Abstract: AIM:Trigonelline(Tr) is the second most abundant alkaloid in coffee beans.This study developed an assay combining hydrophilic interaction chromatography with ultra performance liquid chromatography(HILIC-UPLC) for the quantification of Tr in rat plasma to determine its pharmacokinetic behavior.METHODS:After the administration of Tr by gavage as well as intravenous injection and that of methanol extract of coffee beans(MECB) orally,blood samples from the experimental rats were analyzed using the HILIC-UPLC assay.Pharmacokinetic parameters were determined using the standard non-compartmental method and calculated using Practical Pharmacokinetic Program Version 87/97.RESULTS:The HILIC-UPLC assay was validated with the linear range of 0.12-100 gmL-1 and a lower limit of quantitation of 0.12 gmL-1.Its accuracy,precision,recovery,and stability were within acceptable limits.The AUC(0-)(where AUC is the area under the plasma concentration-time curve) values were determined to be(4 066.831 244.41) and(3 544.29908.80) mingmL-1 after Tr was orally and intravenously administered,respectively.It was(4 566.751 435.64) mingmL-1 after MECB was orally administered.The absolute bioavailability of Tr alone reached 57.37%,whereas that of Tr in MECB was 64.42%.The relative bioavailability of the alkaloid was 112.29%.CONCLUSIONS:The HILIC-UPLC assay for Tr determination is simple and accurate,and also exhibits good reproducibility.The bioavailability of stand-alone Tr and that of Tr in MECB were both good.Tr alone and that in MECB orally administered did not exhibit any significant difference.