Amphotericin B is a broad-spectrum polyene antimycotic with activity against pathogenic yeasts, moulds, dimorphic fungi, and in vitro also against dermatophytes. The first gereal characterization appeared in 1961. After some partial structures were determined, the complete structure was published in 1970, and the total synthesis in 1987.

Stability

Amphotericin B is unstable to heat and prolonged exposure to light. It should be stored in the dark and kept refrigerated. In solution it decomposes at pH < 4 and > 10. Solutions show an optimum stability in a citrate – phosphate buffer at pH5–7.

Indications

Amphotericin B is effective in therapy of Candida infections, also including generalized and disseminated forms, caused by Candida albicans and other pathogenicCandida species. Further, amphotericin B is indicated in the therapy of mycotic diseases such as histoplasmosis, sporotrichosis, cryptococcosis, blastomycosis, aspergillosis, zygomycosis, and coccidioidomycosis. Although the substance shows an in vitro activity against dermatophytes, amphotericin B is not indicated in the therapy of dermatophytoses, mostly due to toxicity and stability problems and high cost. In the treatment of generalized mycoses, often a synergistic effect between amphotericin B and fluorocytosine, and an antagonistic effect between amphotericin B and azole antimycotics is observed (the latter with the exception of CNS cryptococcosis due to Cryptococcus neoformans).

Topical application of amphotericin B is highly effective and well tolerated in the treatment of cutaneous and mucocutaneous candidoses. This is also true for inhalation and instillation. Local irritations and allergic reactions may occur in rare cases and are partly due to the galenic formulation.