Abstract
As a physico-chemical approach to an understanding of biopharmaceutical phenomena, discussions were given on the basis of the adsorption of sulfonamides by carbon black from aqueous solution. The hydrophobic interaction was considered to be weakened upon addition of urea, resulting in a decrease in adsorption of sulfonamides from aqueous solution. The introduction of Me- or MeO- into the molecular structure of sulfonamide caused the increases in the adsorption by carbon black, in the binding to bovine serum albumin, and in the absorption from rat small intestine. Plotting the adsorption data of sulfonamides against the partition coefficient in butanol-water system reported, a good correlation was given. Then, plotting the same data against the absorption rate from rat small intestine reported, a correlation was observed. It was, therefore, expected that the hydrophobic interaction between the drugs and the intestinal membrane forms an important factor in absorption phenomena.
