pH partition theory

pH partition theory is a theory developed in the early 20th century as an attempt to explain drug bioavailability. It is the tendency for acids to accumulate in basic fluid compartments, and bases to accumulate in acidic compartments. The reason for this phenomenon is that acids become negatively electric charged in basic fluids, as they donate a proton. On the other hand, bases become positively electric charged in acid fluids, as they receive a proton. Since electric charge decreases the membrane permeability of substances, once an acid enters a basic fluid and becomes electrically charged, it cannot escape that compartment with ease and therefore accumulates, and vice versa with bases.

See also

• Ion trapping
• Acid dissociation constant - pK_a
• Henderson-Hasselbalch equation