Search

In an effort to increase the oral bioavailability of Amphotericin B (AmB), a pH-sensitive drug carrier composed of Tragacanth (Trag) and acrylic acid (AAc) was prepared using γ-irradiation. The swelling behavior of (Trag/AAc) hydrogels was characterized as a function of pH and ionic strength of the swelling medium. The obtained swelling indices revealed the ability of the prepared hydrogel to protect a loaded drug in stomach-simulated medium (Fickian behavior) and to release such drug in intestinal-simulated medium (non-Fickian behavior). In vitro release studies of the antifungal (AmB) were performed to evaluate the hydrogel potential as a drug carrier. The antifungal activity of the prepared oral formulation was investigated in a mouse model of systemic candidiasis. Data revealed that (Trag/AAc)-AmB has a potent antifungal efficacy as demonstrated by prolonging the survival time and reducing the tissue fungal burden, serum antibody titers, as well as inflammatory cytokines in kidney and liver tissues. Furthermore, in vivo toxicity of (Trag/AAc)-AmB was assessed via measuring kidney and liver functions, and results displayed the safety of this novel AmB formulation which was confirmed by histopathological examination. Overall, results indicated that the prepared (Trag/AAc)-AmB is an effective oral delivery system for AmB with better bioavailability and minimal toxicity and could represent a promising approach for improving the therapeutic index of the drug.

Much attention has been paid to nanoparticle-based drug delivery systems to selectively deliver drugs to target organs and tissues. In this study, AmBisome, an antimycotic nanomedicine containing amphotericin B, was chosen as a typical nanomedicine, and analyzed using dynamic light scattering (DLS), an easy method to measure size, and size distribution, atomic force microscopy (AFM) and high-performance liquid chromatography (HPLC). AFM allowed the analysis of shape, besides a detailed size and size distribution. HPLC is useful to quantify the released amount of amphotericin B as it succeeded in a rapid separation of AmBisome and free amphotericin B. The aggregation or collapse of AmBisome and release of amphotericin B occurred upon 75% methanol addition or dilution with buffer around pH 4. Therefore, it is important to analyze nanomedicines using multiple analytical methods, and to integrate them for the quality and quantity evaluation of nanomedicines., (Copyright © 2017 Elsevier B.V. All rights reserved.)

The aim of this study was to evaluate mannose-anchored thiolated chitosan (MTC) based nanocarriers (NCs) for enhanced permeability, improved oral bioavailability and anti-parasitic potential of amphotericin B (AmB). Transgenic Leishmania donovani parasites expressing red fluorescent protein DsRed2 and imaging-flow cytometry was used to investigate parasitic burdens inside bone marrow-derived macrophages ex vivo. Cytokine estimation revealed that MTC nanocarriers activated the macrophages to impart an explicit immune response by higher production of TNF-α and IL-12 as compared to control. Cells treated with MTC NCs showed a significantly higher magnitude of nitrite and propidium iodide (PI) fluorescence intensity in contrast to cells treated with AmB. Concerning to apparent permeability coefficient (P app ) results, the MTC NCs formulation displayed more specific permeation across the Caco-2 cell monolayer as compared to AmB. The half-life of MTC NCs was about 3.3-fold persistent than oral AmB used as positive control. Also, t oral bioavailability of AmB was increased to 6.4-fold for MTC NCs compared to AmB for positive control. Acute oral evaluation indicated that MTC NCs were significantly less toxic compared to the AmB. Based on these findings, MTC NCs seems to be promising for significant oral absorption and improved oral bioavailability of AmB in leishmaniasis chemotherapy.

The purpose of this study was to evaluate the most appropriate conditions to generate silver nanoparticles (AgNPs) loaded with a potent antimycotic drug like amphotericin B (AmB), characterize the physicochemical properties, and to evaluate the cytotoxic effect and biological activity of these new nanostructures as a potential nanocarrier for hydrophobic drugs. It was determined that the optimal molar ratio between Ag and AmB is 1/1 given the uniformity of size around 170 nm of the nanoparticles generated as well as their strongly negative ζ potential of -35 mV, a condition that favors repulsions between AgNPs and inhibiting their aggregation. In this condition, only 0.8 mg.mL-1 of Ag is needed to solubilize 5 mg.mL-1 of AmB, a concentration currently used in commercial formulations. It is important to emphasize that the loading capacity (w/w) of this nanostructure is much higher than that of micellar and liposomal formulations. These AgNP-AmB nanoparticles retain both the bactericidal effect of silver and the cytotoxic and antifungal effect of AmB. However, it was shown that these nanoparticles are spontaneously associated with plasma lipoproteins (LDL and HDL), inhibiting their cytotoxic effects on red blood cells and on at least two cell lines, Vero and H1299 and slightly reducing its bactericidal effect on P. aeruginosa. In contrast, the antifungal effect of the formulation is maintained and is even higher than that when the nanoparticle is not associated with lipoproteins, indicating that this association is of the reversible type. The characterization of these nanoparticles is discussed as a potential new model formulation able to improve the antifungal therapeutic efficiency of AmB., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.)

Background: Amphotericin B (AmB), a polyene antibiotic used for the treatment of fungal and leishmanial infections is virtually insoluble in water and exhibits severe toxicity. AmB has been conjugated to various soluble polymers for improving its solubility and reducing its toxicity. Conjugating AmB to a polysorbate surfactant such as polyoxyethylene sorbitan monolaurate (Tween 20), was examined to improve its solubility and reduce its toxicity., Methods: AmB was coupled to Tween 20 via carbamate linkage at 15 and 30 wt% concentrations in high yield by activating the hydroxyl groups of the surfactant using p- nitrophenyl chloroformate. The conjugates were characterized by using 1H NMR, IR, UV and HPLC analysis and were examined for their toxicity, and anti-fungal and anti-leishmanial activities in vitro., Results: Tween-AmB conjugates were soluble to the extent of 10 mg/mL in water, showed improved critical micelle concentration in comparison with AmB, exhibited negligible hemolytic potential even at a concentration of 1000 µM and were not toxic against human embryonic kidney cell line (HEK293T) at similar concentrations. The conjugates showed potent anti-fungal activity against Candida albicans, Candida parapsilosis and Cryptococcus neoformans and anti-leishmanial activity against intramacrophage amastigotes of Leishmania donovani., Conclusions: Tween 20 is a surfactant approved by the US FDA as an additive in food and pharmaceutical preparations. Synthesis of drug conjugates with surfactants such as Tween-20 could open up new opportunities to improve the solubility of many drugs, reduce their toxicity and could possibly target the brain as polysorbates known to facilitate nanoparticulate systems to cross the blood-brain barrier., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.)

Supramolecular macrocycles-based drug delivery systems are receiving wider recognition due to their self-assembly into nanostructures with unique characteristics. This study reports synthesis of resorcinarene-based novel and biocompatible amphiphilic supramolecular macrocycle that self-assembles into nano-vesicular system for Amphotericin B (Am-B) delivery, a model hydrophobic drug. The macrocycle was synthesized through a two-step reaction and was characterized with 1   H NMR and mass spectrometric techniques. Its biocompatibility was assessed in cancer cell lines, blood and animals. Its critical micelle concentration (CMC) was determined using UV spectrophotometer. Am-B loaded in novel macrocycle-based vesicles were examined according to their shape, size, surface charge, drug entrapment efficiency and excepients compatibility using atomic force microscope (AFM), Zetasizer, HPLC and FT-IR spectroscopy. Drug-loaded vesicles were also investigated for their in-vitro release, stability and in-vivo oral bioavailability in rabbits. The macrocycle was found to be nontoxic against cancer cells, haemo-compatible and safe in mice and revealed lower CMC. It formed mono-dispersed spherical shape vesicles of 174.4 ± 3.78 nm in mean size. Vesicles entrapped 92.05 ± 4.39% drug and were stable upon storage with gastric-simulated fluid and increased the drug oral bioavailability in rabbits. Results confirmed novel macrocycle as biocompatible vesicular nanocarrier for enhancing the oral bioavailability of lipophilic drugs.

Cryptococcosis is a fungal disease of global significance for which new effective treatments are needed. The conjugation of the synthetic antimicrobial peptide fragment UBI 31-38 to a coumarin derivative showed to be an effective approach for the design of a novel anticryptococcal agent. In addition to antifungal activity, the conjugate exhibited intense fluorescence, which could be valuable for mechanistic investigations of this molecule. In this work, we studied the photophysical properties of the conjugate and confocal scanning laser microscopy was used to inspect the distribution of the peptide-coumarin conjugate in Cryptococcus cell. The synergism of this compound with amphotericin B or fluconazole against C. gattii and C. neoformans strains was also investigated. The results indicated that the fluorescent conjugate alone as well as its combination with amphotericin B are promising tools against cryptococcosis., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.)

Objective: In this study, bovine serum albumin (BSA) nanoparticles coated with polysorbate- 80 (PS-80) and containing amphotericin B (AmB) were developed using a coacervation method., Methods: The nanoparticles were spherical, had a uniform size distribution (polydispersity < 0.25), a small mean size (185 ± 5 nm), a high zeta potential (-38.0 ± 0.7 mV), and a high AmB encapsulation efficiency (93 ± 1%). The AmB release profile was prolonged and diffusion-controlled, resulting in a low degree of AmB aggregation in solution. The physicochemical characteristics of these AmB containing nanoparticles were evaluated by X-ray diffraction, Fourier transform infrared spectroscopy, differential scanning calorimetry, and derivative thermogravimetry and showed that the nanoencapsulation process lead to AmB amorphization while maintaining its chemical integrity., Results: In a hemolysis assay, AmB-loaded PS-80-coated BSA nanoparticles demonstrated an absence of cytotoxicity toward erythrocytes, whereas pure and commercial AmB were highly hemolytic., Conclusion: In an assay to assess antifungal activity against Cryptococcus neoformans, AmB-charged PS-80-coated BSA nanoparticles were effective, however, due to the prolonged AmB release from the nanoparticles, the MIC was higher than for pure or commercial AmB. PS-80-coated BSA nanoparticles are potential carriers for the delivery of AmB for the treatment of Cryptococcus sp infections., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.)

Infectious diseases are the leading cause of morbidity and mortality, killing more than 15 million people worldwide. This is despite our advances in antimicrobial chemotherapy and supportive care. Nanoparticles offer a promising technology to enhance drug efficacy and formation of effective vehicles for drug delivery. Here, we conjugated amphotericin B, nystatin (macrocyclic polyenes), and fluconazole (azole) with silver nanoparticles. Silver-conjugated drugs were synthesized successfully and characterized by ultraviolet-visible spectrophotometry, Fourier transform infrared spectroscopy, and atomic force microscopy. Conjugated and unconjugated drugs were tested against Acanthamoeba castellanii belonging to the T4 genotype using amoebicidal assay and host cell cytotoxicity assay. Viability assays revealed that silver nanoparticles conjugated with amphotericin B (Amp-AgNPs) and nystatin (Nys-AgNPs) exhibited significant antiamoebic properties compared with drugs alone or AgNPs alone (P < 0.05) as determined by Trypan blue exclusion assay. In contrast, conjugation of fluconazole with AgNPs had limited effect on its antiamoebic properties. Notably, AgNP-coated drugs inhibited amoebae-mediated host cell cytotoxicity as determined by measuring lactate dehydrogenase release. Overall, here we present the development of a new formulation of more effective antiamoebic agents based on AgNPs coated with drugs that hold promise for future applications.

Aggregation of α-synuclein (α-Syn) into toxic oligomers and fibrils leads to Parkinson's disease (PD) pathogenesis. Molecules that can inhibit the fibrillization and oligomerization of α-Syn have potential therapeutic value. Here, we studied four selective amyloid inhibitors: dopamine (Dopa), amphotericin-B (Amph), epigallocatechingallate (EGCG), and quinacrinedihydrochloride (Quin) for their effect on oligomerization, fibrillization, and preformed fibrils of α-Syn. The aggregation kinetics of α-Syn using ThT fluorescence and conformational transition by circular dichroism (CD) in the presence and absence of these four compounds suggest that, except Quin, the remaining three molecules inhibit α-Syn aggregation in a concentration dependent manner. Consistent with the aggregation kinetics data, the morphological study of aggregates formed in the presence of these compounds showed corresponding decrease in fibrillar size. The analysis of cell viability using MTT assay showed reduction in toxicity of α-Syn aggregates formed in the presence of these compounds, which also correlates with reduction of exposed hydrophobic surface as studied by ANS binding. Additionally, these inhibitors, except Quin, demonstrated reduction in size as well as the toxicity of oligomeric/fibrillar aggregates of α-Syn. The residue specific interaction to low molecular weight (LMW) species of α-Syn by 2D NMR study revealed that, the region and extent of binding are different for all these molecules. Furthermore, fibril-binding data using SPR suggested that there is no direct relationship between the binding affinity and fibril inhibition by these compounds. The present study suggests that sequence based interaction of small molecules with soluble α-Syn might dictate their inhibition or modulation capacity, which might be helpful in designing modulators of α-Syn aggregation.

This study presents the mode of interaction, structural features, and micellization of amphotericin B (AmB) with sodium deoxycholate sulfate (SDCS) as small lipid molecule at different ratios, as revealed by molecular docking simulations and nuclear magnetic resonance (NMR). AmB-SDCS micelles were synthesized by single pot rinsing method. Solid-state 13 C NMR revealed hydrogen (H)-bonding as the main interaction, occurring at different positions between AmB and SDCS at various ratios. Molecular docking elucidated that AmB-SDCS complex was stabilized by multiple H-bonds and van der Waals forces between SDCS and AmB. SDCS molecules wrap around the AmB in a head-to-tail fashion into a nanomicellar structure. AmB-SDCS micelles were stable after freeze-drying and presented zeta potential values between -27.5 and -42.6 mV and particle size in the range of 63.9 to 203.1 nm, upon rehydration in water. Hematological toxicity of AmB was controlled by exposure versus release of drug from SDCS micelles and concentration of SDCS to envelop the drug. Hemolysis of human erythrocytes was significantly reduced as compared to market formulation Fungizone ® and pure AmB. This study explained the chemical interaction of micellization of AmB in lipids, which can have greater implications in designing toxicologically safe formulations of hydrophobic drugs., (Copyright © 2017 American Pharmacists Association®. Published by Elsevier Inc. All rights reserved.)

Lipid nanoparticles are stable, biodegradable and biocompatible carriers offering excellent therapeutic efficacy. Here, a novel effort has been made to develop Miltefosine (HePC- hexadecylphosphocholine) stabilized chitosan anchored nanostructured lipid carriers (NLC) of Amphotericin B (AmB) as co-delivery vehicle to enhance killing of L. donovani. The entrapment efficiency of AmB was achieved upto 85.3% for HePC-AmB-CNLCs with mean particle size of 150.8±8.4nm, and zeta potential value of +28.2±1.1mV, respectively. The cumulative amount of AmB released at even after the 24h was less than 65% from HePC-AmB-CNLCs and Tween-80-AmB-CNLCs. Intravenous administration of HePC-AmB-CNLCs revealed the significantly increased localization of AmB in both liver and spleen when estimated. FACS study represented enhanced uptake of FITC-HePC-CNLCs over FITC-HePC-NLCs in J774A.1 cell lines. Highly significant in vitro and in vivo anti-leishmanial activity (p<0.05 compared with Tween 80-AmB-CNLCs) was observed with HePC-AmB-CNLCs when tested against VL in Leishmania donovani-infected hamsters. The haemolysis and cytotoxicity studies showed the safety of HePC-AmB-CNLCs and Tween 80-AmB-CNLCs. The findings suggested that it would be preferable to deliver AmB through HePC stabilized chitosan anchored nanostructured lipid carriers for rapid and effective treatment with decreased adverse effects., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Background: Several chemical modifications have been developed to overcome the toxicity of amphotericin B (AmB). Oxidized forms of AmB (AmB-ox), which may occur in patient's circulation during therapy, are as toxic as AmB. Complexes with copper (II) ions (AmB-Cu 2+ ) have been reported to be less toxic to human cells. Previous studies showed that AmB changed the expression of transforming growth factor-beta (TGF-β). Therefore, the objective of this study was to investigate the influence of AmB and its modified forms on the expression of genes encoding for TGF-β family members and related proteins in renal cells., Methods: Human renal proximal tubule cells (RPTEC) were treated with AmB-Cu 2+ , AmB, or the oxidized form AmB-ox. The expression of TGF-β family members and related genes was determined using oligonucleotide microarrays. TGF-β1 protein level was determined using ELISA method. The mRNA level of TGF-β isoforms, TGF-β receptors and differentiating genes was evaluated by real-time RT-qPCR., Results: AmB-Cu 2+ increased the mRNA levels of TGF-β1 and TGF-β2 isoforms and two genes encoding receptors: TGFBR1 and TGFBR2. TGF-β1 protein level in culture medium was not increased after stimulation with AmB-Cu 2+ . Microarray analysis revealed changes in both pro-fibrotic and anti-fibrotic genes., Conclusions: These results suggest that AmB-Cu 2+ may induce repair mechanisms in renal proximal tubule cells via changes in the expression of genes involved in intracellular signaling., (Copyright © 2017 Institute of Pharmacology, Polish Academy of Sciences. Published by Elsevier Urban & Partner Sp. z o.o. All rights reserved.)

The goal of study was to develop micellar formulation of Amphotericin B (AmB) to improve its antileishmanial efficacy. AmB loaded pluronic F127 (PF 127) micelles were developed and coated with chitosan (Cs-PF-AmB-M) to accord immunoadjuvant and macrophage targeting properties. Hemolysis and cytotoxicity studies demonstrated that Cs-PF-AmB-M was 7.93 fold (at 20μg/ml AmB concentration) and 9.35 fold less hemolytic and cytotoxic, respectively in comparison to AmB suspension. Flow cytometry studies indicated that Cs-PF-FITC-M was 21.97 fold higher internalized byJ774A.1 macrophage in comparison to PF-FITC-M.Cs-PF-AmB-M showed excellent in-vitro (1.82 fold in compared to AmB suspension) and in-vivo (75.84±7.91% parasitic inhibition) antileishmanial activity against macrophage resident intracellular promastigotes and Leishmania donovani infected Syrian hamsters, respectively. Chitosan coating stimulated a Th1 immune response mediating auxiliary immunotherapeutic action as judged by in-vitro and in-vivo cytokine and mRNA expression. Toxicity studies demonstrated normal blood urea nitrogen (BUN) and plasma creatinine (PC) level and no sign of abnormal histopathology upon intravenous administration of micellar formulations. Pharmacokinetic profiling and tissue distribution studies indicated that AmB was preferentially localized in macrophage harboring tissue instead of kidney, thereby circumventing the characteristic nephrotoxicity. Conclusively, Cs-PF-AmB-M could be a viable alternative for the current immuno and chemotherapy of visceral leishmaniasis (VL)., (Copyright © 2017 Elsevier B.V. All rights reserved.)

A series of amides of the antifungal antibiotic amphotericin B (AmB) and its conjugates with benzoxaboroles was tested to determine whether they form pores in lipid bilayers and to compare their channel characteristics. The tested derivatives produced pores of larger amplitude and shorter lifetime than those of the parent antibiotic. The pore conductance was related to changes in the partial charge of the hydrogens of the hydroxyl groups in the lactone ring that determined the anion coordination in the channel. Neutralization of one of the polar group charges in the AmB head during chemical modification produced a pronounced effect by diminishing the dwell time of the polyene channel compared to modification of both groups. In this study, compounds that had a modification of one carboxyl or amino group were less effective in initializing phase separation in POPC-membranes compared to derivatives that had modifications of both polar groups as well as the parent antibiotic. The effects were attributed to the restriction of the aggregation process by electrical repulsion between charged derivatives in contrast to neutral compounds. The significant correlation between the ability of derivatives to increase the permeability of model membranes-causing the appearance of single channels in lipid bilayers or inducing calcein leakage from unilamellar vesicles-and the minimal inhibitory concentration indicated that the antifungal effect of the conjugates was due to pore formation in the membranes of target cells.

Amphotericin B (AmB) remains the "gold standard" for systemic antifungal therapy, even though new drugs are emerging as the attractive antifungal agents. Since AmB has negligible oral absorption as a consequence of its unfavorable physicochemical characterizations, its use is restricted to parenteral administration which is accompanied by severe side effects. As greater understanding of the gastrointestinal tract has developed, the advanced drug delivery systems are emerging with the potential to overcome the barriers of AmB oral delivery. Much research has demonstrated that oral AmB formulations such as lipid formulations may have beneficial therapeutic efficacy with reduced adverse effects and suitable for clinical application. Here we reviewed the different formulation strategies to enhance oral drug efficacy, and discussed the current trends and future perspectives for AmB oral administration in the treatment of antifungal infections.

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.

Aerosolized liposomal amphotericin B (L-AmB) has been investigated as prophylaxis against invasive aspergillosis. However, the clinical results are controversial and some trials suggest that toxicity could be a limitation for wider use. Our aim was to assess the dynamics of cell toxicity induced in a human alveolar epithelial cell line (A549) after exposure to L-AmB (50 to 400μg/ml) or amphotericin B deoxycholate (D-AmB; 50 to 200μg/ml) by monitoring real-time A549 cell viability using an impedance-based technology. Results were expressed as cell index values integrating cell adhesion, proliferation, and survival. In parallel, the gene expression of proinflammatory cytokines was quantified at 6 and 24h after drug addition by real-time RT-PCR on cell lysates. No sustained reduction of cell indexes was observed with L-AmB or empty liposomes, even at 400μg/ml. Only the highest concentration tested of L-AmB (400μg/ml) yielded transient significant 6-fold and 4-fold induction of TNF-α and IL-8 mRNAs, respectively. In contrast, D-AmB induced a decrease in cell indexes and only the 50μg/ml concentration of D-AmB was followed by cell recovery, higher concentrations leading to cell death. Significant 4-fold, 7-fold and 3-fold inductions of TNF-α, IL-8 and IL-33 mRNAs were also observed at 6h with 50μg/ml of D-AmB. In conclusion, continuous cell impedance measurement showed no toxicity on overall cellular behavior although a slight proinflammatory cytokine expression is possible after L-AmB challenge. Real-time kinetics of cell impedance is an interesting tool for initial screening of cell toxicity., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Background: Hypophosphatemia is commonly observed in critically ill patients. Inorganic phosphorus is quantified by spectrophotometric measurement of a phosphomolybdate complex, a method with multiple documented interferents. Our clinical laboratory was contacted to investigate a case of asymptomatic hypophosphatemia in a patient receiving high-dose liposomal amphotericin B therapy (L-AMB)., Methods: In vitro experiments were performed by spiking L-AMB into residual plasma specimens. Phosphate was measured on the Beckman Coulter AU and Ortho Diagnostics Vitros instruments., Results: When measured on the AU, phosphate in plasma with approximately 250mcg/mL of L-AMB demonstrated a median negative bias of 3.45mg/dL relative to unspiked samples. In contrast, Vitros phosphate measurements demonstrated excellent agreement for specimens with and without L-AMB (median bias -0.2mg/dL)., Conclusions: High L-AMB concentrations induced a significant negative bias on phosphate measured by the AU assay, but did not affect the Vitros assay. Laboratorians and clinicians should be aware of this phenomenon in patients receiving L-AMB who develop unexplained hypophosphatemia., (Copyright © 2017 The Canadian Society of Clinical Chemists. Published by Elsevier Inc. All rights reserved.)

We compared the potency of four derivatives of the antimicrobial peptide halictine-2 against six Candida species. Observed activity was peptide and species specific. Halictines rapidly permeabilized cell membranes and caused the leakage of cytosolic components. Their killing potential was enhanced by the commercial antimicrobial agent octenidine dihydrochloride. The effect on C. glabrata cells did not depend on the activity of Cdr pumps, but was influenced by their lipid composition. The pre-treatment of cells with myriocin, an inhibitor of sphingolipid synthesis, enhanced the peptides' activity, whereas pre-treatment with terbinafine and fluconazole, inhibitors of sterol synthesis, significantly weakened their efficacy. The killing efficacy of peptides increased in combination with amphotericin B. Thus the mode of action of halictines is likely to depend on the plasma-membrane sterols, which might explain the observed differences among the tested Candida species., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Aim: Gallic acid and its ester derivatives have shown antifungal activity in vitro. This study was performed to investigate their activity against Candida albicans and their toxicity in the animal models Caenorhabditis elegans and zebrafish embryos., Results: The compounds protected worms from C. albicans infection. The dodecyl gallate was the most effective. In zebrafish embryo, gallic acid and dodecyl gallate were the least toxic., Conclusion: Gallic acid and its ester derivatives have potential for in vivo use against C. albicans infection. The antifungal effects and toxicity of gallate esters in these alternative animal models were dependent on carbon chain length.

Biomimetic synthesis of nanoparticles offers a convenient and bio friendly approach to fabricate complex structures with sub-nanometer precision from simple precursor components. In the present study, we have synthesized nanoparticles of Amphotericin B (AmB), a potent antifungal agent, using Aloe vera leaf extract. The synthesis of AmB nano-assemblies (AmB-NAs) was established employing spectro-photometric and electron microscopic studies, while their crystalline nature was established by X-ray diffraction. AmB-nano-formulation showed much higher stability in both phosphate buffer saline and serum and exhibit sustained release of parent drug over an extended time period. The as-synthesized AmB-NA possessed significantly less haemolysis as well as nephrotoxicity in the host at par with Ambisome ® , a liposomized AmB formulation. Interestingly, the AmB-NAs were more effective in killing various fungal pathogens including Candida spp. and evoked less drug related toxic manifestations in the host as compared to free form of the drug. The data of the present study suggest that biomimetically synthesized AmB-NA circumvent toxicity issues and offer a promising approach to eliminate systemic fungal infections in Balb/C mice.

Conventional chemotherapy for leishmaniasis includes considerably toxic drugs and reports of drug-resistance are not uncommon. Liposomal encapsulated drugs appear as an option for the treatment of leishmaniasis, providing greater efficacy for the active and reducing its side effects by promoting superior tissue absorption, favouring drug penetration into the macrophages, and retarding its clearance from the site of action. In this paper, a review on the advances achieved with liposome-based anti-leishmaniasis drug delivery systems is presented. Formulations prepared with either conventional or modified (sugar-coated, cationic, niosomes, peptides- and antibodies-bounded) liposomes for the delivery of pentavalent antimonials, amphotericin B, pentamidine, paromomycyn, and miltefosine were covered. This literature review depicts a scenario of no effective therapeutic agents for the treatment of this neglected disease, where liposomal formulations appear to improve the effectiveness of the available antileishmania agents.

Leishmania mexicana infection causes localized skin lesions that can lead to tissue damage and permanent disfigurement if not resolved. Currently, recommended treatments include intravenous administration of Amphotericin B, which is undesirable due to the associated cost and patient burden related to receiving regular injections. In this study, we evaluated the effect of topical treatment with a nanoliposomal formulation of Amphotericin B that is penetrable to the skin (SinaAmphoLeish 0.4%) in mice infected with L. mexicana by using ulcerated (BALB/c) and non-ulcerated (129SVE) models. BALB/c mice received a 4 week treatment following ulcerated lesion development, while 129SVE mice received a 10 week treatment beginning at week 5 post-infection. Although mice from both models showed comparable susceptibility to L. mexicana infection after topical treatment with SinaAmphoLeish relative to controls, 129SVE mice displayed a transient decrease in lesion sizes which eventually became similar to control mice. On other hand this treatment resulted in no reduction in the lesion sizes in BALB/c mice. 129SVE treated mice exhibited greater IFN-γ, IL-4, and IL-10 cytokine levels and higher T-cell proliferation in re-stimulated draining lymph node cells. BALB/c mice showed no differences in cytokine responses between treated and control mice. These findings indicate that topical SinaAmphoLeish treatment is not likely to be effective in the treatment of cutaneous leishmaniasis caused by L. mexicana., (Copyright © 2017. Published by Elsevier B.V.)

Amphotericin B (AmB) is still the most effective drug for the treatment of systemic fungal infections in humans. Despite significant theoretical and experimental efforts trying to understand its molecular mechanism of action, the answer has remained elusive. In this work, we present a computational methodology to test the current membrane related hypotheses, namely, transmembrane ion channel, adsorption, and sterol sponge. We use a thermodynamic approach in which we represent the membrane by a multiphase solvation model with atomic detail (MMPSM) and calculate the free energy of transferring the drug between phases with different dielectric properties. Furthermore, we compare AmB to a chemical analogue with increased safety, an l-histidine methyl ester of AmB. Our findings reveal that both drugs dimerize in all solvents studied here. Also, it is energetically unfavorable for the drugs to penetrate into the hydrophobic core of the membrane, unless their concentration is high. Finally, it is thermodynamically possible that the sterols migrate from the membrane into a drug droplet adsorbed at the surface of the bilayer. In light of our results, several effects could take place in the complex antibiotic process. We suggest a molecular mechanism that connects all three hypotheses through a drug concentration dependence and propose that the drug promotes the formation of membrane toroidal pores. Because MMPSM is of general interest, we made it available at http://tripplab.com/tools/mmpsm .

The aim of this study was to compare the biopharmaceutical characteristics and irritation potentials of microemulsions (MEs) and conventional systems (CSs) containing oil from Syagrus cearensis for topical delivery of Amphotericin B (AmB). Pseudo-ternary phase diagrams were constructed using a water titration method to develop the MEs, and the CSs were prepared according to the classical technique of phase inversion. In the skin permeation and retention study, dermatomed pig skin without stratum corneum was used as an alternative disturbed skin model. The irritation potential was evaluated using three different methods, chorioallantoic membrane assays (HET-CAM and CAM-TBS), and bovine corneal opacity and permeability (BCOP) test. The optimized formulation (ME1) consisting of 0.1% (w/w) Amphotericin B, 9.1% (w/w) catolé oil, 81% (w/w) Smix (1:1, Tween 20 and Kolliphor EL) possessed droplet size of 31.02 ± 0.9 nm, zeta potential of -23.4 mV, and viscosity 0.63 ± 0.1 Pa.s. ME1 exhibited greater retention of AmB in to skin layers (84.79 ± 2.08 μg cm -2 ) than all the others formulations. In general, MEs showed higher drug release and retention than CSs and all of the formulations showed greater retentivity than permeability. Only MEs developed using Labrasol/Plurol Oleique (L/PO) as the surfactant and co-surfactant exhibited a moderate irritation potential; all other MEs and CSs were classified as non-irritants or slight irritants. The results indicate that formulations containing oil from S. cearensis are promising alternatives for the delivery of AmB targeting the treatment of cutaneous leishmaniasis.

Amphotericin B (AmB) has been widely used against fungal infections throughout almost the entire body, including the skin, nails, oral cavity, respiratory tract, and urinary tract. However, the development of AmB-loaded nanoparticles demands a novel technique that reduces its toxicity and other associated problems. Here, we developed a pH-responsive and redox-sensitive polymer-based AmB-delivery carrier system. In particular, this system was functionalized by conjugation with the antifungal peptide histatin 5, which acts both as a targeting ligand and a synergistic antifungal molecule against Candida albicans, a major systemic fungal pathogen of humans. Our results in vitro and in vivo suggest that this drug-delivery system may serve as a novel tool to facilitate the use of antimicrobial peptides as targeting ligands to pathogenic microbes, which would open new avenues of investigation in the field of drug delivery., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Fatal Candida albicans infections in the mucosal system can occur in association with immune-compromised diseases and dysbacteriosis. Currently, amphotericin B (AmB) is considered to be the most effective antibiotic in the treatment of C. albicans infections, but its clinical application is limited by side effects and poor bioavailability. In order to use AmB in the local treatment of oral C. albicans infections, AmB/MPEG-PCL-g-PEI (monomethoxy poly(ethylene glycol)-poly(epsilon-caprolactone)-graft-polyethylenimine, MPP) micelles were prepared. A series of characterizations were performed. The micelles allowed a sustained in vitro release in both normal oral conditions (pH 6.8) and C. albicans infection conditions (pH 5.8). Then, buccal tablets containing freeze-dried powder of AmB/MPP micelles were produced by direct compression process and evaluated as regards to weight variation, hardness, and friability. In vitro drug release of the buccal tablets was measured in both the United States Pharmacopeia dissolution apparatus and the dissolution rate test apparatus, which was previously designed for simulating in vivo conditions of the oral cavity. The buccal tablets could sustainably release within 8 h and meet the antifungal requirements. Regarding safety assessment of AmB/MPP micelles, in vivo histopathological data showed no irritation toward buccal mucosa of the rats in both optical microscopy and ultrastructure observation of the tissues. MTT experiment proved that AmB/MPP micelles reduced the cytotoxicity of AmB. The micelles delivered through the gastrointestinal route were also found to be non-systemic toxicity by liquid chromatography-mass spectrometry analysis. Furthermore, the antifungal action of AmB/MPP micelles was evaluated. Although AmB/MPP had no obvious improvement as compared to AmB alone in the antifungal effect on planktonic C. albicans , the micelles significantly enhanced the antifungal activity against the biofilm state of C. albicans . Thus, it was concluded that AmB/MPP micelles represent a promising novel drug delivery system for the local treatment of oral C. albicans infections., Competing Interests: Disclosure The authors report no conflicts of interest in this work.

The purpose of this paper was to investigate the aggregation of amphotericin B (AMB) and AMB-arabinogalactan conjugate (AMB-AGC), and the interactions of these drugs with free and membrane-embedded sterols. Aggregation of AMB and AMB-AGC was studied by circular dichroic (CD) and UV absorbance spectroscopic techniques. The effect of liposomes on the spectra was utilized to investigate the interactions of aggregates with membrane-embedded sterols. Interaction with free sterols was studied by measuring sterols' effect on AMB/AMB-AGC susceptibility test. The results demonstrated that AMB-AGC forms unique aggregates in aqueous solution which differ from those formed by free AMB. Ergosterol and cholesterol embedded in liposomes, affected the CD spectra obtained for both AMB and AMB-AGC, indicating interactions of these sterols with both drugs. Interaction with both cholesterol and ergosterol resulted in an increase of AMB-AGC's minimal inhibitory concentration (MIC) in Candida albicans. In conclusion, AMB-AGC forms unique aggregates in aqueous solution; these aggregates interact with membrane-embedded cholesterol and ergosterol and with free sterols. These results indicate that the selectivity of AMB-AGC to fungal cells may not occur due to inability to bind cholesterol but probably as a result of this unique aggregation. Understanding this mechanism may help to develop a safer AMB formulation for therapy., (© The Author 2016. Published by Oxford University Press on behalf of The International Society for Human and Animal Mycology. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Polyene macrolides such as nystatin A1 and amphotericin B have been known to be potent antifungal antibiotics for several decades. Because the therapeutic application of polyenes is restricted by severe side effects such as nephrotoxicity, various chemical and biological studies to modify the polyene structure have been conducted to develop less-toxic polyene antifungals. A newly discovered nystatin-like polyene compound NPP was shown to contain an aglycone that was identical to nystatin but harbored a unique di-sugar moiety, mycosaminyl-N-acetyl-glucosamine, which led to higher solubility and reduced hemolytic toxicity. Additionally, a NPP-specific second sugar extending gene, nppY, was recently identified to be responsible for the transfer of a second sugar, N-acetyl-glucosamine, in NPP biosynthesis. In this study, we investigated biosynthesis of the glycoengineered NPP analog through genetic manipulation of the NPP A1 producer, Pseudonocardia autotrophica KCTC9441. NypY is another second sugar glycosyltransferase produced by Pseudonocardia sp. P1 that is responsible for the transfer of a mannose to the mycosaminyl sugar residue of nystatin. We blocked the transfer of a second sugar through nppY disruption, then expressed nypY in P. autotrophica △nppY mutant strain. When compared with nystain A1 and NPP A1, the newly engineered mannosylated NPP analog showed reduced in vitro antifungal activity, while exhibiting higher nephrotoxical activities against human hepatocytes. These results suggest for the first time that not only the number of sugar residues but also the type of extended second sugar moiety could affect biological activities of polyene macrolides.

Visceral leishmaniasis, a protozoan disease transmitted by phlebotomine sandflies which affect mostly in Indian sub-continent. The treatment for visceral leishmaniasis (VL) caused by Leishmania donovani are limited and unsatisfactory. Currently available drug against such as miltefosine and polymer based drugs amBisome has high efficacy against VL but found serious side effects and poor absorbance. To overcome this, we developed peptide (glycine) coated iron oxide (Fe 3 O 4) nanoparticles (GINPs) encapsulated amphoterecin B (AmB) drug against visceral leishmaniasis. Synthesis of GINPs was carried out and different characterization technique used to confirm the synthesis and size of GINPs GINPs-AmB showed that particle size in the range of 10-15nm and closed to spherical in shaped. GINPs-AmB showed release rate of AmB is higher at lower pH. Significantly two fold higher efficacies of GINP encapsulated AmB during in vitro study. There was a substantial reduction in the total parasite burden in spleen in treated groups (GINPs encapsulate AmB), compare to AmB alone. The results obtained from this study revealed that AmB loaded GINPs is twofold effective than AmB and therefore, it opens a new avenue for use of AmB loaded GINPs against VL., (Copyright © 2017 Elsevier B.V. All rights reserved.)

During an investigation of the chemistry of the endophytic actinobacterium Streptomyces albospinus RLe7, which was isolated from the roots of the Brazilian medicinal plant Lychnophora ericoides, three new natural products, (2R*,4S*)-2-((1'S*)-hydroxy-4'-methylpentyl)-4-(hydroxymethyl)butanolide (1), (3R*,4S*,5R*,6S*)-tetrahydro-4-hydroxy-3,5,6-trimethyl-2-pyranone (2), and 1-O-(phenylacetyl)glycerol (3), together with known secondary metabolites (S)-4-benzyl-3-oxo-3,4-dihydro-1H-pyrrolo[2,1-c][1,4]oxazine-6-carbaldehyde (4), (S)-4-isobutyl-3-oxo-3,4-dihydro-1H-pyrrolo[2,1-c][1,4]oxazine-6-carbaldehyde (5), and the diketopiperazines cyclo(l-Tyr-l-Pro) (6) and cyclo(l-Val-l-Pro) (7), were isolated. The role of isolated natural products in the interaction between S. albospinus RLe7 and the fungus Coniochaeta sp. FLe4, an endophyte from the same plant, was investigated. None of these isolated actinobacterial compounds were able to inhibit the fungus or induce the fungal red pigmentation observed when both endophytes interact. Further investigation using mass spectrometry approaches enabled identifying the well-known antifungal compound amphotericin B (9) as a microbial metabolite of S. albospinus RLe7. Finally, compound 9 was demonstrated as at least one of the agents responsible for both the antifungal activity and induction of red-pigmented fungal phenotype.

Amphotericin B is an antifungal drug widely used in Intensive Care Units. Therapeutic drug monitoring (TDM) of amphotericin B is recommended for the assessment of toxicity surveillance and treatment optimization. In this paper we described the development and validation of a new Ultra High Performance Liquid Chromatography coupled to Diode Array Detection (UHPLC-DAD) method for the quantification of Amphotericin B in 200μL human plasma over a wide range of concentrations (0.125-10mg/L). The new method has been validated following international guidelines on bioanalytical method validation and showed high selectivity, high accuracy and precision and high process efficiency. The new UHPLC-DAD method that we describe is robust, rapid, cost effective and suitable for application to the routine TDM analyses., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Exogenous drug as an antidote to treat various infections get absorbed in the blood circulatory system of a human can directly contact with transporter proteins such as serum albumin. Therefore, for rational drug discovery, understanding the biomolecular interaction between drugs and protein is highly important. In this contribution, we describe the possible interactions between an antifungal drug Amphotericin B (AmB) and Bovine Serum Albumin (BSA) using multi-spectroscopic techniques and further confirmed through in-silico approaches. Binding effects of AmB on BSA conformation, surface morphology, topology, and stability were determined by Ultraviolet-visible spectroscopy (UV), Fourier transform infrared spectroscopy (FT-IR), Circular Dichroism (CD), Transmission Electron Microscopy (TEM), Dynamic Light Scattering (DLS), Fluorescence Spectroscopy and Molecular dynamic simulations. The Stern-Volmer equation was used to determine the binding site (0.4) and binding constant (8.16×10 5 M -1 ). The intrinsic intensity of the native BSA was quenched by AmB through static quenching mechanism. The calculated Gibbs free energy value (-8.70kcal/mol) indicated the involvement of hydrogen bonding and hydrophobic contacts in BSA-AmB interaction. The hydrodynamic radii and surface contact area of BSA-AmB molecules are decreasing which can strongly support the stabilizing action of complex particles. Moreover, the finding of this work will provide information for the drug designers to further study the AmB binding mechanism and their pharmacodynamics and pharmacokinetics features in order to achieve better therapeutic efficacy., (Copyright © 2017. Published by Elsevier B.V.)

Purpose: The aim of this work is to design new chitosan conjugates able to self-organize in aqueous solution in the form of micrometer-size platelets. When mixed with amphotericin B deoxycholate (AmB-DOC), micro-platelets act as a drug booster allowing further improvement in AmB-DOC anti-Candida albicans activity., Methods: Micro-platelets were obtained by mixing oleoyl chitosan and α-cyclodextrin in water. The formulation is specifically-engineered for mucosal application by dispersing chitosan micro-platelets into thermosensitive pluronic ® F127 20 wt% hydrogel., Results: The formulation completely cured C. albicans vaginal infection in mice and had a superior activity in comparison with AmB-DOC without addition of chitosan micro-platelets. In vitro studies showed that the platelets significantly enhance AmB-DOC antifungal activity since the IC 50 and the MIC 90 decrease 4.5 and 4.8-times. Calculation of fractional inhibitory concentration index (FICI = 0.198) showed that chitosan micro-platelets act in a synergistic way with AmB-DOC against C. albicans. No synergy is found between spherical nanoparticles composed poly(isobutylcyanoacrylate)/chitosan and AmB-DOC., Conclusion: These results demonstrate for the first time the ability of flattened chitosan micro-platelets to have synergistic activity with AmB-DOC against C. albicans candidiasis and highlight the importance of rheological and mucoadhesive behaviors of hydrogels in the efficacy of the treatment.

Several biologically relevant phospholipids are considered as potential excipients for IV administration liposome's formulation of AMB (Biopharmaceututics Classification System Class IV). On the basis of in vivo bioavaibility studies, DMPC and DMPG were ranked as the first potent encapsulation enhancers for this model drug, especially if one expects to target DMPG rich systems as pulmonary surfactant. Subsequently, dispersions (multilayers) of DMPC, DMPG or in binary systems with various molar ratios were prepared with or without AMB (molar ratios AMB/lipid) and further investigated using the 1 H-, 31 P-NMR methods. It was found that equimolar preparations of DMPG/DMPG exhibited both a good encapsulation of AMB, while also probably able to target pulmonary surfactant. Besides DMPG did not exhibit the same solubilization properties. Conversely, no targeting by DMPC dispersion alone was expected, even if a good solubilization was obtained., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Chagas disease (CD) is a parasitic zoonosis endemic in most mainland countries of Central and South America affecting nearly 10 million people, with 100 million people at high risk of contracting the disease. Treatment is only effective if received at the early stages of the disease. Only two drugs (benznidazole and nifurtimox) have so far been marketed, and both share various limitations such as variable efficacy, many side effects, and long duration of treatment, thus reducing compliance. The in vitro and in vivo efficacy of poly-aggregated amphotericin B (AmB), encapsulated poly-aggregated AmB in albumin microspheres (AmB-AME), and dimeric AmB-sodium deoxycholate micelles (AmB-NaDC) was evaluated. Dimeric AmB-NaDC exhibited a promising selectivity index (SI = 3164) against amastigotes, which was much higher than those obtained for licensed drugs (benznidazole and nifurtimox). AmB-AME, but not AmB-NaDC, significantly reduced the parasitemia levels (3.6-fold) in comparison to the control group after parenteral administration at day 7 postinfection. However, the oral administration of AmB-NaDC (10-15 mg/kg/day for 10 days) resulted in a 75% reduction of parasitemia levels and prolonged the survival rate in 100% of the tested animals. Thus, the results presented here illustrate for the first time the oral efficacy of AmB in the treatment of trypanosomiasis. AmB-NaDC is an easily scalable, affordable formulation prepared from GRAS excipients, enabling treatment access worldwide, and therefore it can be regarded as a promising therapy for trypanosomiasis.

Surface modification of liposomes with targeting ligands is known to improve the efficacy with reduced untoward effects in treating infective diseases like visceral leishmaniasis (VL). In the present study, modified ligand (ML), designed by modifying polysaccharide with a long chain lipid was incorporated in liposomes with the objective to target amphotericin B (Amp B) to reticuloendothelial system and macrophages. Conventional liposomes (CL) and surface modified liposomes (SML) were characterized for size, shape, and entrapment efficiency (E.E.). Amp B SML with 3% w/w of ML retained the vesicular nature with particle size of ∼205 nm, E.E. of ∼95% and good stability. SML showed increased cellular uptake in RAW 264.7 cells which could be attributed to receptor-mediated endocytosis. Compared to Amp B solution, Amp B liposomes exhibited tenfold increased safety in vitro in RAW 264.7 and J774A.1 cell lines. Pharmacokinetics and biodistribution studies revealed high t 1/2 , area under the curve (AUC) 0-24 , reduced clearance and prolonged retention in liver and spleen with Amp B SML compared to other formulations. In promastigote and amastigote models, Amp B SML showed enhanced performance with low 50% inhibitory concentration (IC 50 ) compared to Amp B solution and Amp B CL. Thus, due to the targeting ability of ML, SML has the potential to achieve enhanced efficacy in treating VL.

This study reports design and evaluation of chitosan-based microparticle activity against Candida glabrata in vitro and in vivo in immunocompetent mice model artificially maintained in oestrus state. Because their flattened shape, chitosan microparticles are called here micro-platelets. They were obtained by self-association of oleoyl chitosan and α-cyclodextrin in water. A mixture of amphotericin B-deoxycholate (Fungizone ® , AmB-DOC) and chitosan micro-platelets gelified with pluronic ® F127 (20wt%) completely cured C. glabrata vaginal infection. Colony factor unit counting and mycological analysis of mice vaginal mucosa after Grocott-Gomori methenamine-silver staining confirmed the absence of C. glabrata. Furthermore, in vitro evaluations revealed that IC 50 and MIC 90 of AmB-DOC were decreased 1.8 and 1.4-times respectively when associated with chitosan micro-platelets. Neither native chitosan nor oleoyl chitosan allowed improvement in AmB-DOC anti-C. glabrata activity. This work demonstrates for the first time that a simple mixing of chitosan micro-platelets with AmB-DOC enhanced its anti-C. glabrata activity., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Several polyene macrolides are potent antifungal agents that have severe side effects. Increased glycosylation of these compounds can improve water solubility and reduce toxicity. Three extending glycosyltransferases are known to add hexoses to the mycosaminyl sugar residues of polyenes. The Actinoplanes caeruleus PegA enzyme catalyses attachment of a D-mannosyl residue in a β-1,4 linkage to the mycosamine of the aromatic heptaene 67-121A to form 67-121C. NppY from Pseudonocardia autotrophica adds an N-acetyl-D-glucosamine to the mycosamine of 10-deoxynystatin. NypY from Pseudonocardia sp. P1 adds an extra hexose to a nystatin, but the identity of the sugar is unknown. Here, we express the nypY gene in Streptomyces nodosus amphL and show that NypY modifies 8-deoxyamphotericins more efficiently than C-8 hydroxylated forms. The modified heptaene was purified and shown to be mannosyl-8-deoxyamphotericin B. This had the same antifungal activity as amphotericin B but was slightly less haemolytic. Chemical modification of this new disaccharide polyene could give better antifungal antibiotics.

Background: A new form of amphotericin B (AmB)- complex with copper (II) ions (AmB-Cu 2+ ) - is less toxic to human renal cells. Cytokines, including Tumor Necrosis Factor (TNF), are responsible for nephrotoxicity observed in patients treated with AmB. Another problem during therapy is the occurrence of oxidized forms of AmB (AmB-ox) in patients' circulation. To elucidate the molecular mechanism responsible for the reduction of the toxicity of AmB-Cu 2+ , we evaluated the expression of genes encoding TNF and its receptors alongside encoding proteins involved in TNF-induced signalization., Methods: Renal cells (RPTECs) were treated with AmB, AmB-Cu 2+ or AmB-ox. The expression of TNF and its receptors was evaluated by ELISA tests and real-time RT-qPCR. The expression of TNF-related genes was appointed using oligonucleotide microarrays., Results: Only sTNFR1 was detected, and its level was lower in AmB-Cu 2+ - and AmB-ox-treated cells. TNFR1 mRNA was downregulated in AmB-ox, while TNFR2 mRNA was upregulated in AmB and AmB-Cu 2+ . Several changes in the expression of TNF-related genes coincided with changes in the expression of TNF receptors., Conclusions: The lower toxicity of AmB-Cu 2+ could result from the changes in the expression of TNF receptors, which coincided with the changes in the expression of genes encoding proteins involved in TNF-induced pathways. This situation might subsequently result in a changes in intracellular signalization and influence the toxicity of tested forms of AmB on renal cells., (Copyright © 2016. Published by Elsevier Urban & Partner Sp. z o.o.)

Oral delivery of pharmaceuticals requires that they retain their physical and chemical attributes during transit within the gastrointestinal (GI) tract, for the manifestation of desired therapeutic profiles. Solid lipid nanoparticles (SLNs) are used as carriers to improve the absorption of hydrophobic drugs. In this study, we examine the stability of amphotericin B (AmB) and paracetamol (PAR) SLNs in simulated GI fluids during gastric emptying. On contact with the simulated fluids, the particles increased in size due to ingress of the dissolution media into the particles. Simulated gastric emptying revealed that the formulations had mean sizes <350nm and neutral surface charges, both of which are optimal for intestinal absorption of SLNs. There was ingress of the fluids into the SLNs, followed by diffusion of the dissolved drug, whose rate depended on the solubility of the loaded-drug in the particular medium. Time-of-flight secondary ion mass spectrometry analyses indicated that drug loading followed the core-shell model and that the AmB SLNs have a more drug-enriched core than the PAR SLNs do. The AmB SLNs are therefore a very suitable carrier of AmB for oral delivery. The stability of the SLNs in the simulated GI media indicates their suitability for oral delivery., (Copyright © 2016. Published by Elsevier B.V.)

The AmB-Cu(II) complex has recently been reported as an antifungal agent with reduced aggregation of AmB in aqueous solutions, increased anti C. albicans activity and lower toxicity against human cells in vitro. In the present work, investigations of the activity of the AmB-Cu (II) complex against fungal pathogens with varying susceptibility, including C. albicans and C. parapsilosis strains and intrinsically resistant A. niger, and cytotoxicity in normal human dermal fibroblasts (NHDF) in vitro were performed. For better understanding of the mechanism of reduced cytotoxicity and increased fungicidal activity, the influence of the AmB-Cu (II) complex on membrane integrity and accumulation of cellular reactive oxygen species (ROS) and mitochondrial superoxide was compared with that of conventional AmB. In the sensitive C. albicans and C. parapsilosis strains, the AmB-Cu(II) complex showed higher fungicidal activity (the MIC value was 0.35-0.7μg/ml for the AmB-Cu (II) complex, and 0.45-0.9μg/ml for Fungizone) due to increased induction of oxidative damage with rapid inhibition of the ability to reduce tetrazolium dye (MTT). In the NHDF cell line, the CC 50 value was 30.13±1.53μg/ml for the AmB-Cu(II) complex and 17.46±1.24μg/ml for (Fungizone), therefore, the therapeutic index (CC 50 /MIC 90 ) determined in vitro was 86.09-43.04 for the AmB-Cu(II) complex and 38.80-19.40 for Fungizone. The lower cytotoxicity of the AmB-Cu(II) complex in human cells resulted from lower accumulation of cellular and mitochondrial reactive oxygen species. This phenomenon was probably caused by the induction of successful antioxidant defense of the cells. The mechanism of the reduced cytotoxicity of the AmB-Cu(II) complex needs further investigation, but the preliminary results are very promising., (Copyright © 2016 Elsevier B.V. All rights reserved.)

Aim: Our goal was to improve treatment outcomes for visceral leishmaniasis by designing nanocarriers that improve drug biodistribution and half-life. Thus, long-acting mannose-anchored thiolated chitosan amphotericin B nanocarrier complexes (MTC AmB) were developed and characterized., Materials & Methods: A mannose-anchored thiolated chitosan nanocarrier was manufactured and characterized. MTC AmB was examined for cytotoxicity, biocompatibility, uptake and antimicrobial activities., Results: MTC AmB was rod shaped with a size of 362 nm. MTC AmB elicited 90% macrophage viability and 71-fold enhancement in drug uptake compared with native drug. The antileishmanial IC 50 for MTC AmB was 0.02 μg/ml compared with 0.26 μg/ml for native drug., Conclusion: These studies show that MTC can serve as a platform for clearance of Leishmania in macrophages., Competing Interests: Financial & competing interests disclosureThis work was supported by the UNESCO-L'Oréal International Fellowship for Young Women in Life Sciences and NIH grants P01 DA028555, R01 NS36126, P01 NS31492, 2R01 NS034239, P01 MH64570, P01 NS43985, P30 MH062261 and R01 AG043540. The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.No writing assistance was utilized in the production of this manuscript.

Background: Amphotericin B, designated as the gold standard among antifungal drugs is the only fungicidal effective against systemic fungal infections. But this drug has various pitfalls associated with it, to bypass which various techniques have been employed and resulted in a variety of lipid based commercially available formulations, which demolished only few of the shortcomings associated with this drug. Further, improvement in the delivery systems of Amphotericin B is advancing at increasingly frenetic pace, to surmount its research and to exploit its therapeutic potency with least toxicities., Method: The patent search on "Amphotericin B for its safe and effective delivery" has been carried out to present assimilated information on the patents of the universally accepted Amphotericin B formulations and technologies. Also, the area of focus was the physicochemical properties of Amphotericin B, their role in formulation development and also nanotechnology based formulations of Amphotericin B., Results: Amphotericin B possesses poor aqueous solubility and systemic toxicity rendering obstacle in its formulation development. The interest of scientists and pharmaceutical industries to make further investments in the development of Amphotericin B formulations is due to rare occurrence of resistance to this drug. To bypass these drawbacks, various techniques have been patented which resulted in a variety of commercially available formulations to overcome the limitations of high cost, limited availability, poor storage stability and poor patient compliance. In lieu to this, scientists have developed and patented many novel drug delivery system based formulations and technologies such as use of novel carriers, modification in process for production and purification of Amphotericin B, formation of salts and complexes etc. to bring in limelight the benefits of this wonder drug., Conclusion: The purpose of the article is to present assimilated information regarding patents on Amphotericin B formulations and technologies., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.)

Amphotericin B (AmB) is the drug of choice in the treatment of invasive fungal infections and visceral leishmaniasis. Although AmB has a higher selectivity for ergosterol (present in fungi and Leishmania spp. membrane) than for cholesterol, mammalian cells are affected by AmB, mainly in its oligomeric aggregated form, resulting in side effects, especially nephrotoxicity. The development of nanotechnology-based drug delivery systems for AmB is a promising avenue since nanoparticles have the ability to target drugs to the infected cells, and their prolonged drug release profile permits longer contact between the drug and the fungi/parasite. In this review, we made an overview about nanoparticles as colloidal carriers for AmB, including polymeric-based nanoparticles, protein-based nanoparticles and solid lipid-based nanoparticles with respect to their application for the treatment of invasive fungal infections and leishmaniasis., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.)

A strategy has been devised for increasing the cellular selectivity of membrane-disrupting antibiotics based on the attachment of a facially amphiphilic sterol. Using Amphotericin B (AmB) as a prototype, covalent attachment of cholic acid bound to a series of α,ω-diamines has led to a dramatic reduction in hemolytic activity, a significant reduction in toxicity toward HEK293T cells, and significant retention of antifungal activity.

A comparative study on the effect of an antibiotic amphotericin B (AmB) and its copper complex on the multicomponent monolayers imitating the outer leaflet of human erythrocyte membrane has been performed by means of the Langmuir monolayer technique. The properties of mixed films were analyzed by thermodynamic description of the interactions between the molecules complemented with the morphology of monolayers established by Brewster angle microscopy (BAM). The results revealed differences in the molecular organization of the two antibiotic forms at the air/water interface, which were explained by the different spatial structure of the complex. The lipophilicity of the complex contributed to considerably more effective interactions with the components of the model membrane, compared to pure antibiotic, expressed by negative values of the excess of free energy of mixing ΔG exc in the whole range of mole fractions. The mixed films with AmB were more stable as the proportion of lipids in the mixture increased. BAM images demonstrated that the addition of antibiotic at high content into the lipid mixture led to the formation of crystallite structures within the film, probably caused by the expelling of AmB molecules from mixed monolayers. These findings could help to explain the mechanism of the hemolytic activity of polyene antibiotics.

The electro-osmotic flow, a significant factor in capillary electrophoretic separations, is very sensitive to small changes in structure and surface roughness of the inner surface of fused silica capillary. Besides a number of negative effects, the electro-osmotic flow can also have a positive effect on the separation. An example could be fused silica capillaries with homogenous surface roughness along their entire separation length as produced by etching with supercritical water. Different strains of methicillin-resistant and methicillin-susceptible Staphylococcus aureus were separated on that type of capillaries. In the present study, fused-silica capillaries with a gradient of surface roughness were prepared and their basic behavior was studied in capillary zone electrophoresis with UV-visible detection. First the influence of the electro-osmotic flow on the peak shape of a marker of electro-osmotic flow, thiourea, has been discussed. An antifungal agent, hydrophobic amphotericin B, and a protein marker, albumin, have been used as model analytes. A significant narrowing of the detected zones of the examined analytes was achieved in supercritical-water-treated capillaries as compared to the electrophoretic separation in smooth capillaries. Minimum detectable amounts of 5 ng/mL amphotericin B and 5 μg/mL albumin were reached with this method., (© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)