Determination of (E)-3,5,4′-Trimethoxystilbene in Rat Plasma by LC with ESI-MS

Abstract

(E)-3,5,4′-trimethoxystilbene (BTM-0512) is a resveratrol analog with a variety of pharmacological action, including anti-cancer properties, anti-allergic activity, estrogenic activity, antiangiogenic activity, and vascular-targeting activity against microtubule-destabilization. There is, however, no validated analytical method for quantification of (E)-3,5,4′-trimethoxystilbene in biological matrices, so pharmacokinetic data and suitable methods for determination of the compound in plasma are currently lacking. A rapid and sensitive liquid chromatographic–mass spectrometric method for determination of (E)-3,5,4′-trimethoxystilbene in rat plasma, using carbamazepine as internal standard, has been developed and validated. Plasma samples were treated with acetonitrile to precipitate proteins. Samples were then analyzed by HPLC on a 250mm × 4.6 mm i.d., 5-μm particle, C₁₈ column with methanol–water, 80:20 (v/v), containing 10 mm ammonium acetate and 0.2% formic acid (pH 3.0), as mobile phase, delivered at 0.85 mL min⁻¹. A single-quadrupole mass spectrometer with an electrospray interface operated in selected-ion monitoring mode was used to detect [M + H]⁺ ions at m/z 271.3 for (E)-3,5,4′-trimethoxystilbene and m/z 237.5 for the internal standard. (E)-3,5,4′-trimethoxystilbene and the internal standard eluted as sharp, symmetrical peaks with retention times of 8.9 and 4 min, respectively. Calibration plots for (E)-3,5,4′-trimethoxystilbene in rat plasma at concentrations ranging from 0.01 to 5.0 μg mL⁻¹ were highly linear. Intra-day and inter-day precision, as RSD, was <12.9%, and accuracy was in the range 94.8–104.7%. The limit of detection in plasma was 0.005 μg mL⁻¹. The method was successfully used to determine the concentration of (E)-3,5,4′-trimethoxystilbene after oral administration of 86 mg kg⁻¹ of the drug to Sprague–Dawley rats and can be used to investigate the pharmacokinetics of the compound.