Study On Pharmacokinetic Interaction Between Hawthorn Flavonoids And Ezetimibe

Purpose: Hyperlipidemia and its associated cardiovascular diseases have been becoming a major threat for health with the improvement of living level.To the best of our knowledge,it is difficult to achieve satisfactory therapeutic effect for any one kind of medicine because of the complexity of the hyperlipidemia treatment.Thus,it is necessary for two or more kinds of medicines in combined use for the treatment of hyperlipidemia.Ezetimibe is a novel lipid-lowering medicine which exhibited potent inhibitory effect on the uptake of cholesterol and phytosterol in small intestinal.However,the low solubility of ezetimibe exerts an unfavorable effect on its anti-hyperlipidemia efficacy.Hawthorn,a drug-eating homologous plants,showed beneficial effect on lowering the level of cholesterol and triglycerides and attenuating the atherosclerosis progression.Hawthorn has become increasingly popular among those patients with hyperlipidemia.The combination with clinical hypolipidemic drugs raised the risk of occurrence of drug-drug interaction.It was reported that flavonoids in hawthorn played a key role in the treatment of hyperlipidemia.Thus,the aim of this paper was to investigate the pharmacokinetic interaction and the underlying mechanisms between hawthorn flavonoids and ezetimibe,which will provide rational use of them in clinical practice.Methods:1.Effect of hawthorn flavonoids on the pharmacokinetics of ezetimibe:UPLC-MS method was estabolished for the determination of ezetimibe in rat plasma samples.The pharmacokinetic experiments were carried out to study the effect of hawthorn flavonoids on the pharmacokinetics of ezetimibe after simutaneous administration and long-term administration?15 days?.2.Effect of hawthorn flavonoids on the intestinal absorption of ezetimibe: HPLC method was estabolished for the determination of ezetimibe.The effect of hawthorn flavonoids on the intestinal absorption of ezetimibe were investigated by rat intestinal perfusion model.3.Effect of hawthorn flavonoids on the metabolism of ezetimibe in vitro: HPLC method was estabolished for the determination of ezetimibe in rat liver microsome.The rat liver microsome incubation system was applied to investigate the effect of hawthorn on the metabolism of ezetimibe.Results:1.The results of pharmacokinetics of ezetimibe were listed as followings:?1?the main pharmacokinetic parameters of ezetimibe showed as follow: t1/2 and Tmax were8.39±1.25 h,2.67±1.25 h,respectively.While AUC0-36 h and Cmax were 23.22±1.03ng/mL*h ? 2.00 ± 0.96 ng/mL.After simutaneous administration of hawthorn flavonoid mixture,t1/2 and Tmax of ezetimibe were 9.64±2.59 and 2.67±1.15 h,which prolonged by 14.9%?P>0.05?and 0%?P>0.05?respectively;while AUC0-36 h and Cmax were 28.65±0.72 ng/mL*h and 3.23±1.48 ng/mL,which increased by23.5%?P>0.05?and 61.5%?P>0.05?,respectively.?2?After Co-simutaneous administration of lueolin,t1/2 and Tmax of ezetimibe were 11.03± 1.58 and 4.00± 0.10 h,which prolonged by31.5%?P>0.05?and 49.8%?P>0.05?respectively;while AUC0-36 h and Cmax were24.45±6.67 ng/mL*h and 3.18±1.17 ng/mL,which increased by 5.30%?P>0.05?and59.0%?P>0.05?,respectively.?3?After simutaneous administration with quercetin and catechins,t1/2 and Tmax of ezetimibe were prolonged to some extent,while no significant diference was observed about Cmax and AUC0-36 h.2.The results of pharmacokinetics of ezetimibe were listed as followings:?1?After long-term administration of hawthorn flavonoid mixture,t1/2 and Tmax of ezetimibe were 9.24±2.15 and 4.67±1.15 h,which prolonged by 10.1%?P>0.05?and 74.9%?P<0.05?respectively;while AUC0-36 h and Cmax were 38.99 ± 8.48 ng/mL*h and5.48 ± 1.87 ng/mL,which increased by 67.9%?P<0.05?and 174%?P<0.05?,respectively.?2?After long-term administration of lueotin,t1/2 and Tmax of ezetimibe were 8.48±0.71 and 4.00±0.95 h,which prolonged by 1.07%?P>0.05?and 49.8%?P>0.05?respectively;while AUC0-36 h and Cmax were 30.79 ± 4.00 ng/mL*h and3.33 ± 0.95 ng/mL,which increased by 32.6%?P>0.05?and 66.5%?P>0.05?,respectively.?3?After long-term administration with quercetin and catechins,t1/2 and Tmax of ezetimibe were prolonged to some extent,while no significant diference was observed about Cmax and AUC0-36 h.3.Results of the in situ perfusion study showed that the apparent absorption reaction constant and the percent conversion rate of absorption of ezetimibe were0.698±0.12 h^-1,0.278±0.07 h^-1,respectively.Compared with luteolin,quercetin and catechins were 0.711±0.21,0.715±0.18,0.708±0.20 and 0.701±0.17 h^-1?P>0.05?,respectively,and the percent conversion rate were 0.279 ± 0.07,0.307 ± 0.085,0.282±0.075,0.299±0.071 h^-1,respectively?P>0.05?.4.The optimal conditions for the phase-?metabolism were listed as followings:the incubation time was 40 min,protein concentration was 1.0 mg/mL,and ezetimibe concentration was 30 ?mol/L.Based on the Michaelis-Menten equation,Km,Vmax and Clint were 46.93 ?mol/L,2.579 ?mol/min/mg protein,and 0.093 L/min/mg protein.As for the phase ? metabolism of ezetimibe,the optimal incubation conditions were 20 min,0.4 mg/mg and 40 ?mol/L,while Km,Vmax and Clint were26.07 ?mol/L,2.762 ?mol/min/mg protein,0.095 L/min/mg protein,respectively.5.The IC₅₀ values of luteolin,quercetin,catechins and flavonoid mixture on the phase?metabolism of ezetimibe were 6.76 ?mol/L,5.35 ?mol/L,12.82 ?mol/L,2.06?g/mL.The Ki values of luteolin,quercetin and flavonoid mixture were 11.16 ?mol/L,21.72 ?mol/L and 3.40 ?g/mL,respectively.The IC₅₀ values on the phase ?metabolism of ezetimibe were 21.07 ?mol/L,47.49 ?mol/L,52.70 ?mol/L,50.96?g/mL.And Ki values were 53.00 ?mol/L,54.50 ?mol/L,55.19 ?mol/L and 57.34?g/mL,respectively.Conclusion:1.Flavonoid mixture,luteolin,quercetin and catechins showed a certain inprovement on the absorption of ezetimibe?P>0.05?.2.The luteolin and quercetin in hawthorn showed a moderate inhibitory effect on the phase I metabolism of ezetimibe,catechins showed a weak inhibitory effect,and the flavonoid mixture showed a strong inhibitory effect.Whereas the three compounds and their mixtures had a weak inhibitory effect on the phase II metabolism of ezetimibe.3.Hawthorn flavonoids exerted effect on the pharmacokinetic property of ezetimibe via promoting the intestinal absorption and inhibiting the liver metabolism.