[Comparative studies on the pharmacokinetics between THP and adriamycin in the same patients]

The pharmacokinetic properties of THP and ADM were comparatively studied in the same patients with various cancers. The concentration of ADM in either plasma or blood cells was higher than that of THP from 5 minutes to 24 hours after administration. The metabolites of ADM such as aglycones were detected in plasma until 3 hours after administration, but these were never detected in blood cells. By contrast, the metabolites of THP were detected until 24 hours after administration. These results suggested that THP was metabolized in tissues and excreted into urine and that the rate of metabolism and excretion of THP was faster than that of ADM. Distribution volumes (V1, V2, and V3) of THP were larger than those of ADM. The above results strongly suggested that THP would be easily transferred into the tissues, but that in the case of slower transferring tissues with lower K13 values, ADM rather than THP would be easily transferred to the tissues. These pharmacokinetic properties suggested that the toxicity of THP might be diminished compared with that of ADM.