Preliminary study on the removal of protein-bound toxins using dilution and pH change

It is difficult to remove protein-bound uremic toxins (PBTx) by hemodialysis. In order to improve PBTx removal, we carried out an in vitro study to evaluate the effects of dilution and pH change on PBTx dissociation from albumin. Human plasma harvested by aphaeresis therapy was diluted by saline or isotonic aqueous NaHCO3. Free fractions of indoxyl sulfate and homocysteine were determined. As results, indoxylsulfate was easily dissociated from albumin by dilution and pH change. Higher dilution was more effective in increasing the free fraction of indoxylsulfate. However, homocysteine was not dissociated from albumin by these procedures. Development of an effective method is required for dissociation of each type of PBTx.