Effects of multidose simvastatin co-administration on pharmacokinetic profile of apatinib in rats by UPLC-MS/MS

A Drug-Drug Interaction Study to Evaluate the Impact of Simvastatin and Itraconazole on Erlotinib Pharmacokinetics in Rats by UPLC-MS/MS

Aim

The goal of our study was to investigate the effects of single-dose simvastatin and itraconazole application on the pharmacokinetics of erlotinib in rats.

Methods

Twenty-one male Sprague-Dawley rats were randomly divided into 3 groups, including erlotinib combined with simvastatin, erlotinib combined with itraconazole and erlotinib alone groups. The rats were given a single dose of 2 mg/kg simvastatin, 15 mg/kg itraconazole or 0.5% sodium carboxymethyl cellulose followed by 12 mg/kg erlotinib. The concentration of erlotinib in rat plasma was determined by UPLC-MS/MS. As internal standard, tinidazole was used for chromatographic analysis on the Kinetex C18 column (100×2.1 mm, 2.6 μm).

Results

Erlotinib was validated in the calibration range of 5-1000 ng/mL. The lower limit of quantification (LLOQ) was 5 ng/mL. The inter- and intra-day precisions for erlotinib were less than 10.56%, and the accuracies were in the range of 98.61-104.99%. The validated UPLC-MS/MS method was successfully applied to this study. Compared with the erlotinib alone group, the values of AUC0-t, AUC0-∞, Cmax, Vz/F and t1/2 in the simvastatin group showed no statistical differences among pharmacokinetic parameters (P>0.05). However, the values of AUC0-t, AUC0-∞ and Cmax, in the itraconazole group were approximately 1.32-fold, 1.32-fold and 1.34-fold higher, and the CL/F was lower than those in the erlotinib alone group; the difference was statistically significant (P<0.05).

Conclusion

Simvastatin had no significant effect on the pharmacokinetics of erlotinib, whereas co-administration of itraconazole considerably increased the exposure of erlotinib. Therefore, we should pay more attention to the potential drug-drug interaction to ensure safety in cancer patient treatment.

Investigation of the Inhibitory Effect of Simvastatin on the Metabolism of Lidocaine Both in vitro and in vivo

Background

Lidocaine has cardiovascular and neurologic toxicity, which is dose-dependent. Due to CYP3A4-involved metabolism, lidocaine may be prone to drug-drug interactions.

Materials and Methods

Given statins have the possibility of combination with lidocaine in the clinic, we established in vitro models to assess the effect of statins on the metabolism of lidocaine. Further pharmacokinetic alterations of lidocaine and its main metabolite, monoethylglycinexylidide in rats influenced by simvastatin, were investigated.

Results

In vitro study revealed that simvastatin, among the statins, had the most significant inhibitory effect on lidocaine metabolism with IC₅₀ of 39.31 µM, 50 µM and 15.77 µM for RLM, HLM and CYP3A4.1, respectively. Consistent with in vitro results, lidocaine concomitantly used with simvastatin in rats was associated with 1.2-fold AUC_(0-t), 1.2-fold AUC_(0-∞), and 20%-decreased clearance for lidocaine, and 1.4-fold C_max for MEGX compared with lidocaine alone.

Conclusion

Collectively, these results implied that simvastatin could evidently inhibit the metabolism of lidocaine both in vivo and in vitro. Accordingly, more attention and necessary therapeutic drug monitoring should be paid to patients with the concomitant coadministration of lidocaine and simvastatin so as to avoid unexpected toxicity.