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Absorption of Ambien occurs rapidly in the stomach.
Because the pH of the stomach is much lower than the pKa of Ambien (about
6), Ambien becomes protonated, giving it a positive charge and making it
soluble. Due to the stomach pH being significantly lower, Ambien
dissolves completely. After dissolution, Ambien continues down the
GI tract into the small intestine. In the lower intestine, the pH
becomes very similar to the pKa. This causes deprotonation (seen
below). It is here that Ambien is most neutral, allowing it to easily
and rapidly cross the lipid bilayer of the cells of the intestine lining
and be absorbed into the bloodstream.
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