ABSTRACT
Micafungin sodium (Mycamine, FK463) is a water-soluble semisynthetic compound belonging to the echinocandin class of antifungals. It is synthesized through chemical modification of the cyclic hexapeptide FR901370, a natural fermentation product from Coleophoma empetri. The chemical structure is pneumocandin A0,1-[(4R, 5R] Similar to other e-4,5-dihydroxy-N2 -[4-[5-[4-(pentyloxy)phenyl]-3-isoxazoly]benzoyl]-L-orthnithine]-4-[4S)-4-hydroxy-4-[4-hydroxy-3-(sulfooxy)phenyl]-L-threonine]-, monosodium salt (Figure 147.1). Similar to other echinocandin compounds approved for clinical use (caspofungin and anidulafungin), the addition of a modified N-linked acyl lipid side-chain to the cyclic hexapeptide nucleus improves antifungal potency, likely through anchoring the compound to the phospholipid bilayer of the fungal cell membrane. While the mechanism remains to be fully elucidated, micafungin and the other echinocandins exert their antifungal activity through the noncompetitive inhibition of 1,3-β-D glucan synthase, an enzyme responsible for the biosynthesis of 1,3,-β-D-glucan which is a crucial structural component of the cell wall for many fungal pathogens. Depletion of this integral glucan polymer leads to osmotic instability, cell lysis, and cell death. Micafungin is primarily effective against Candida and Aspergillus species, with marginal activity against other molds and basidiomycetes likely due to differences in the structural components of the fungal cell wall or compensatory mechanisms in these species. Chemical structure of micafungin. https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9781315152110/08d8042d-9481-4a8d-8c27-9bd589f6de6b/content/fig147_1.tif" xmlns:xlink="https://www.w3.org/1999/xlink"/>
