Synthesis and Properties of N,N'-Bis(5-Aminosalicyl)-L-Cystine as a Colon-Specific Deliverer of 5-Aminosalicylic Acid and Cystine.

N,N'-bis(5-aminosalicyl)-L-cystine (5-ASA-Cys) was prepared by a simple synthetic route. 5-ASA-Cys was not degraded in pH 1.2 and 6.8 buffer solutions, and in the homogenates of the upper intestine. In marked contrast, 5-ASA-Cys was deconjugated extensively to liberate 5-ASA in the cecal contents. Upon oral administration of 5-ASA-Cys to rats, the plasma concentration of 5-ASA-Cys was extremely low and the urinary recovery of 5-ASA-Cys was ∼ 10% of the dose. These results suggest that 5-ASA-Cys administered orally is delivered efficiently to the large intestine followed by deconjugation to liberate 5-ASA and cystine. [ABSTRACT FROM AUTHOR]