SIMULTANEOUS DETERMINATION OF TOLBUTAMIDE AND ITS METABOLITE HYDROXYTOLBUTAMIDE IN RAT PLASMA BY LC-MS

Development of a simple and rapid UPLC-MS/MS method for determination of 8-deacetyl-yunaconitine in rat plasma and its application to pharmacokinetics

In this paper, UPLC-MS/MS was used to determine 8-deacetyl-yunaconitine in the plasma of rats after oral and intravenous administration. Six rats were orally (po) administered 8-deacetyl-yunaconitine (5 mg/kg), while another six rats were intravenously (iv) administered the drug (0.1 mg/kg). A standard curve of known concentrations of 8-deacetyl-yunaconitine in rat plasma was generated over the range of 0.3-600 ng/mL. The intra-day and inter-day precision of 8-deacetyl-yunaconitine in rat plasma was lower than 15 %, while the accuracy ranged between 97.7 % and 105.5 %. In addition, the matrix effect ranged between 95.3 % and 105.6 %, while the recovery was greater than 82.8 %. This determined method was then applied in measuring the pharmacokinetics of 8-deacetyl-yunaconitine in rats. The AUC_(0-t) values were 73.0 ± 24.6 and 1770.0 ± 530.6 ng/mL h for intravenous and oral administration, respectively, and the bioavailability was 48.5 %. The half-life (t_1/2) was determined to be 4.5 ± 1.7 h and 3.2 ± 0.7 h for intravenous and oral administration, respectively, indicating that the metabolism of the xenobiotic was quick in the rats.