Anidulafungin

Chemical Identity

Property	Value
Chemical Formula	C58H73N7O17
Molecular Weight	1140.24 Da
CAS Number	166663-25-8
Peptide Class	Lipopeptide (Echinocandin)
Origin	Semi-synthetic (from Aspergillus nidulans var. echinulatus)

Structure

Anidulafungin is a semi-synthetic echinocandin derived from echinocandin B. It features a cyclic hexapeptide core with three hydroxyornithine residues and a C5 lipophilic tail. Uniquely among echinocandins, it undergoes slow chemical degradation rather than hepatic metabolism, eliminating drug-drug interaction concerns.

Mechanism of Action

Anidulafungin inhibits beta-1,3-D-glucan synthase, blocking fungal cell wall synthesis. It is fungicidal against Candida species and fungistatic against Aspergillus. The enzyme target is specific to fungi, with no mammalian homolog.

Clinical Applications

• Invasive candidiasis/candidemia: First-line therapy
• Esophageal candidiasis: Including fluconazole-refractory cases
• Candida peritonitis: Intra-abdominal candidiasis
• Aspergillosis: Combination or salvage therapy

Pharmacokinetics

• Half-life: 26 hours
• Protein binding: >99%
• Metabolism: Spontaneous chemical degradation (non-enzymatic)
• Elimination: Fecal (primarily as degradation products)
• Loading dose: 200 mg day 1, then 100 mg daily

Safety and Side Effects

Hepatotoxicity (mild LFT elevations), hypokalemia, diarrhea, nausea, and histamine-related flushing with rapid infusion. No significant drug-drug interactions due to non-enzymatic elimination.

References

• Krause, D.S., et al. (2004). Anidulafungin versus fluconazole for esophageal candidiasis. Clinical Infectious Diseases, 39, 766-772.
• Vazquez, J.A., et al. (2014). Anidulafungin for invasive candidiasis. Clinical Infectious Diseases, 58, 1207-1216.