HPLC method with fluorescence detection for the determination of ligustilide in rat plasma and its pharmacokinetics

Few methods have been reported for the quantification of ligustilide (LIG) in biosamples: the pretreatment of the biological samples were laborious and time-consuming.

A high-performance liquid chromatographic method with fluorescence detection (HPLC-FLD) for the determination of LIG in rat plasma was developed and validated. Pharmacokinetics and bioavailability of LIG were determined by systematic investigation in Sprague-Dawley rats.

LIG was isolated from the volatile oil of Radix Angelica sinensis and further purified by silica gel column chromatography. Podophyllotoxin was used as an internal standard. The analytes were detected by using fluorescence detection at an excitation and emission wavelength of 290 and 395 nm during 0-4 min, and 336 and 453 nm during 4-14 min, respectively. LIG pharmacokinetics was studied in rats after oral and intravenous administration of 12.5, 25 and 50 mg/kg doses.

Two calibration curves (Y = 133.49 X - 14.27 (r = 0.9995), Y = 145.61 X + 13.76 (r = 0.9996)) were constructed in the range of 2.44-10,000 ng/mL for LIG with a lower limit of quantitation of 2.44 ng/mL. Both intra-day and inter-day precision were less than 6%. Accuracy ranged from 88.93 to 99.52%. The recovery ranged from 89.07 to 99.71%. The absolute bioavailability values were 71.36, 68.26 and 75.44% for oral doses of 12.5, 25 and 50 mg/kg, respectively.

The present HPLC-FLD method was rapid, sensitive and reliable. LIG was absorbed and eliminated rapidly in rat.