Pharmacokinetics Toxicokinetics

Limited pharmacokinetic data are available because saw palmetto is a mixture of various compounds (29). With respect to absorption of saw palmetto components, a mean peak plasma drug concentration of 2.6 mg/L of the "second component" with a high-performance liquid chromatography retention time of 26.4 minutes was measured in 12 healthy young men after a single oral dose of 320 mg of saw palmetto. The time to peak concentration occurred 1.5 hours after administration (30). A 640-mg rectal dose of saw palmetto extract produced a peak of 2.6 ^g/mL occurring 3 hours after the dose (31). Rat studies indicate that prostate concentrations are higher than those achieved in other genitourinary tissues or in the liver (29) suggesting selective distribution to tissues of interest. The elimination half-life of the "second component" discussed previously was 1.9 hours and the mean area under the concentration vs time curve (AUC) was 8.2 mg/(L-hour) after a single oral dose of 320 mg (30). The AUC of the "second component" produced by a 640-mg rectal dose of saw palmetto extract was 10 mg/(L-hour), and plasma levels were detectable up to 8 hours postdose (31).

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