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Amphotericin B lipid complex in the treatment of experimental cryptococcal meningitis and disseminated candidosis
1Department of Medicine, Duke University Medical Center, Durham, NC 27710.
Abstract:
In the quest for safer and more effective antifungal agents, amphotericin B (AMB) has been placed in a variety of lipid preparations. In this study, we examined the efficacy of amphotericin B lipid complex (ABLC) on experimental cryptococcal meningitis and disseminated candidosis. This formulation is relatively safe compared to the parent compound, and therefore doses ten times greater than the commercial amphotericin B deoxycholate can be given to rabbits. Although at equal doses the ABLC preparation is less potent than AMB, a higher dose of ABLC was rapidly fungicidal in the contexts of both a central nervous system infection with Cryptococcus neoformans during immune suppression, and a heart and kidney infection with Candida albicans. Rapid sterilization of tissue should be a goal of antifungal drug therapy, particularly in the immune compromised host. From these studies, this AMB lipid formulation has the ability to produce rapid fungicidal activity in vivo, but it requires higher doses than AMB deoxycholate. Clinical trials in humans must examine carefully the therapeutic-toxic ratio in dose-escalation protocols to determine the optimal dosage strategy for this agent.
Insights
Amphotericin B lipid complex (ABLC) shows rapid fungicidal activity against fungal infections like cryptococcal meningitis and candidosis in rabbits. Higher doses are needed compared to amphotericin B deoxycholate.
Area of Science:
- Mycology
- Pharmacology
- Infectious Diseases
Background:
- Amphotericin B (AMB) is a potent antifungal, but its toxicity necessitates safer formulations.
- Lipid formulations of AMB aim to improve safety and efficacy.
- Amphotericin B lipid complex (ABLC) is one such formulation.
Purpose of the Study:
- To evaluate the efficacy of ABLC against experimental cryptococcal meningitis and disseminated candidosis.
- To compare the fungicidal activity of ABLC with conventional amphotericin B deoxycholate.
- To assess the safety and therapeutic-toxic ratio of ABLC in an animal model.
Main Methods:
- Experimental infection models in rabbits were established for *Cryptococcus neoformans* (meningitis) and *Candida albicans* (disseminated candidosis).
- Animals were treated with ABLC at doses significantly higher than conventional AMB.
- Fungicidal activity and tissue sterilization were assessed in central nervous system, heart, and kidney tissues.
Main Results:
- ABLC demonstrated rapid fungicidal activity in vivo against both *C. neoformans* and *C. albicans* infections.
- Higher doses of ABLC were required to achieve comparable fungicidal potency to AMB deoxycholate.
- The ABLC formulation allowed for administration of doses ten times greater than AMB deoxycholate in rabbits due to improved safety.
Conclusions:
- Amphotericin B lipid complex exhibits rapid *in vivo* fungicidal activity, particularly valuable for immunocompromised hosts.
- Optimal dosage strategies require careful evaluation of the therapeutic-toxic ratio in human clinical trials.
- Further investigation into dose-escalation protocols is crucial for determining the clinical utility of ABLC.