Comparison of conventional and lipid emulsion formulations of amphotericin B: Pharmacokinetics and toxicokinetics in dogs

Incidence of acute kidney injury in dogs with systemic mycotic infections treated with amphotericin B (1996-2020)

BACKGROUND

Amphotericin-B (AmB) is an essential medication for the treatment of life-threatening systemic mycoses but the incidence and risk factors for acute kidney injury (AKI) after its administration are not known in dogs.

OBJECTIVE

Determine the incidence of and risk factors for AKI in dogs receiving AmB.

ANIMALS

Fifty-one client owned dogs receiving AmB for the treatment of systemic mycoses.

METHODS

Retrospective study. Signalment, potential risk factors, AKI development (creatinine ≥0.3 mg/dL from baseline), drug formulation (deoxycholate [AmB-D] or lipid complex [ABLC]), dose, and treatment duration were recorded. The probability of an AKI diagnosis was evaluated using a log-rank test. The incidence of AKI and odds ratios were calculated for potential risk factors.

RESULTS

Incidence of AKI was 5/12 (42%) for dogs receiving AmB-D and 14/39 (36%) for dogs receiving ABLC. Of the 19 dogs that developed AKI, 16 (84%) continued treatment after a pause in the planned dosing protocol. Fifty percent of dogs received a cumulative dose of 6.9 mg/kg for AmB-D and 22.5 mg/kg for ABLC (P < .01) at time of AKI diagnosis. ICU hospitalization (odds ratio [OR] 0.21, 95% confidence interval [CI]: 0.58-0.87) and inpatient status (OR 0.25, 95% CI: 0.07-0.86) were associated with decreased odds of AKI.

CONCLUSIONS AND CLINICAL IMPORTANCE

Incidence of AKI with AmB is common but does not always preclude continued treatment. The incidence of AKI is similar between AmB-D and ABLC, but dogs receiving ABLC tolerated a higher cumulative total dose before AKI diagnosis.

Enhancing the Antibiofilm Activity of β-1,3-Glucanase-Functionalized Nanoparticles Loaded With Amphotericin B Against Candida albicans Biofilm

Candida biofilm-related infections cause increased morbidity and mortality in patients with a reduced immune response. Traditional antifungal therapies have proven to be insufficient as the biofilm matrix acts as a perfusion barrier. Thus, novel methods are required to improve drug delivery and kill Candida within the biofilm. In this study, chitosan nanoparticles (CSNPs) loaded with Amphotericin B (AMB), which were functionalized with β-1,3-glucanase (Gls), were fabricated (CSNPs-AMB-Gls), and their antibiofilm activity against Candida albicans biofilm was evaluated in vitro. Scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM) were employed to examine biofilm architecture and cell viability. CSNPs-AMB-Gls inhibited planktonic cell growth and biofilm formation effectively and exhibited the highest efficacy on the removal of a mature biofilm than free AMB or CSNPs-AMB. The created nanoparticles (NPs) were found to penetrate the biofilm so as to directly interfere with the cells inside and disassemble the biofilm matrix. CSNPs-AMB-Gls could also eradicate biofilms from clinical isolates. These results suggest the potential applicability of CSNPs-AMB-Gls for the treatment of Candida biofilm-related infections.

Gender differences in acute toxicity, toxicokinetic and tissue distribution of amphotericin B liposomes in rats

Amphotericin B (AmB), an effective polyene drug with broad spectrum antifungal activity, is used for serious fungal infections. Liposomal amphotericin B (LAmB) is a lipid dosage form, which has a significantly improved toxicity profile compared with conventional amphotericin B deoxycholate (DAmB). This study focused on verifying the gender differences in the acute toxicity of LAmB and further exploring its causes. Acute toxicity study of LAmB and DAmB were performed in rats, and toxicity responses and mortality of different sexes were observed and recorded. Concentrations of AmB in rat plasma and tissues were determined by a fully validated UPLC-MS/MS assay. The results demonstrated that LAmB showed significant gender differences in acute toxicity, with more severe toxic symptoms and higher mortality for female rats at different doses, but the same differences were not observed for DAmB under the same condition. To explore the cause of differences, toxicokinetic and tissue distribution studies were performed and the results showed that female animals had higher drug exposure, longer half-life and lower plasma clearance compared to male rats, and the drug was mostly distributed in the liver and kidneys, in which female rats displayed a significant higher concentration than that of male rats.

A Quantitative LC-MS/MS Method for Determination of Liposomal Amphotericin B in Rat Plasma and Tissues and its Application to a Toxicokinetic and Tissue Distribution Study

Background::

Among the existing antifungal drugs, Amphotericin B is the first drug in the treatment of systemic fungal infections. However, its large adverse reactions limit the clinical application and Liposome Amphotericin B resolves the problem.

Objective::

In the present study, a rapid, simple, sensitive and efficient method based on LCMS/ MS for determination of liposomal Amphotericin B in rat plasma and tissue samples using natamycin as the internal standard has been developed and validated.

Methods:

The analytical samples contain the plasma and various tissues disposed of by protein precipitation and determination of liposomal Amphotericin B by an LC-MS/MS. Chromatographic separation was achieved on a Poroshell 120 EC-C18 column (4.6 mm × 50 mm, 2.7 μm) with 10 mmol/L ammonium acetate in water-acetonitrile by gradient elution at a flow rate of 0.7 mL/min. The MS analysis was conducted in positive electrospray ionization with Multiple Reaction Monitoring (MRM).

Results::

The calibration curves of plasma and tissues showed good linear range from 50 to 10000 ng/mL. The analytical samples containing plasma and tissues were stable under different storage conditions and temperature.

Conclusions: :

The developed LC-MS/MS method has been successfully applied to the studies of toxicokinetics and tissue distribution after intravenous injection of liposomal Amphotericin B to rats.

Lipid Systems for the Delivery of Amphotericin B in Antifungal Therapy

Amphotericin B (AmB), a broad-spectrum polyene antibiotic in the clinic for more than fifty years, remains the gold standard in the treatment of life-threatening invasive fungal infections and visceral leishmaniasis. Due to its poor water solubility and membrane permeability, AmB is conventionally formulated with deoxycholate as a micellar suspension for intravenous administration, but severe infusion-related side effects and nephrotoxicity hamper its therapeutic potential. Lipid-based formulations, such as liposomal AmB, have been developed which significantly reduce the toxic side effects of the drug. However, their high cost and the need for parenteral administration limit their widespread use. Therefore, delivery systems that can retain or even enhance antimicrobial efficacy while simultaneously reducing AmB adverse events are an active area of research. Among those, lipid systems have been extensively investigated due to the high affinity of AmB for binding lipids. The development of a safe and cost-effective oral formulation able to improve drug accessibility would be a major breakthrough, and several lipid systems for the oral delivery of AmB are currently under development. This review summarizes recent advances in lipid-based systems for targeted delivery of AmB focusing on non-parenteral nanoparticulate formulations mainly investigated over the last five years and highlighting those that are currently in clinical trials.

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.

Toxicokinetics, Tissue Distribution, and Excretion of Dufulin Racemate and Its R ( S)-Enantiomers in Rats

Dufulin is a plant antiviral agent with a novel molecular structure and has been used widely to prevent and control tobacco and rice viral diseases. In this study, an UHPLC-MS/MS method was developed for rapid determination of dufulin racemate ( rac-DFL) and its R ( S)-enantiomers in rat plasma, tissues, urine, and feces. A MALDI-MSI method was further used for visual research on tissue distribution after intragastric administration of the three analytes. Toxicokinetic study showed that both ( R)-enantiomer of dufulin (( R)-DFL) and ( S)-enantiomer of dufulin (( S)-DFL) had a faster ability to reach C_max than that of rac-DFL. ( R)-DFL and ( S)-DFL had a similar T_1/2, though both were significantly lower than rac-DFL. C_max of rac-DFL was obviously higher than ( R)-DFL or ( S)-DFL. Meanwhile, C_max of ( S)-DFL was only about 60% of ( R)-DFL. Rac-DFL and its R ( S)-enantiomers had a dose-dependent toxicokinetic profile. Tissue distribution results revealed rac-DFL, ( R)-DFL, and ( S)-DFL mainly distributed in the liver and kidney, but the maximum concentration was only ng/g grade and could significantly degrade within 3 h. This indicates that dufulin does not cause liver and kidney toxicity in animals. In addition, rac-DFL and its R ( S)-enantiomers have not been detected in brain tissue. Cumulative excretion of rac-DFL and its R ( S)-enantiomers within 24 h in urine and feces were less than 22.85% indicating that they mainly excreted as metabolites. These results could provide evidence for the in-depth toxicity evaluation of dufulin pesticide. In addition, its metabolic selectivity information in vivo has also been obtained.