Transport of antimicrobial agents using peptide carrier systems: anticandidal activity of m-fluorophenylalanine--peptide conjugates.

A series of di- and tripeptides containing D- and L-m-fluorophenylalanine was prepared and tested in vitro for the ability to inhibit the growth of the yeast Candida albicans. The results demonstrate that peptides containing L-m-fluorophenylalanine inhibited the growth of C. albicans with minimum inhibitory concentrations (MIC's) ranging from 0.5 to 63 micrograms/mL. The parent L-m-fluorophenylalanine and peptides containing D-m-fluorophenylalanine were inactive (MIC greater than 250 micrograms/mL) in these tests. The results of competitive antagonism studies support peptide transport mediated entry of the inhibitory peptides, followed by release of L-m-fluorophenylalanine inside the cell.