[Pharmacokinetic studies on THP-ADM (tetrahydropyranyl adriamycin)]

THP-ADM is a new antitumor agent which belongs to the anthracycline family. This agent has shown a high therapeutic index compared with the mother compound, Adriamycin, in preclinical and clinical studies. This time, a pharmacokinetic study of THP-ADM was performed and the following characteristics of this agent were clarified. A short t 1/2 alpha was noted in comparison with that of Adriamycin in a 3-compartment open model. Leukocyte concentration with THP-ADM was much higher than that of plasma of red blood cells. Renal excretion over 48 hours was 9% and biliary excretion over the same period was 20%. High THP-ADM and low Adriamycin tissue concentrations were revealed in all tissues excluding the liver. In liver tissue, a high concentration of Adriamycin and a low concentration of THP-ADM was observed. A small amount of Adriamycin was noted in the plasma following THP-ADM administration. This was probably related to the small amount of existing Adriamycin in THP-ADM or conversion of THP-ADM to Adriamycin in the liver tissue, or both. Poor penetration of THP-ADM into the third space was noted.