AbstractA rapid method for the determination of iopanoic acid (IOP) in dog plasma utilizing a Hisep column was developed. A mobile phase of 12% methanol, 88% 0.05Mphosphate buffer pH 3.4 yielded ak′ of 8.5 with no interference from proteins present in plasma. Recoveries of IOP from spiked plasma ranged from 97% to 103% at 270 μmol/L and 1.75 mmol/L respectively. Replication was ±2.8% at 1.75 mmol/L and ±6% at 21 μmol/L. A method utilizing 2,4,6‐triiodobenzoic acid as internal standard was also developed for com