Abstract
Absorption of isomeric N1-heterocyclic sulfonamides was studied from the rat small intestines employing isomeric N-methyl sulfonamides in addition to usual antibacterial sulfonamides. The physicochemical properties of the compounds were studied in reference to their isomeric form in solution. Following Shepherd's method sulfapyridine and sulfathiazole were confirmed to exist as imido form about 84% and 100% respectively in aqueous solution. N1-methyl derivatives and ring N-methyl derivatives were adopted as a model of amido form and imido form respectively and the differences of their physicochemical properties and absorption characteristics from undissociated molecules of their parent compounds were discussed. Also relations of physicochemical properties and absorption were persuaded following Hansch's method. And absorption rate constant of undissociated form of the compounds under study was likely to be related to partitioning to n-octanol and molecular weight.
