Validated LC/MS/MS assay for curcumin and tetrahydrocurcumin in rat plasma and application to pharmacokinetic study of phospholipid complex of curcumin

To study pharmacokinetic properties of curcumin, a fast sensitive assay method was developed to determine curcumin and its metabolite tetrahydrocurcumin in rat plasma. The assay was based on tandem mass spectrometry detection (LC/MS/MS). Salbutamol was used as the internal standard (IS). The method had the lower limit of quantitation (LLOQ) of 0.5 ng/ml in rat plasma, which corresponds to 2.5 pg for the 5 μl injection volume. Good linearity was got to 500 ng/ml. The precision, accuracy, recovery and applicability were found to be adequate for pharmacokinetic studies.Phospholipid complex of the natural compound curcumin was prepared in order to improve its bioavailability. Complex formation resulted in an obvious increase in bioavailability of curcumin in rat in vivo according to the assay by above LC/MS/MS method.