Pharmacokinetics of chelerythrine and its metabolite after oral and intramuscular administrations in pigs.

The objective of this study was to investigate the single- and multiple-dose pharmacokinetics of chelerythrine (CHE) and its metabolite, dihydrochelerythrine (DHCHE), after oral and IM administrations in pigs.Six crossbreed (Landrace × Large White) female pigs (7-8 weeks old; 24.1 ± 2.6 kg bw) administered oral and IM CHE at a dose of 0.1 mg/kg orally and intramuscularly in a cross-over design. Multiple oral administration was performed at 0.1 mg/kg a time, three times a day at 8-h intervals for three consecutive days. Blood samples were collected from the anterior vena cava and placed into heparinized centrifuge tubes before dosing (time 0 h) and at different times after oral and IM administrations. Pre-treatment plasma was analysed by high-performance liquid chromatography-tandem mass spectrometry.After IM administration, CHE and DHCHE rapidly reached peak concentrations ( C _max , 69.79 ± 15.41 and 3.47 ± 1.23 ng/mL) at 0.42 ± 0.13 and 0.33 ± 0.13 h, respectively. After single oral administration, CHE and DHCHE rapidly increased to reach C _max of 5.04 ± 1.00 and 1.21 ± 0.35 ng/mL at 1.83 ± 0.26 and 1.67 ± 0.26 h, respectively. The half-life ( T _1/2 ) was 2.03 ± 0.26 and 2.56 ± 1.00 h for CHE and DHCHE, respectively. After multiple oral administration, the average steady-state concentrations ( C _ss ) of CHE and DHCHE were 2.51 ± 0.40 and 0.6 ± 0.06 ng/mL, respectively.CHE is metabolized rapidly after a single oral administration, multiple daily doses and long-term use of CHE are recommended.