Synthesis and characterisation of a new amphotericin b–methoxypoly(ethylene glycol) conjugate

Sedlák, Miloš; Buchta, Vladimı́r; Kubicová, Lenka; Šimůnek, Petr; Holčapek, Michal; Kas̆parová, Pavla

doi:10.1016/s0960-894x(01)00532-7

Cited by 27 publications

(15 citation statements)

References 19 publications

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“…AMB-PEG conjugates have been synthesized by linking AMB to methoxy-PEG via carbamate linkages to its amine group, such that approximately half of the AMB is linked to PEG, with the rest being attached non-covalently. These compounds possess in vitro antifungal activity comparable to that of AMB deoxycholate, although their relative toxicity to mammalian cells was not investigated [ 17 ]. PEG has also been conjugated to AMB via its carboxylic acid group [ 18 ], generating less toxic compounds with demonstrated in vivo antifungal efficacy [ 19 , 20 ].…”

Section: Introductionmentioning

confidence: 99%

Characterization of a Polyethylene Glycol-Amphotericin B Conjugate Loaded with Free AMB for Improved Antifungal Efficacy

et al. 2016

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Amphotericin B (AMB) is a highly hydrophobic antifungal, whose use is limited by its toxicity and poor solubility. To improve its solubility, AMB was reacted with a functionalized polyethylene glycol (PEG), yielding soluble complex AmB-PEG formulations that theoretically comprise of chemically conjugated AMB-PEG and free AMB that is physically associated with the conjugate. Reverse-phase chromatography and size exclusion chromatography methods using HPLC were developed to separate conjugated AMB-PEG and free AmB, enabling the further characterization of these formulations. Using HPLC and dynamic light scattering analyses, it was observed that the AMB-PEG 2 formulation, having a higher molar ratio of 2 AMB: 1 PEG, possesses more free AMB and has relatively larger particle diameters compared to the AMB-PEG 1 formulation, that consists of 1 AMB: 1 PEG. The identity of the conjugate was also verified using mass spectrometry. AMB-PEG 2 demonstrates improved antifungal efficacy relative to AMB-PEG 1, without a concurrent increase in in vitro toxicity to mammalian cells, implying that the additional loading of free AMB in the AMB-PEG formulation can potentially increase its therapeutic index. Compared to unconjugated AMB, AMB-PEG formulations are less toxic to mammalian cells in vitro, even though their MIC50 values are comparatively higher in a variety of fungal strains tested. Our in vitro results suggest that AMB-PEG 2 formulations are two times less toxic than unconjugated AMB with antifungal efficacy on Candida albicans and Cryptococcus neoformans.

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Section: Introductionmentioning

confidence: 99%

Characterization of a Polyethylene Glycol-Amphotericin B Conjugate Loaded with Free AMB for Improved Antifungal Efficacy

et al. 2016

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“…AmB can be conjugated to poly(ethylene glycol) (PEG) with various molecular weights to obtain a polymeric drug. The conjugates showed increased solubility in aqueous solution, and reduced toxicity 8–10…”

Section: Introductionmentioning

confidence: 99%

Galactomannan–amphotericin B conjugate: synthesis and biological activity

Farber

Ickowicz

Sionov

et al. 2010

Polymers for Advanced Techs

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Polysaccharide conjugated amphotericin B (AmB) was synthesized by conjugation of AmB to oxidized galactomannan (GM) by reductive amination and tested for antifungal activity. AmB conjugates were investigated for their ability to inhibit Candida albicans growth. Antifungal efficiency of the synthetic AmB-GM depends on both, AmB content and duration of exposure. The most potent compound was a conjugate which contains 40% AmB with minimal inhibition concentration of 0.25 mg/l. In vitro toxicity analysis revealed that conjugates with 20, 30, and 40% w/w AmB content have no hemolytic effect and no influence on the viability of the VERO kidney cells. Furthermore, maximal tolerant dose (MTD) of the conjugate was determined in vivo and found to be 60 mg/kg (equivalent to AmB), while commercial Fungizone 1 demonstrated increased toxicity of 3 mg/kg on mice model.

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“…For example, side effects, such as nephrotoxicity, would be caused by cytoclasis due to AmB binding to a cholesterol-containing membrane. 27,28) From the viewpoint of AmB having these characteristics as an antifungal drug, it might be speculated that the dramatically difference of affinity between ergosterol-and cholesterol-containing membrane would not be observed, indicating that AmB might show also the binding affinity to cholesterol-containing membrane.…”

Section: Resultsmentioning

confidence: 99%

High-Throughput and Sensitive Assay for Amphotericin B Interaction with Lipid Membrane on the Model Membrane Systems by Surface Plasmon Resonance

Onishi

Kamimori

2013

Biological & Pharmaceutical Bulletin

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In the present study, we developed a high-throughput and sensitive assay for interactions of amphotericin B (AmB) with two model lipid membranes, which mimicked mammal cell membrane and fungal membrane using surface plasmon resonance (SPR). The binding kinetics of AmB to the membrane could be analyzed by multiple sensorgrams obtained at different AmB concentrations, indicating that the binding properties could be clarified for an approximately 7-fold concentration range. AmB showed an approximately 18-fold higher affinity for ergosterol-containing membrane than for cholesterol-containing membrane. We also optimized the procedure for the reproducible immobilization of liposome containing the sterols and the estimation of binding kinetics of AmB to the lipid membranes, and the sensitivity of AmB to membrane interaction was 20-fold higher, compared with the reported method. The throughput of the established method for the binding kinetics characterization was calculated to be 10 compounds a day. The results demonstrate that the established SPR method could be a valuable tool for predicting selective binding to sterol-containing membranes.Key words amphotericin B; surface plasmon resonance; lipid membrane Amphotericin B (AmB), an antifungal polyene macrolide antibiotic produced by Streptomyces nodosus, is known as the gold-standard drug for the treatment of many systemic fungal infections or "deep mycoses" that could be life-threatening for specific populations, such as immunocompromised, transplant and cancer patients.1) The route of administration for antifungal therapies with AmB is intravenous (i.v.) infusion. This treatment requires hospitalization and has numerous side effects, such as nephrotoxic potential.2-4) Therefore, the development of new antifungal antibiotics is desired for more simplified treatment and reduction of side effects.AmB has a highly hydrophobic, water-insoluble molecule with amphiphilic properties, and the drug product formulation of AmB is quite challenging. 5) Although there are various ways to formulate new drug products based on the AmB skeleton, no formulation of AmB is currently available for systemic treatment of infection after oral administration. It is generally accepted that an ion-permeable channel formed across the bilayer membrane is responsible for the biological activity of AmB.6,7) The antibiotic activity of AmB is believed to be primarily due to a higher affinity for ergosterol, a primary fungal sterol, than for cholesterol in mammalian membranes.8-11) Thus, in order to develop a new drug based on the AmB skeleton with better antibiotic efficacy and fewer side effects, such as nephrotoxicity, diverse drug candidates need to be examined for their membrane affinity.The affinity of AmB for lipid membranes is one of the critical factors influencing selectivity and potency. Surface plasmon resonance (SPR)-based biosensors have been already applied to study the membrane-binding properties of drugs with the aim of gaining insight into their mechanism of action. 12,13) We and ou...

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Synthesis and characterisation of a new amphotericin b–methoxypoly(ethylene glycol) conjugate

Cited by 27 publications

References 19 publications

Characterization of a Polyethylene Glycol-Amphotericin B Conjugate Loaded with Free AMB for Improved Antifungal Efficacy

Characterization of a Polyethylene Glycol-Amphotericin B Conjugate Loaded with Free AMB for Improved Antifungal Efficacy

Galactomannan–amphotericin B conjugate: synthesis and biological activity

High-Throughput and Sensitive Assay for Amphotericin B Interaction with Lipid Membrane on the Model Membrane Systems by Surface Plasmon Resonance

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