Abstract

The human stomach is capable of absorbing most acidic drugs and the very weakly basic drugs. Salicylic acid, aspirin, thiopental, secobarbital and antipyrine, which are undissociated in the acidic gastric contents, were readily absorbed. Phenol red, quinine, ephedrine and aminopyrine, which are almost completely ionized in acid solution were not absorbed. These results are compatible with the hypothesis that drugs are absorbed by passive diffusion of their lipid soluble undissociated form. Many drugs may be absorbed by the human stomach as rapidly or more rapidly than ethyl alcohol.