Kinetic profiles of tianeptine and its MC5 metabolite in plasma, blood and brain after single and chronic intraperitoneal administration in the rat.

This study was conducted to determine kinetic profiles of the antidepressant tianeptine and its main metabolite (named MC5) in plasma, blood and brain after single (10 mg.kg-1) and chronic (10 mg.kg-1.day-1 and 2 x 10 mg.kg-1.day-1 for 15 days) intraperitoneal administration in Wistar rats. In plasma, tianeptine and MC5 reached a peak very quickly (5 and 15 min post administration respectively). Following the peak, disappearance of tianeptine was faster than that of MC5 with terminal half-lives close to 2.5 and 6.5 h respectively. During chronic treatment, accumulation of tianeptine was negligible, that of MC5 was slight as indicated by accumulation ratios equal to 1.28 (once daily administration) and 1.73 (twice daily administration). Tianeptine and MC5 rapidly appeared in brain tissue but at concentrations less than those observed in plasma. Peak concentrations of tianeptine in brain were higher than those of MC5. A very low penetration of tianeptine and MC5 into erythrocytes was observed.