口A. Simple diffusion Most drugs are weak acids or bases Weak acid Their diffusion Weak base passing through cell Lipid membrane depen ds Lipid membrane membrane the lipid-soluble state BH (un-ionized form) HA B A HA Body Bod Body Bod compartment compartmen compartment compartmentA . Simple diffusion Most drugs are weak acids or bases. Their diffusion passing through cell membrane depends the lipid -soluble state (un -ionized form)