Liposome supported peritoneal dialysis in rat amitriptyline exposure with and without intravenous lipid emulsion

Liposome supported peritoneal dialysis is a recently described technique which may eventually be applicable in the clinical scenario of the intoxicated patient. We evaluated the hypothesis that intravenous injection of lipid emulsion (ILE) would augment acidic pH gradient liposome supported peritoneal dialysis (LSPD). Orogastrically amitriptyline dosed rats were treated with either Sodium bicarbonate (NaHCO3) intravenously and standard intraperitoneal dialysate (Group A); NaHCO3 intravenously and LSPD (Group B); or ILE and LSPD (Group C). The primary endpoint was dialysate amitriptyline concentration after a 60 min dwell. Secondary analysis included an estimate of extraction ratio for peritoneal blood flow (ERs). There were significantly higher intraperitoneal concentrations of amitriptyline and ERs in the two groups treated with LSPD (Group B, p = 0.02, Group C, p < 0.01 vs. Group A). There was no observed effect for ILE on intraperitoneal amitriptyline concentration or ERs (p > 0.20). LSPD increased the amitriptyline concentration in peritoneal dialysate. No further increase was demonstrated with ILE. This may be either because such an effect is absent, or type II error. Exploratory analysis suggests LSPD may be driven by total rather than free drug concentrations.