Is aspirin a substrate of MDR1/P-glycoprotein?

Abstract

1. Aspirin (acetyl salicylic acid) is widely used co-medication in patients with cardiovascular and cerebrovascular diseases. Given the prevalence of acetyl salicylic acid’s use as a co-medication and conflicting reports in the literature on it being a substrate of P-glycoprotein (P-gp). There is a potential risk for its interaction with compounds with P-gp liability, therefore, we have conducted a detailed investigation to determine substrate potential of acetyl salicylic acid towards P-gp.

2. We observed significantly lower cellular uptake of acetyl salicylic acid in MDR1 transfected LLC-PK1 cells compared to LLC-PK1 wild-type (WT) cells, however, the in vitro efflux of acetyl salicylic acid in MDR1 transfected LLC-PK1 cells was not inhibited by known inhibitors under various conditions. Acetyl salicylic acid did not show active asymmetrical transport across MDR1 transfected LLC-PK1 cells compared to LLC-PK1-WT cells in transwell assay. Moreover, no difference in plasma and brain exposure of acetyl salicylic acid and its metabolite salicylic acid was observed between FVB-WT and Mdr1a/b knockout (KO) mice.

3. Taken together, our findings indicate that acetyl salicylic acid is not a substrate of P-gp.

Keywords:

• Aspirin
• acetyl salicylic acid
• P-glycoprotein
• MDR1
• DDI

Acknowledgements

The authors thank Marc Fancher and Nicole Harbaugh for in life portion of the mice study and Jian Wang for coordinating bioanalysis of in vivo study samples. Thanga Mariappan is acknowledged for supervision of work conducted at Syngene International.

Disclosure statement

The authors report no conflict of interest.