Intravenous lipid therapy (ILE) is used to treat neurotoxicosis in companion animals, but clinical evidence for in vivo xenobiotic partitioning and benefit remains limited. This study evaluated associations between the log n-octanol/water partition coefficient (log P), in vivo plasma partitioning, and early neurological outcome. In this case series from eight veterinary hospitals, dogs and cats with suspected neurotoxicosis received ILE. Blood collected before and at the end of infusion was separated into lipid and aqueous fractions and analyzed by gas chromatography–mass spectrometry. Log P values were retrieved from PubChem. Outcome (improvement vs. no-improvement) was the change from ILE-start to 4–6 h later. Thirty-four cases were analyzed (27 dogs and seven cats; 17 different xenobiotics were identified). At the end of infusion, xenobiotic lipid fraction concentrations exceeded aqueous concentrations in 28/34 cases, and log P did not correlate with the lipid-to-aqueous ratio. Improvement occurred in 14/34 animals and was associated with higher lipid-to-aqueous xenobiotic ratios (geometric mean ratio 5.7; 95% CI 1.73–19.05; p = 0.007). Overall, in vivo lipid sequestration was frequent and was associated with early neurological improvement, whereas log P alone did not predict partitioning or outcome.
Voorhorst et al. (Tue,) studied this question.