Aqueous channels hydrophilic compounds

The lipid layer favors uptake of nonpolar compounds (lipophilic having an affinity for fat), while certain globular proteins embedded in the membrane form aqueous pores or channels, which allow penetration of small polar substances (hydrophilic having an affinity for water) such as ethanol or ions such as those of sodium chloride. 

Molecules added to biological systems may find their way into membranes and associate in the lipid system. Several compounds of fungal or bacterial origin (such as alamethacin, which forms micelles in aqueous systems [350]) readily incorporate into planar lipid bilayers and form channels by self-association, channels which allow the translocation of ions and other hydrophilic species through the otherwise hydrophobic membranes. Based on calculations made of the rates of association possible for channel formation by lateral diffusion of... 

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