Development of polyion complex micelles for encapsulating and delivering amphotericin B

A block copolymer poly(2-ethyl-2-oxazoline)-block-poly(aspartic acid) (PEOz-b-PAsp) was synthesized and investigated as the carrier of antifungal drug amphotericin B (AmB). Polyion complex (PIC) micelles with clear core–shell structures were identified by TEM, which revealed that the PAsp segment became hydrophobic after it interacted with AmB. PEOz-b-PAsp increased not only the solubility of AmB but also simultaneously the drug potency. The prolonged release of AmB from micelles effectively inhibited the growth of Candida albicans even after three days of administration. Moreover, the in vitro cytotoxicity of AmB-loaded micelles was less than that of Fungizone®, which is a powerful antifungal antibiotic that is adopted to treat various fungal infections. The PEOz-b-PAsp PIC micelles with lower cytotoxicity and higher potency than Fungizone® represent a potential means of encapsulating basic/amphoteric drugs.