4.2.2-Toxicity
4.2.2.1-Oral absorption
L-Glutamic acid has a molecular weight of less than 500 g/mol and a log Kow of -4.99 which is in general a prerequisite for
for absorption.its structure L-asparagine possesses two pKa values therefore it will be present in its unionized form in
stomach (pH 2) as well as in the small intestine (pH 8) which is also favourable for absorption.
4.2.2-2-Respiratory absorption
L-Glutamic acid is a solid at room temperature and decomposes at 235°C together with a low vapor pressure of 2.26 E-005 Pa
substance evaporation and uptake by inhalation is unlikely. However, the uptake after direct inhalation of substance dust
particles and aerosols is possible because L-Glutamic Acid is marketed and used in a granular form,but considered very
unlikely because the median particle size was determined to be D50 = 251.2 µm which is above the critical size for particles
Nevertheless, after uptake L-Glutamic Acid it will be readily absorbed due to its physicochemical properties, its high water
solubility (22.1g/L) or its low log Kow and is therefore unlikely to be coughed or sneezed out of the body.
A deposition into lymphoid tissues is also rather unlikely.Because L-Glutamic Acid is produced and marketed in granular form
accidental exposure to dusts cannot be excluded.Thus, for precautionary reasons the estimated absorption of L-Glutamic Acid
via the respiratory tract is 100%.
4.2.2.3-Dermal
Due to its low molecular weight, its low log Kow and its high water solubility, L-Glutamic Acid may be dermally absorbed.
Based on the pKa values of which one is 2.02 and the other is 8.80 L-Glutamic Acid is supposed to be partially ionized, but due
to its small size (MW 132.12 g/mol) it is presumably absorbed. However, since L-Glutamic Acid is handled in its solid form,
it is not expected to be dermally absorbed.Thus because uptake of L-GlutamicAcid by dermal route is not expected but can also
not be excluded and because dermal absorption is not expected to exceed oral uptake a value of 50% absorption after dermal
exposure should be assumed
4.2.2-4-Distribution
As a small molecule a wide distribution can be expected. It was reported that the main occurrence of L-Glutamic acid was
detected in the wholecarcass, whereas only 14.3% were recovered in the gastro-intestinal tract and 7% of dietary administered
L-glutamic acid was found in the liver The amount of respired L-Glutamic Acid was measured in another study but with
remarkable varying results,between 14 and 36% of i.p. or s.c administered L-Glutamic Acid was respired as CO2
4.2.2-5-Metabolism
As a ubiquitous occurring molecule, L-Glutamic Acid in known to be readily metabolised by the intermediary metabolism.
As mentioned before,it is a substrate for the synthesis of L-Glutamic acid and therefore participates as a precursor in the
generation of neurotransmitter. It was shown that L-Glutamic Acid administered in a rat model of sepsis was able to improve
muscle wasting and reduce weight loss naturally occurring with the condition of sepsis . In another study it was reported that
endotoxin administration inhibited gluconeogenesis rising from L-Glutamic Acid as a source The results presented in this
study indicate that L-Glutamic Acid plays a pivotal role in intermediary metabolism and its inhibition may be deleterious.
4.2.2-6-Elimination
The major routes of excretion for substances from the systemic circulation are the urine and/or the faeces.L-Glutamic Acid
is rather incorporated into proteins than renally or biliary excreted.
4.2.2.7-Repeated Dose Toxicity
4.2.2.8-Genetic Toxicity
4.2.2.9-Carcinogenity
4.2.2.10-Toxicity to Reproduction
4.2.2.11-Ecological Toxicity