Retention and distribution of polygeline (Haemaccel) in the rat

The plasma substitute polygeline (Haemaccel registered) contains a large fraction of molecules sufficiently small to cross the capillary and glomerular membranes. Plasma volume expansion, tissue extravasation and renal elimination of this artificial colloid were quantified using 125I-labelled polygeline molecules. In pentobarbital anaesthetized rats, either 10 ml 3.5% polygeline (n = 8) or 10 ml 0.9% saline (n = 8) was infused intravenously over 60 min. The plasma volume was assessed by the 3 min distribution volume for I-albumin and the plasma volume changes over time were calculated from erythrocyte volume fractions. The plasma volume increased by 4.6 (2.0) ml (mean (SD)) at the end of the Haemaccel infusion compared with 2.1 (1.8) ml after the saline infusion (P = 0.02). One hour later the increase was 2.4 (1.5) and 1.6 (1.0) ml respectively, not significantly different (P = 0.20). Extravasation of labelled polygeline was greatest in the kidney, possibly due to cellular uptake. Skin and skeletal muscle contained 4-5 times more polygeline than could be attributed to intravascular radioactivity, but still uptake in these tissues did not reach one percent of the amount injected. Following a 60 min infusion and a 60 min interval, 23 (4)% of the polygeline was recovered intravascularly, 43 (9)% had been excreted in urine, leaving 33% to other compartments. Thus, more polygeline was distributed to the interstitium than remained in the circulation. This calls for further investigations into the handling and effect of polygeline in this extravascular compartment.