The plasma clearance of indocyanine green in rats with acute renal failure: effect of dose and route of administration.

The pharmacokinetics of various doses (1-7.5 mg/kg i.v.) of indocyanine green (ICG) have been studied in control rats and rats with glycerol-induced acute renal failure (ARF). The pharmacokinetic changes seen at a dose of 1 mg/kg, after jugular vein administration, were significant decreases in uraemic rats in the rate of entry of ICG into the liver (k12) and in the rate of movement of dye from liver to plasma (k21). Greater and more numerous changes in pharmacokinetic parameters were recorded in experiments conducted using 4.0 and 7.5 mg/kg ICG. The results from these experiments showed that in addition to significant decreases in k12 and k21 there was a significant reduction in the rate constant for transfer of dye from liver to bile (k23). These changes were accompanied by a significant decrease in plasma clearance. In a separate series of experiments steps were taken to reduce the degree of uraemia produced by glycerol injection. The findings from these experiments showed no significant pharmacokinetic differences between control and mildly uraemic animals after administration of a dose of 7.5 mg/kg ICG. This suggests that the kinetic changes described above were a consequence of renal failure and not a direct hepato-toxic effect of glycerol.