Effects of divalent amino acids on iron absorption

Solutions of each of 10 amino acids or ascorbic acid were mixed with iron and orally administered to rats. Iron was absorbed to a statistically significantly greater extent (p less than 0.05) when mixed with asparagine, glycine, serine, or ascorbic acid as compared with a control solution of iron. The largest effects were for asparagine and glycine, which also increased iron absorption to a significantly greater extent (p less than 0.001) than did serine or ascorbic acid. No statistically significant increase in iron absorption occurred when any of the other amino acids was mixed with iron. The extent of iron absorption from each test solution, as measured by area under the concentration of iron-59 in the blood-time curve (r2 = 0.0002), and the initial rate of iron absorption for each test solution (r2 = 0.01) showed no correlation with the stability constant of the amino acid-iron complex.     

Absorption of 3H-benzocaine from ointments following rectal administration in rats.

Total radioactivity in the blood of rats for 5 hr following rectal administration of 3H-benzocaine in oleaginous, absorption, emulsion (water-in-oil and oil-in water), and water-soluble ointment vehicles was measured. The release was greatest from the water-soluble vehicle and followed the same relative order as seen in an earlier in vitro experiment. No intact benzocaine was found in the blood using radiochromatography. In vitro hydrolysis of benzocaine by rat blood did not occur as determined with the techniques of this experiment.