Lack of removal of calcitriol during hemodialysis procedures

In this study, an in vitro study with blood was performed to determine whether calcitriol (Calcijex) is either bound or removed from blood by dialyzer circuits. The study utilized five different dialyzers, each with a widely varying membrane type, and standard dialysate blood lines. One liter of fresh whole bovine blood was injected with 0.6 microg calcitriol and was dialyzed against 5 L of acetate-based dialysate for 180 min. By measurement of changes in blood and dialysate levels of calcitriol, there was no evidence of any calcitriol dialytic clearance and no evidence of calcitriol binding to the blood side components for any of the dialysis circuits. The results of this study indicate that calcitriol can be injected intravenously at any time during a dialysis procedure, without significant removal of the drug from the blood by dialyzer clearance or by binding to materials in the dialyzer circuit.