Medical Evidence
Pharmacokinetics of Glucosamine in the
Dog and in Man I. Setnikar1, C. Giacchetti2, and
G. Zanolo3 From Rotta Research Laboratorium1, Monza (Italy) and
Istituto di Ricerche Biomediche "Antoine Marxer" S.p.A.2, Ivrea-Torino
(Italy)
Summary: The pharmacokinetics,
organ distribution. metabolism and excretion of glucosamine were
studied in the dog giving uniformly labelled 14C-glucosamine (sulfate),
i.v. or orally in single doses.
Immediately after i.v.administration the radioactivity in plasma
is due to glucosamine, and freely diffuses into organs and tissues.
This radioactivity disappears quickly from plasma (initial t1/2
= 13 min, terminal t1/2 = 118 min). After 30-60 min the radioactivity
in plasma is no longer due to glucosamine but is incorporated
into a- and B-globulins.. The protein-incorporated radioactivity
is found already 20-30 min after i.v. administration. reaches
a peak after 8 h and then slowly disappears, with a t1/2 = 2.9
days. Of the administered radioactivity. more than 34% is excreted
in the urine, mainly as glucosamine, and 1.7% is excreted in the
feces. Radioactivity is excreted also as 14C-CO2 in the expired
air. The radioactivity, after i.v. administration, diffuses rapidly
from blood into the body. Some organs show an active uptake of
radioactivity, e.g. the liver and the kidney. Other tissues, such
as the articular cartilage, also have an active uptake. In most
other organs the radioactivity found can be explained by passive
diffusion processes from plasma. After oral administration of
a single dose of 14C-glucosamine the radioactivity is quickly
and almost completely absorbed from the gastrointestinal tract.
The pattern of disappearance. metabolic transformation, tissue
distribution and excretion of the radioactivity are consistent
with those found after i.v. administration.
In man, unlabelled glucosamine sulfate (Dona™ 200-S) was
given i.v. and orally and glucosamine was measured in plasma and
urine with a glucosamine-specific ion-exchange chromatographic
method. The results show that the bioavailability, pharmacokinetics
and excretion pattern of glucosamine are consistent with those
found in the dog with radiolabelled glucosamine, and with those
reported in a previous study in the rat.
Source: Arzneim-Forsch/Drug
Res. 36 (1), Nr. 4 (1986)