Ticarcillin and piperacillin adsorption on to polyethersulfone haemodiafilter membranes in an ex-vivo circuit

Abstract

Objectives: To describe the adsorption of ticarcillin and piperacillin on to polyethersulfone (PES) membranes using the recirculation function on an ex-vivo renal replacement circuit. Methods: Low (4–8 mg) or high (35–45 mg) doses of ticarcillin and low (4–8 mg) or high (70–80 mg) doses of piperacillin were added to 1 L of human blood-crystalloid mixture and circulated around an ex-vivo modified continuous renal replacement therapy machine at three different blood flow settings (150, 300 and 450 mL/min). Plasma samples were collected from the pre-filter port of the haemodiafilter circuit at consecutive timepoints for a total duration of 4 h. Plasma samples were measured using a validated ultra high performance liquid chromatography–tandem mass spectrometry method. Results: Eighty-one samples including both drugs were collected from 18 experimental runs. Overall, the percentage of piperacillin adsorption for the low and high doses ranged from 21.3% to 27.1% and from 11.5% to 23%, and the percentage of ticarcillin adsorption for the low and high doses ranged from 4.2% to 14.3% and from 3.7% to 15.1%, respectively. The low dose of piperacillin consistently yielded more than 20% adsorption of dose for all blood flow rates. This decreased with high blood flow rates when the high dose of piperacillin was used. Ticarcillin generally displayed ≤5% adsorption, with the exceptions being the high dose at 150 mL/min and the low dose at 300 mL/min, which displayed ~15% adsorption. Conclusions: Adsorption of both drugs tended to be higher at the lowest blood flow rates and lowest doses. This is likely due to saturation of parts of the filter that have a chemical attraction to both piperacillin and ticarcillin. At low doses at all three blood flow rates, piperacillin demonstrated >20% adsorption, whereas ticarcillin tended to have low rates (up to ~≤15%) of adsorption on to PES membrane filters.