Translational aspects of cytochrome P450-mediated drug-drug interactions: A case study with clopidogrel

Inhibitory effects of the main metabolites of Apatinib on CYP450 isozymes in human and rat liver microsomes

PURPOSE

The inhibitory effect of Apatinib on cytochrome P450 (CYP450) enzymes has been studied. However, it is unknown whether the inhibition is related to the major metabolites, M1-1, M1-2 and M1-6.

METHODS

A 5-in-1 cocktail system composed of CYP2B6/Cyp2b1, CYP2C9/Cyp2c11, CYP2E1/Cyp2e1, CYP2D6/Cyp2d1 and CYP3A/Cyp3a2 was used in this study. Firstly, the effects of APA and its main metabolites on the activities of HLMs, RLMs and recombinant isoforms were examined. The reaction mixture included HLMs, RLMs or recombinant isoforms (CYP3A4.1, CYP2D6.1, CYP2D6.10 or CYP2C9.1), analyte (APA, M1-1, M1-2 or M1-6), probe substrates. The reactions were pre-incubated for 5 min at 37 °C, followed by the addition of NAPDH to initiate the reactions, which continued for 40 min. Secondly, IC50 experiments were conducted to determine if the inhibitions were reversible. The reaction mixture of the "+ NADPH Group" included HLMs or RLMs, 0 to 100 of μM M1-1 or M1-2, probe substrates. The reactions were pre-incubated for 5 min at 37 °C, and then NAPDH was added to initiate reactions, which proceeded for 40 min. The reaction mixture of the "- NADPH Group" included HLMs or RLMs, probe substrates, NAPDH. The reactions were pre-incubated for 30 min at 37 °C, and then 0 to 100 μM of M1-1 or M1-2 was added to initiate the reactions, which proceeded for 40 min. Finally, the reversible inhibition of M1-1 and M1-2 on isozymes was determined. The reaction mixture included HLMs or RLMs, 0 to 10 μM of M1-1 or M1-2, probe substrates with concentrations ranging from 0.25Km to 2Km.

RESULTS

Under the influence of M1-6, the activity of CYP2B6, 2C9, 2E1 and 3A4/5 was increased to 193.92%, 210.82%, 235.67% and 380.12% respectively; the activity of CYP2D6 was reduced to 92.61%. The inhibitory effects of M1-1 on CYP3A4/5 in HLMs and on Cyp2d1 in RLMs, as well as the effect of M1-2 on CYP3A in HLMs, were determined to be noncompetitive inhibition, with the Ki values equal to 1.340 μM, 1.151 μM and 1.829 μM, respectively. The inhibitory effect of M1-1 on CYP2B6 and CYP2D6 in HLMs, as well as the effect of M1-2 on CYP2C9 and CYP2D6 in HLMs, were determined to be competitive inhibition, with the Ki values equal to 12.280 μM, 2.046 μM, 0.560 μM and 4.377 μM, respectively. The inhibitory effects of M1-1 on CYP2C9 in HLMs and M1-2 on Cyp2d1 in RLMs were determined to be mixed-type, with the Ki values equal to 0.998 μM and 0.884 μM. The parameters could not be obtained due to the atypical kinetics of CYP2E1 in HLMs under the impact of M1-2.

CONCLUSIONS

M1-1 and M1-2 exhibited inhibition for several CYP450 isozymes, especially CYP2B6, 2C9, 2D6 and 3A4/5. This observation may uncover potential drug-drug interactions and provide valuable insights for the clinical application of APA.

Influence of Gegenqinlian decoction on pharmacokinetics and pharmacodynamics of saxagliptin in type 2 diabetes mellitus rats

Gegenqinlian decoction (GQD) is a classic prescription of traditional Chinese medicine (TCM), which originated from Shanghanlun. The combination of GQD and hypoglycemic drugs (saxagliptin, Sax, metformin) is often used to treat Type 2 diabetes mellitus (T2DM) in TCM clinics. However, the herb-drug interactions (HDIs) between GQD and hypoglycemic drugs are still unclear. In order to determine the safety of the combination, we assessed the influences of GQD on the pharmacokinetics and pharmacodynamics of Sax in T2DM rats. The plasma concentration of Sax (5 mg/kg) pretreated with GQD (freeze-dried powder, 1.35 g/kg) or not was determined by high-performance liquid chromatography (HPLC), and pharmacokinetics parameters were calculated. The influence of GQD on the pharmacodynamics of Sax was investigated by detecting the levels of weight, (see abbreviations list) OGTT, TC, TG, LDL-C, HDL-C, FBG, FINS, HOMA-IR, QUICKI, AST, ALT, and the liver coefficient. The Cmax , AUC0-t ,and AUC0-∞ of Sax increased significantly in the combination group whether in normal or T2DM rats. The results of pharmacodynamics showed that the weight of rats in each treatment group increased. FBG, TC, TG, LDL-C, and HOMA-IR decreased, HDL-C, FINS, and QUICKI increased significantly (p < 0.05) compared with the model control group. The result showed that the combination of GQD and Sax could not only improve the hypoglycemic effect but also increase the plasma exposure of Sax. The potential HDIs between GQD and Sax should be taken into consideration in clinics. Moreover, for the complexity of the human compared with experimental animals, as well as genetic differences, the in-depth study should be carried out to assess the uniformity of the pharmacokinetics and pharmacodynamics between rats and humans.