ABSTRACT Ampicillin (AMP) is an organic anion drug widely used in clinical setting as a β‐lactam antibiotic. However, the specific transporter involved in mediating AMP transport remains unidentified. Thus, we investigated whether organic anion transporters1/3 (OAT1/3) mediate the renal transport of AMP in this study. Both rOAT1/OAT3 ( Slc22a6/Slc22a8 ) double‐knockout and wild‐type (WT) rats were administered AMP via intraperitoneal injection simultaneously. Following the knockout, a significant increase in AMP plasma concentration and the area under the plasma concentration–time curve (AUC) was observed, accompanied by a marked reduction in cumulative urinary excretion. OAT1/3‐overexpressing cell uptake experiments demonstrated that AMP is a substrate of OAT3, with a Michaelis–Menten constant ( K m ) of 138.6 μM and a maximum transport velocity ( V max ) of 80.43 pmol/mg protein/min. In conclusion, AMP was identified as a substrate of OAT3, rather than OAT1.
Liu et al. (Thu,) studied this question.