Increased plasma concentrations of an antidyslipidemic drug pemafibrate co-administered with rifampicin or cyclosporine A in cynomolgus monkeys genotyped for the organic anion transporting polypeptide 1B1

In vitro permeability and in vivo pharmacokinetics of pemafibrate were investigated in human intestinal and animal models untreated or pretreated with cyclosporine A or rifampicin to evaluate any drug interactions. Ratios of basal to apical apparent permeability (P_app) over apical to basal P_app in the presence of pH gradients decreased from 0.37 to 0.080 on rifampicin co-incubation, suggesting active transport of pemafibrate from basal to apical sides in intestinal models. Plasma concentrations of intravenously administered pemafibrate were enhanced moderately in control mice but only marginally in humanized-liver mice by oral pretreatment with rifampicin [an organic anion transporting polypeptide (OATP) 1B1 inhibitor] 1 h before the administration of pemafibrate. In three cynomolgus monkeys genotyped as wild-type OATP1B1 (2 homozygous and 1 heterozygous), oral dosing of cyclosporine A 4 h or rifampicin 1 h before pemafibrate administration significantly increased the areas under the plasma concentration–time curves (AUC) of intravenously administered pemafibrate by 4.9- and 7.4-fold, respectively. Plasma AUC values of three pemafibrate metabolites in cynomolgus monkeys were also increased by cyclosporine A or rifampicin. These results suggested that pemafibrate was actively uptaken in livers and rapidly cleared from plasma in cynomolgus monkeys; this rapid clearance was suppressible by OATP1B1 inhibitors.     

6种药物对有机阴离子转运多肽OATP1B1及其基因多态性A388G、T521C转运作用的影响

目的 研究6种药物对有机阴离子转运多肽OATP1B1及其基因多态性A388G、T521C转运作用的影响。方法 体外培养稳定高表达OATP1B1和OATP1B1基因多态性A388G、T521C的人胚肾细胞（HEK293）株,高表达空白载体（Mock）的HEK293细胞为空白对照,实时荧光定量PCR（qRT-PCR）法检测各转运体细胞中mRNA表达;放射性标记化合物³Hestrone sulfate作为转运底物、利福平作为阳性抑制剂验证各高表达细胞的转运活性;测定30 μmol·L^-1的达比加群、辛伐他汀、替格瑞洛、卡培他滨、多西他赛、依那普利对各细胞³H-estrone sulfate摄入活性的抑制作用,并依据抑制试验结果,进一步测定辛伐他汀、替格瑞洛、多西他赛对转运体细胞的半数抑制浓度（IC₅₀）。结果 HEK293细胞内导入的各种转运体基因都呈现良好的复制表达;OATP1B1、OATP1B1/A388G、OATP1B1/T521C对底物³H-estrone sulfate（5 μmol·L^-1）的转运活性分别为Mock细胞的39、49和48倍,30 μmol·L^-1利福平添加后,可将细胞的转运活性抑制到50%以下;辛伐他汀、替格瑞洛、多西他赛对OATP1B1的抑制作用较强,30 μmol·L^-1给药的转运活性分别为对照组的（40.09±1.95）%、（33.82±0.61）%、（45.08±0.22）%;辛伐他汀对OATP1B1、OATP1B1/A388G、OATP1B1/T521C的IC₅₀分别为14.2、＞100、＞100 μmol·L^-1,替格瑞洛的IC₅₀分别为19.1、68.4、＞100 μmol·L^-1,多西他赛的IC₅₀分别为17.6、22.9、19.3 μmol·L^-1。结论 OATP1B1基因多态性在一定程度上改变了抑制剂对转运体活性的影响程度。     

Quercetin‐3‐rhamnoglucoside (rutin) stimulates transport of organic anion compounds mediated by organic anion transporting polypeptide 2B1

Quercetin‐3‐rhamnoglucoside (rutin) has a wide spectrum of biochemical and pharmacological activities. Rutin is absorbed mainly in its unmetabolized form. Organic anion transporting polypeptide (OATP) 2B1 is a major uptake transporter in the intestine. Thus, it is important for the prevention of adverse events to understand drug interactions mediated by OATP2B1 in the absorption process. This study assessed the effect of rutin on transport by OATP2B1. Rutin stimulated the uptake of estrone‐3‐sulfate (E‐3‐S), taurocholic acid (TCA), cholic acid (CA) and rosuvastatin by OATP2B1, but not p‐coumaric acid or ferulic acid. The EC₅₀ of rutin for transport by OATP2B1 was 2.32 μm . The K_m value of E‐3‐S for OATP2B1 in the presence of rutin (9.21 μm ) was almost the same as that in the absence of rutin (8.53 μm ). On the other hand, the V_max of E‐3‐S transport by OATP2B1 in the presence of rutin (270 pmol/mg protein/min) was 1.2‐fold higher than that in the absence of rutin (218 pmol/mg protein/min). Moreover, the expression level of OATP2B1 on the cell membrane was increased by treatment with rutin for 5 min without alteration of the total OATP2B1 expression level. Moreover, the increase in the localization of OATP2B1 at the cell surface was detected by the immunocytochemistry. The stimulatory effect of rutin is a little weak but may affect the absorption of OATP2B1 substrates, because rutin is taken daily in foods and its intestinal concentration would reach the stimulatory range of OATP2B1. Copyright © 2014 John Wiley & Sons, Ltd.