TRIETHYL CITRATE*
Explanation
This compound was reviewed at the 23rd and 25th Meeting of the
Joint FAO/WHO Expert Committee on Food Additives. (Annex 1, Ref. 50,
56) A temporary acceptable daily intake for man (ADI) of 0-10 mg/kg
b.w. was established. A toxicological monograph was published in 1980.
(Annex 1, Ref. 51.)
Since the previous evaluation, additional data have become
available and are summarized and discussed in the following monograph
addendum.
BIOLOGICAL DATA
Metabolism
Samples of freshly collected rat or human serum were spiked with
triethyl citrate and the disappearance of the triethyl citrate
measured over a 4 hr period. Triethyl citrate was rapidly hydrolysed
by rat serum (15 min.), but occurred at a much slower rate in human
serum and was not complete at the end of the 4 hr test period (Figdor
& Ballinger, 1981).
Rat-, mouse- and human-liver homogenates as well as serum enzymes
hydrolyse triethyl citrate to 1 mol citric acid and 3 mol ethanol/mol
ester (Burns & Werners, 1962).
Comments
Although it seems unlikely that unchanged triethyl citrate would
be absorbed, in vitro studies are available to show that both the
liver and blood serum have enzyme systems capable of hydrolysing the
ester.
EVALUATION
Level causing no toxicological effect
Rat: 4% in the diet (40,000 ppm) equivalent to 2 g/kg body
weight.
Estimate of an acceptable daily intake in man
0 - 20 mg/kg bw.
* Monograph addendum
REFERENCES
BRUNS, F.H. & WERNERS, H.P. (1962) Zum Stoffwechsel von Triathylcitrat
und Acetyltriathylcitrat. Klin. Wschr., 40: 1169.
FIGDOR, S.K. & BALLINGER, W.E. (1981) Triethyl Citrate Disappearance
from Rat and Human Serum. Unpublished report from Pfizer Central
Laboratory, Groton, Conn., USA. Submitted to the WHO.