Objective: Hydroxyethyl starch (HES) is mainly eliminated via the kidneys.
Any information about extrarenal elimination obtained so far has been eithe
r incomplete or contradictory. The objective of this study was to quantify
the intestinal excretion of infused HES with a mean molecular weight of 200
,000 and a molar substitution of 0.5 (HES 200/0.5) and to compare the reapp
earance/recovery rate in urine and plasma.
Design: Prospective clinical study without control group.
Setting: The study was conducted at the Institute of Hypertension of the So
ciety of Clinical Pharmacology, Vienna, Austria, which is an establishment
for research in volunteers.
Participants: The results of six out of seven healthy male volunteers were
appropriate for analysis. One trial subject had to be excluded from the stu
dy because of severe protocol violation (mixing of stool and urine samples)
.
Interventions and methods: Each volunteer was administered 500 ml of 10 % H
ES 200/0.5 in a 0.9 % NaCl solution intravenously within 1 h. A gut lavage
with 61 of a polysaccharide free solution was continuously administered fro
m 3 h prior to until 2 h after the HES infusion to facilitate the collectio
n of the samples and to exclude any source of error at analysis. HES was qu
antified with the hexokinase method. Measurements and
Results: Right from the beginning of the infusion until 10 h after its comp
letion, the cumulative HES excretion with feces (principle parameter) and u
rine as well as selective plasma volume and HES plasma level were measured.
Six and 14 h after the infusion had been completed, the recovery rates of
HES in urine were about 30 % and 40 %, respectively, and in plasma about 23
% and 8 %, respectively. By contrast, not more than a kind of "background
noise amount" of MES (about 0.2 %) could be recovered in feces ( mean value
in % of the infused amount of the substance). Six and 14 h after the infus
ion had been completed, the total recovery rates of HES were 53 % and 49 %,
respectively.
Conclusion: In a physiologically unimpaired gut HES 200/0.5 is not, or only
to an infinitesimal extent, eliminated via The intestine. The question if
there is any alternative path to renal excretion for HES still remains to b
e answered. As the calculated reappearance/recovery rate of HES is only abo
ut 50 % of the administered dose, further investigations as to the final fa
te of HES appear necessary.