optimized formulation was evaluated by in vitro hemolysis tests on rat erythrocytes and in vivo pharmacokinetics after intravenous administration to Sprague-Dawley rats and compared with a marketed AmB micellar formulation, Fungizone^®, and a liposomal formulation, AmBisome^®. The results of the characterization studies demonstrated that the SCF-CO₂-processed-liposomes were spherical particles with an average particle size of 137 nm (after homogenization) and drug encapsulation efficiency (EE) was about 90%. After freeze-drying, mean particle size, EE, and zeta potential were not significantly changed. The stability study of the liposomes showed that liposomal AmB that was prepared by the SCF method was stable over time. In vivo pharmacokinetics revealed that the SCF-CO₂-processed-liposomes were bioequivalent to AmBisome^®; the hemolytic test depicted less hematotoxicity than Fungizone^®. Therefore, this method could serve as a potential alternative for preparing liposomal AmB for industrial applications.

Anti-leishmanial Nanotherapeutics: A Current Perspective

Background:

Leishmaniasis is a dreaded disease caused by protozoan parasites belonging to the genus Leishmania which results in significant morbidity and mortality worldwide. There are no vaccines available currently for the treatment of Leishmaniasis and chemotherapy still remains the mainstay for anti-leishmanial therapeutics. However, toxicity, reduced bioavailability, high cost and chemoresistance are the principal problems which limit the use of the available drugs. In this context, anti-leishmanial nanotherapeutics may show the way for effective treatment of this dreaded disease.

Methods:

We carried out extensive literature search of bibliographic database using keywords strictly within the scope of the present study for peer reviewed research articles. We focused specifically on articles related to the application of nanotechnology in drug development, drug delivery and vaccine delivery for anti-leishmanial therapeutics.

Results:

This study shows the immense potential of the application of nanotechnology in the field of anti-leishmanial therapeutics. This will aid the targeted delivery of different drugs which is expected to increase the bioavailability, reduce toxicity and also address the problem of chemoresistance.

Conclusion:

We surmise that exciting research in the field of anti-leishmanial nanotherapeutics is already showing the promise for effective applicability. Though direct use of nanoparticles as therapeutic agents does not seem to be a good option, the application of nanotechnology in this field for vaccine development is still in its early days. The nano based drug delivery system for anti-leishmanial therapeutics has evolved considerably over the past ten years and holds the potential to drastically change the landscape of anti-leishmanial therapeutics.

Novel and safe single-dose treatment of cutaneous leishmaniasis with implantable amphotericin B-loaded microparticles

The development of an effective amphotericin B (AmB) topical formulation to replace the systemically toxic injections currently used in cutaneous leishmaniasis (CL) treatment is challenging due to poor absorption through the skin. Aiming at an effective local chemotherapy, we designed PLGA (poly(lactide-co-glycolide acid) microparticles loaded with deoxycholate amphotericin B (d-AmB) for both macrophage intracellular targeting and sustained extracellular release. For that, d-AmB/PLGA microparticles with sizes ranging from 0.5 μm to 20 μm were synthesized and tested both in vitro and in vivo. In vitro, d-AmB/PLGA was more selectively active against intracellular amastigotes of Leishmania amazonensis than free d-AmB (selectivity index = 50 and 25, respectively). In vivo, the efficacy of a single intralesional (i.l) injection with d-AmB/PLGA was determined in early and established BALB/c mouse ear lesions. In early lesions, a single injection given on day 10 of infection was more effective in controlling parasite growth than eight i.l. injections with free d-AmB, as measured on day 120. Such d-AmB/PLGA injection was also effective in established lesions (day 30), leading to 97% parasite burden reduction, as compared with d-AmB or liposomal AmB (Ambisome®) i.l. injection containing the same AmB dose. Pharmacokinetic studies showed that following d-AmB/PLGA injection, AmB leaked slower from non-infected than infected ears, yet remaining in the ear tissue for as long as 30 days. Of interest, AmB was not detectable in the circulating plasma for at least two weeks of d-AmB/PLGA injection, contrasting with the rapid and durable (2 days) detection after free d-AmB injection. Despite the transient ear swelling and local cell infiltration, no alterations in AST, ALT and creatinine serum levels was induced by d-AmB/PLGA. For its approved components, local efficacy, and single-dose applicability, this novel and safe AmB microparticle depot formulation has strong potential as a new therapy for human CL.

Exploiting knowledge on pharmacodynamics-pharmacokinetics for accelerated anti-leishmanial drug discovery/development

Introduction: Being on the top list of neglected tropical diseases, leishmaniasis has been marked for elimination by 2020. In the light of small armamentarium of drugs and their associated drawbacks, the understanding of pharmacodynamics and/or pharmacokinetics becomes a priority to achieve and sustain disease elimination. Areas covered: The authors have looked into pharmacological aspects of existing and emerging drugs for treatment of leishmaniasis. An in-depth understanding of pharmacodynamics and pharmacokinetics (PKPD) provides a rationale for drug designing and optimizing the treatment strategies. It forms a key to prevent drug resistance and avoid drug-associated adverse effects. The authors have compiled the researches on the PKPD of different anti-leishmanial formulations that have the potential for improved and/or effective disease intervention. Expert opinion: Understanding the pharmacological aspects of drugs forms the basis for the clinical application of novel drugs. Tailoring drug dosage and individualized treatment can avoid the adverse events and bridge gap between the in vitro models and their clinical application. An integrated approach, with pragmatic use of technological advances can improve phenotypic screening and physiochemical properties of novel drugs. Concomitantly, this can serve to improve clinical efficacies, reduce the incidence of relapse and accelerate the drug discovery/development process for leishmaniasis elimination.

Synergistic Antifungal Effect of Amphotericin B-Loaded Poly(Lactic-Co-Glycolic Acid) Nanoparticles and Ultrasound against Candida albicans Biofilms

Candida albicans is a human opportunistic pathogen that causes superficial and life-threatening infections. An important reason for the failure of current antifungal drugs is related to biofilm formation, mostly associated with implanted medical devices. The present study investigated the synergistic antifungal efficacy of low-frequency and low-intensity ultrasound combined with amphotericin B (AmB)-loaded poly(lactic-co-glycolic acid) (PLGA) nanoparticles (AmB-NPs) against C. albicans biofilms. AmB-NPs were prepared by a double-emulsion method and demonstrated lower toxicity than free AmB. We then established biofilms and treated them with ultrasound and AmB-NPs separately or jointly in vitro and in vivo The results demonstrated that the activity, biomass, and proteinase and phospholipase activities of biofilms were decreased significantly after the combination treatment of AmB-NPs with 42 kHz of ultrasound irradiation at an intensity of 0.30 W/cm² for 15 min compared with the controls, with AmB alone, or with ultrasound treatment alone (P < 0.01). The morphology of the biofilms was altered remarkably after joint treatment based on confocal laser scanning microscopy (CLSM), especially in regard to reduced thickness and loosened structure. Furthermore, the same synergistic effects were found in a subcutaneous catheter biofilm rat model. The number of CFU from the catheter exhibited a significant reduction after joint treatment with AmB-NP and ultrasound for seven continuous days, and CLSM and scanning electron microscopy (SEM) images revealed that the biofilm on the catheter surface was substantially eliminated. This method may provide a new noninvasive, safe, and effective therapy for C. albicans biofilm infection.

Antifungal and Mucoadhesive Properties of an Orally Administered Chitosan-Coated Amphotericin B Nanostructured Lipid Carrier (NLC)

Surface-modified nanostructured lipid carriers (NLC) represent a promising mode of drug delivery used to enhance retention of drugs at absorption site. Formulated chitosan-coated amphotericin-B-loaded NLC (ChiAmp NLC) had a size of 394.4 ± 6.4 nm, encapsulation and loading efficiencies of 86.0 ± 3% and 11.0 ± 0.1% respectively. Amphotericin-B release from NLCs was biphasic with no changes in physical properties upon exposure to simulated gastrointestinal conditions. Antifungal properties of Amphotericin-B and ChiAmpB NLC were comparable but ChiAmpB NLC was twice less toxic to red blood cells and ten times safer on HT-29 cell lines. In vitro mucoadhesion data were observed ex vivo, where ChiAmpB NLC resulted in higher retention within the small intestine compared to the uncoated formulation. The data strongly offers the possibility of orally administering a non-toxic, yet effective Amphotericin-B nanoformulation for the treatment of systemic fungal infections.

Effect of Acyclovir Solid Lipid Nanoparticles for the Treatment of Herpes Simplex Virus (HSV) Infection in an Animal Model of HSV-1 Infection

BACKGROUND

Acyclovir use is limited by a high frequency of administration of five times a day and low bioavailability. This leads to poor patient compliance.

OBJECTIVES

To overcome the problem of frequent dosing, we used nanotechnology platform to evaluate the proof of concept of substituting multiple daily doses of acyclovir with a single dose.

METHODS

Acyclovir was formulated as solid lipid nanoparticles (SLN). The nanoparticles were characterized for particle size, surface charge and morphology and in vitro drug release. The pharmacokinetic and pharmacodynamic of SLN acyclovir were compared with conventional acyclovir in a mouse model.

RESULTS

SLN showed drug loading of 90.22% with 67.44% encapsulation efficiency. Particle size was found to be of 131 ± 41.41 nm. In vitro drug release showed 100% release in SIF in 7 days. AUC0-∞ (119.43 ± 28.74 μg/ml h), AUMC0-∞ (14469 ± 4261.16 μg/ml h) and MRT (120.10 ± 9.21 h) were significantly higher for ACV SLN as compared to ACV AUC0-∞ (12.22 ± 2.47 μg/ml h), AUMC0-∞ (28.78 ± 30.16 μg/ml h) and MRT (2.07 ± 1.77 h), respectively (p<0.05). In mouse model, a single dose of ACV SLN was found to be equivalent to ACV administered as 400mg TID for 5 days in respect to lesion score and time of healing.

CONCLUSION

The proof of concept of sustained-release acyclovir enabling administration as a single dose was thus demonstrated.

Amphotericin B Loaded Chitosan Nanoparticles: Implication of Bile Salt Stabilization on Gastrointestinal Stability, Permeability and Oral Bioavailability

Through current investigation, we presented a lucrative way to formulate amphotericin B loaded bile salt stabilized carbohydrate polymer i.e. chitosan nanoparticles (NPs) for enhancing gastrointestinal stability of NPs thereby increasing the oral bioavailability of the drug. NPs were prepared using ionic gelation method, and stabilized using bile salt to provide gastric pH stability to chitosan NPs. NPs were optimized on different parameters such as particle size, encapsulation efficiency and estimated for their in vitro and in vivo performance. Developed NPs presented a higher stability in gastrointestinal milieu, reduced haemolytic toxicity and significantly higher uptake in Caco-2 cell lines followed by increased bioavailability as compared to naive drug, marketed formulation i.e. Fungizone® and uncoated chitosan NPs. Biochemical parameters and histology further substantiated the lower toxicity. In nutshell, the present research explored the bioadhesive and higher uptake potential of cationic carbohydrate polymer at the same time along with bile salts for stabilization of NPs in gastric milieu.

Getting the Jump on the Development of Bullfrog Oil Microemulsions: a Nanocarrier for Amphotericin B Intended for Antifungal Treatment

Amphotericin B (AmB), a potent antifungal drug, presents physicochemical characteristics that impair the development of suitable dosage forms. In order to overcome the AmB insolubility, several lipid carriers such as microemulsions have been developed. In this context, the bullfrog oil stands out as an eligible oily phase component, since its cholesterol composition may favor the AmB incorporation. Thus, the aim of this study was to develop a microemulsion based on bullfrog oil containing AmB. Moreover, its thermal stability, antifungal activity, and cytotoxicity in vitro were evaluated. The microemulsion formulation was produced using the pseudo-ternary phase diagram (PTPD) approach and the AmB was incorporated based on the pH variation technique. The antifungal activity was evaluated by determination of minimal inhibitory concentration (MIC) against different species of Candida spp. and Trichosporon asahii. The bullfrog oil microemulsion, stabilized with 16.8% of a surfactant blend, presented an average droplet size of 26.50 ± 0.14 nm and a polydispersity index of 0.167 ± 0.006. This system was able to entrap AmB up to 2 mg mL^-1. The use of bullfrog oil as oily phase allowed an improvement of the thermal stability of the system. The MIC assay results revealed a growth inhibition for different strains of Candida spp. and were able to enhance the activity of AmB against T. asahii. The microemulsion was also able to reduce the AmB toxicity. Finally, the developed microemulsion showed to be a suitable system to incorporate AmB, improving the system's thermal stability, increasing the antifungal activity, and reducing the toxicity of this drug.

Antileishmanial Activity of Amphotericin B-loaded-PLGA Nanoparticles: An Overview

In recent decades, nanotechnology has made phenomenal strides in the pharmaceutical field, favouring the improvement of the biopharmaceutical properties of many active compounds. Many liposome-based formulations containing antitumor, antioxidant and antifungal compounds are presently on the market and are used daily (for example Doxil^®/Caelyx^® and Ambisome^®). Polymeric nanoparticles have also been used to entrap many active compounds with the aim of improving their pharmacological activity, bioavailability and plasmatic half-life while decreasing their side effects. The modulation of the structural/morphological properties of nanoparticles allows us to influence various technological parameters, such as the loading capacity and/or the release profile of the encapsulated drug(s). Amongst the biocompatible polymers, poly(D,L-lactide) (PLA), poly(D,L-glycolide) (PLG) and their co-polymers poly(lactide-co-glycolide) (PLGA) are the most frequently employed due to their approval by the FDA for human use. The aim of this review is to provide a description of the foremost recent investigations based on the encapsulation of amphotericin B in PLGA nanoparticles, in order to furnish an overview of the technological properties of novel colloidal formulations useful in the treatment of Leishmaniasis. The pharmacological efficacy of the drug after nanoencapsulation will be compared to the commercial formulations of the drug (i.e., Fungizone^®, Ambisome^®, Amphocil^® and Abelcet^®).

Lyotropic Liquid Crystalline Nanoparticles of Amphotericin B: Implication of Phytantriol and Glyceryl Monooleate on Bioavailability Enhancement

Implication of different dietary specific lipids such as phytantriol (PT) and glyceryl monooleate (GMO) on enhancing the oral bioavailability of amphotericin B (AmB) was examined. Liquid crystalline nanoparticles (LCNPs) were prepared using hydrotrope method, followed by in vitro characterization, Caco-2 cell monolayer uptake, and in vivo pharmacokinetic and toxicity evaluation. Optimized AmB-LCNPs displayed small particle size (< 210 nm) with a narrow distribution (~ 0.2), sustained drug release and high gastrointestinal stability, and reduced hemolytic toxicity. PLCNPs presented slower release, i.e., ~ 80% as compared to ~ 90% release in case of GLCNPs after 120 h. Significantly higher uptake in Caco-2 monolayer substantiated the role of LCNPs in increasing the intestinal permeability followed by increased drug titer in plasma. Pharmacokinetic studies demonstrated potential of PT in enhancing the bioavailability (approximately sixfold) w.r.t. of its native counterpart with reduced nephrotoxicity as presented by reduced nephrotoxicity biomarkers and histology studies. These studies established usefulness of PLCNPs over GLCNPs and plain drug. It can be concluded that acid-resistant lipid, PT, can be utilized efficiently as an alternate lipid for the preparation of LCNPs to enhance bioavailability and to reduce nephrotoxicity of the drug as compared to other frequently used lipid, i.e., GMO.

Improving the skin penetration and antifebrile activity of ibuprofen by preparing nanoparticles using emulsion solvent evaporation method

Ibuprofen (IBU) is an effective analgesic, non-steroidal anti-inflammatory drug. Unfortunately, oral IBU can cause adverse gastrointestinal drug reactions, such as bleeding and ulcerations, and increases the risk for stomach or intestinal perforations. In this study, IBU nanoparticles (IBU-NPs) were prepared through emulsion solvent evaporation and freeze-drying to improve their solubility. IBU nanoemulsion and nanosuspension were optimized through a single-factor experiment. IBU-NPs with a mean particle size of 216.9±10.7nm were produced under optimum conditions. These IBU-NPs were characterized by using scanning electron microscopy, X-ray diffraction, differential scanning calorimetry, and residual solvent determination to determine their solvent residue, equilibrium solubility, dissolution rate, in vitro transdermal rate, transdermal bioavailability, and antifebrile experiment for febrile rats. The morphological characteristic of IBU-NPs showed porous clusters. Analysis results indicated that the prepared IBU-NPs have low crystallinity. Residual amounts of ethanol and chloroform were 170 and 9.6ppm, respectively, which were less than the ICH limit for class II. Measurement analysis showed that the IBU-NPs were converted underwent amorphous states after preparation, but the chemical structure of the IBU-NPs was unchanged. Transdermal bioavailability of IBU in the IBU-NP group improved significantly compared with oral and transdermal raw IBU. Furthermore, the IBU-NP transdermal gel exhibited a high and stable cooling rate and a long cooling duration in febrile rats. In comparison with the raw oral IBU and raw IBU transdermal gel, the IBU-NP transdermal gel manifested better efficacy at low and mid doses. Basing from the results, we conclude that IBU-NPs can be applied in transdermal delivery formulations and have potential application value for non-oral administration.

Nanostructured delivery systems with improved leishmanicidal activity: a critical review

Leishmaniasis is a vector-borne zoonotic disease caused by protozoan parasites of the genus Leishmania, which are responsible for numerous clinical manifestations, such as cutaneous, visceral, and mucocutaneous leishmaniasis, depending on the site of infection for particular species. These complexities threaten 350 million people in 98 countries worldwide. Amastigotes living within macrophage phagolysosomes are the principal target of antileishmanial treatment, but these are not an easy target as drugs must overcome major structural barriers. Furthermore, limitations on current therapy are related to efficacy, toxicity, and cost, as well as the length of treatment, which can increase parasitic resistance. Nanotechnology has emerged as an attractive alternative as conventional drugs delivered by nanosized carriers have improved bioavailability and reduced toxicity, together with other characteristics that help to relieve the burden of this disease. The significance of using colloidal carriers loaded with active agents derives from the physiological uptake route of intravenous administered nanosystems (the phagocyte system). Nanosystems are thus able to promote a high drug concentration in intracellular mononuclear phagocyte system (MPS)-infected cells. Moreover, the versatility of nanometric drug delivery systems for the deliberate transport of a range of molecules plays a pivotal role in the design of therapeutic strategies against leishmaniasis. This review discusses studies on nanocarriers that have greatly contributed to improving the efficacy of antileishmaniasis drugs, presenting a critical review and some suggestions for improving drug delivery.

Oral administration of amphotericin B nanoparticles: antifungal activity, bioavailability and toxicity in rats

Amphotericin B (AMB) is used most commonly in severe systemic life-threatening fungal infections. There is currently an unmet need for an efficacious (AMB) formulation amenable to oral administration with better bioavailability and lower nephrotoxicity. Novel PEGylated polylactic-polyglycolic acid copolymer (PLGA-PEG) nanoparticles (NPs) formulations of AMB were therefore studied for their ability to kill Candida albicans (C. albicans). The antifungal activity of AMB formulations was assessed in C. albicans. Its bioavalability was investigated in nine groups of rats (n = 6). Toxicity was examined by an in vitro blood hemolysis assay, and in vivo nephrotoxicity after single and multiple dosing for a week by blood urea nitrogen (BUN) and plasma creatinine (PCr) measurements. The MIC of AMB loaded to PLGA-PEG NPs against C. albicans was reduced two to threefold compared with free AMB. Novel oral AMB delivery loaded to PLGA-PEG NPs was markedly systemically available compared to Fungizone® in rats. The addition of 2% of GA to the AMB formulation significantly (p < 0.05) improved the bioavailability from 1.5 to 10.5% and the relative bioavailability was > 790% that of Fungizone®. The novel AMB formulations showed minimal toxicity and better efficacy compared to Fungizone®. No nephrotoxicity in rats was detected after a week of multiple dosing of AMB NPs based on BUN and PCr, which remained at normal levels. An oral delivery system of AMB-loaded to PLGA-PEG NPs with better efficacy and minimal toxicity was formulated. The addition of glycyrrhizic acid (GA) to AMB NPs formulation resulted in a significant oral absorption and improved bioavailability in rats.