24  Chikhale et al. [638] looked at the permeability of a series of peptides and found that the permeabilities did not correlate with the n-octanol/water partition coefficient but did correlate with the number of hydrogen bonds they could form. If the hydrogen bonds were formed only in the water and not in either n-octanol or the membrane core, then n-octanol would be expected to be a reasonable model for the core and the discrepancy they observed should not have been seen. See also [169].