PHARMACOKINETICS AND TESTOSTERONE SUPPRESSION OF A SINGLE-DOSE OF POLYESTRADIOL PHOSPHATE (ESTRADURIN(R)) IN PROSTATIC-CANCER PATIENTS

The pharmacokinetics and endocrine effects of polyestradiol phosphate (PEP; Estradurin(R)) were studied by determination of the concentratio ns of estradiol (E(2)), unconjugated (E(1)) and total estrone (tE(1); greater than or equal to 85% estrone sulfate), and testosterone in ser um from 11 prostatic cancer patients after administration of a single intramuscular injection (320 mg). After injection of PEP, serum concen trations of E(2), E(1), and tE(1) increased during 2-3 weeks. Thereaft er serum E(2) declined monophasically with a mean half-life of 70 days . The elimination of E(1) and tE(1) seemed to be governed by the forma tion of E(2). The testosterone concentration decreased inversely to th e raising E(2) level and reached castration levels within 3 weeks and remained at this level for about 2 weeks, whereafter it increased inve rsely to the decreasing E(2) concentrations. (C) 1996 Wiley-Liss, Inc.