Experimental use of raffinose as an osmotic agent for peritoneal dialysis

Conventional glucose-based solutions for peritoneal dialysis fluids have been shown to raise problems of biocompatibility. We therefore evaluated the ultrafiltration capabilities of raffinose as an alternative osmotic agent in a non-uremic rat model. Animals were divided into four groups and injected intraperitoneally with solutions containing raffinose (4.5%, 345 mOsm/kg; 16.7%, 518 mOsm/kg) or glucose (1.5%, 346 mOsm/kg; 4.25%, 489 mOsm/kg). Data obtained from animals exposed to 16.7% raffinose were excluded because of precipitation of the osmotic agent. Low-osmolality raffinose solution induced higher ultrafiltered volume than the low-osmolality glucose-enriched fluid at 120 minutes of dwelling time. No significant differences were observed in effluent sodium and potassium concentration and protein dialysate-to-plasma (D/P) ratio. The D/P ratio of phosphate was higher in the low-osmolality raffinose-based fluid than in the low-osmolality glucose solution. The osmolality of the solutions was significantly decreased after a dwelling time of 120 minutes. We conclude that 4.5% raffinose is an effective osmotic agent. Total or partial replacement of glucose by raffinose for clinical peritoneal dialysis could be eventually considered after appropriate evaluation of its biocompatibility and general side effects.