TABLE 2

Anion concentration of in vitro test matrices designed to mimic GI tract compartments

MatrixAcetate (mM)Chloride (mM)Phosphate (mM)Citrate (mM)Taurocholate (mM)Oleic Acid (mM)
SGFa098.00000
SIBb036.020.0000
SOBc50.036.07.01.55.030.0
  • a SGF, pH = 1.2; it mimics the acidic environment of the fasted stomach and reflects an optimal condition for binding of HCl.

  • b SIB, pH = 5.5; pH is representative of the human proximal small intestine (duodenum and early jejunum), and that contains chloride and a high concentration of phosphate as a potential competing anion to chloride. The solution was buffered by 2-(N-morpholino)ethanesulfonic acid.

  • c SOB, pH = 6.2; pH and competing anion content (bile acid, citrate, oleic acid, and acetate) represent components of the human distal small intestine (late jejunum, ileum) and cecum. The solution was buffered by N,N-bis(2-hydroxyethyl)-2-aminoethanesulfonic acid.