Liposome-Trapped Nystatin in Growth Inhibition ofAspergillus niger

Liposome-trapped nystatin caused growth inhibition of the wild type A. niger and its nystatin-resistant mutant at concentrations at which the free drug or free drug plus empty liposomes was significantly less effective. In the case of the mutant, negatively charged liposomes made from phosphatidylcholine (PC)/ phosphatidyiethanolamine (PE)ldicetyl phosphate (DCP) (1:1:0.22) showed the highest efficiency (75%). However, neutral liposomes made from PC/PE (1:1) caused 68% growth inhibition of the wild type and were most effective in this system. Growth inhibition studies as a function of time and increasing concentrations of nystatin entrapped in the above liposome systems showed significantly greater inhibition of both the wild type and the mutant. This indicates that superior efficacy is due to entrapment of nystatin in liposomes. the increased efficiency of negatively charged liposomes in the case of the mutant may be due to electrostatic attraction that favors the interaction between the liposomal membrane and the fungal cell surface in this case.