Pharmacokinetic profile and oral bioavailability of Kaurenoic acid from Copaifera spp. in rats.

Kaurenoic acid (KA) is a kaurane diterpene found in several medicinal plants that displays biological activities, such as anti-inflammatory, smooth muscle relaxant and hypotensive response. However, there are no pharmacokinetic data available about this molecule. The purpose of the study was to determine the pharmacokinetic profile and the oral bioavailability of KA in rats. Wistar rats submitted to jugular vein cannulation received 50 mg/kg of KA by intravenous or oral route. The implanted cannula allowed intravenous administration and serial blood collection along 10 h. Analytical quantification was performed by reversed phase HPLC-UV and mobile phase composed by acetonitrile:acidified water (70:30 v/v). The validated analytical method showed precision, accuracy, robustness, reliability and linearity between 0.75 and 100 µg/mL. KA administered intravenously showed a linear and two-compartment kinetic behavior at the tested dose. The following pharmacokinetic parameters were determined: Cmax = 22.17 ±â€¯1.65 mg/L; V = 14.53 ±â€¯1.47 L/kg; CL = 17.67 ±â€¯1.50 mL/min/kg; AUC0-∞ = 2859.65 ±â€¯278.42 mg·min/L, K = 0.073 ±â€¯0.005 h-1 and t1/2ß = 9.52 ±â€¯0.61 h. Oral treatment did not provide detectable plasma levels of KA, avoiding the determination of its bioavailability.