amphotericin \amphotericin\, amphotericin B \amphotericin B\n. 1. an antibiotic and antifungal agent ({C47H73NO17}), produced by a strain of {Streptomyces nodosus}. It is one of a class of polyene macrolide antibiotics effective against fungal infections. It has a molecular weight of 924.11; it is soluble in oganic solvents but only slightly soluble in water. Syn: Fungizone. [WordNet 1.5]