Determination of pterostilbene in rat plasma by a simple HPLC-UV method and its application in pre-clinical pharmacokinetic study.

A simple HPLC-UV method was developed and validated for the quantification of pterostilbene (3,5-dimethoxy-4'-hydroxy-trans-stilbene), a pharmacologically active phytoalexin in rat plasma. The assay was carried out by measuring the UV absorbance at 320 nm. Pterostilbene and the internal standard, 3,5,4'-trimethoxy-trans-stilbene eluted at 5.7 and 9.2 min, respectively. The calibration curve (20-2000 ng/mL) was linear (R(2)> 0.997). The lower limits of detection and of quantification were 6.7 and 20 ng/mL, respectively. The intra- and inter-day precisions in terms of RSD were all lower than 6%. The analytical recovery ranged from 95.5 +/- 3.7 to 103.2 +/- 0.7% while the absolute recovery ranged from 101.9 +/- 1.1 to 104.9 +/- 4.4%. This simple HPLC method was subsequently applied in a pharmacokinetic study carried out in Sprague-Dawley rats. The terminal elimination half-life and clearance of pterostilbene were 96.6 +/- 23.7 min and 37.0 +/- 2.5 mL/min/kg, respectively, while its absolute oral bioavailability was 12.5 +/- 4.7%. Pterostilbene appeared to have better pharmacokinetic characteristics than its natural occurring analog, resveratrol.