Prediction of combination effect of quinidine on the pharmacokinetics of tipepidine using a physiologically based pharmacokinetic model

Abstract

1. Tipepidine, an antitussive drug, has been reported to have central pharmacological effects and can be expected to be safely repositioned as treatment for psychiatric disorders. Since tipepidine requires three doses per day, development of a once-daily medication would be highly beneficial. Previously, we reported that combination use with quinidine, a CYP2D6 inhibitor, prolongs the half-life of tipepidine in chimeric mice with humanised liver.

2. In this study, to predict this combination effect in humans, a physiologically based pharmacokinetic (PBPK) model was developed, and quantitative simulation was conducted. The simulation results indicated that concomitant administration of tipepidine with quinidine increased the predicted C_max, AUC, and t_1/2 of tipepidine in the Japanese population by 3.4-, 6.6-, and 2.4-fold, respectively.

3. Furthermore, to compare with another approach that aims to prolong the half-life, the PK profile of tipepidine administered in hypothetical extended-release form was simulated. Extended-release form was predicted to be more influenced by CYP2D6 genotype than combination with quinidine, and the predicted plasma exposure was markedly increased in poor metabolizers, potentially leading to adverse effects.

4. In conclusion, quantitative simulation using the PBPK model suggests the feasibility of the safe repositioning of tipepidine as a once-daily medication in combination with quinidine.

Keywords:

• Tipepidine
• drug repositioning
• CYP2D6
• drug interaction
• physiologically based pharmacokinetic modelling

Disclosure statement

The authors declare no conflict of interest. Shun Hayashi, Hiroko Kawaguchi, Takao Watanabe, Izuru Miyawaki are employees of Sumitomo Pharma Co., Ltd.

Data availability statement

The data that support the findings of this study are available upon reasonable request.

Additional information

Funding

The author(s) reported there is no funding associated with the work featured in this article.