Permeability of Cyclic Peptide Macrocycles and Cyclotides and Their Potential as Therapeutics.

Macrocycles have emerged as a viable approach for the modulation of tough targets in drug discovery. In this Innovations article we discuss recent progress toward the design of cell permeable and orally bioavailable peptide macrocycles and cyclotides and provide a perspective for their potential as therapeutics. We highlight design concepts that may be broadly relevant to drug discovery efforts beyond the rule of five.