Disposition and pharmacokinetics of L-N6-(1-iminoethyl)lysine-5-tetrazole-amide, a selective iNOS inhibitor, in rats

✍ Scribed by Ji Y. Zhang; Yuefen Wang; Mark N. Milton; Lori Kraus; Alan P. Breau; Susan K. Paulson

• Publisher: John Wiley and Sons
• Year: 2004
• Tongue: English
• Weight: 210 KB
• Volume: 93
• Category: Article
• ISSN: 0022-3549
• DOI: 10.1002/jps.20048

✦ Synopsis

The metabolism, pharmacokinetics, tissue distribution, and excretion of L-N6-(1-iminoethyl)lysine-5-tetrazole-amide (L-NIL-TA), a selective inducible NO synthase (iNOS) inhibitor, were investigated in rats. [ 14 C]L-NIL-TA is extensively metabolized after either oral or IV administration with a minor amount (<1%) excreted as the prodrug. L-NIL-TA is metabolized via a single hydrolysis pathway to form the active drug, L-N6-(1-iminoethyl)lysine (L-NIL). The oxidative deamination of 2-amino group of L-NIL forms a 2-keto metabolite (M5), which further loses carbon dioxide to yield a carboxylic acid metabolite (M6). Acetylation of L-NIL and M5 resulted in the formations of metabolites M7 and M4, respectively. Complete recovery of the radioactive dose was achieved after either oral (91.2% in urine and 4.66% in feces) and IV (99.3% in urine and 5.11% in feces) administration. L-NIL-TA-related material was extensively distributed to the tissues, with the highest concentration of radioactivity being found in muscle. Maximal concentration of radioactivity was reached between 0.5 and 1 h post-dose in the majority of tissues, with the exception of muscle and skin where the maximal concentrations were achieved at 8 h post-dose.