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Description of key information

Short description of key information on bioaccumulation potential result: 
The results of three studies indicate that DMT is rapidly and extensively absorbed following oral administration. DMT is almost completely metabolised to terephthalic acid (TPA) by ester hydrolysis, and is largely excreted in the urine. The results of the studies indicate little potential for bioaccumulation
Short description of key information on absorption rate:
Dermal absorption of approximately 11% of a single dose and 13% of a repeated dose is reported in a study in the rat in vivo.

Key value for chemical safety assessment

Bioaccumulation potential:
no bioaccumulation potential
Absorption rate - dermal (%):
13

Additional information

The results of three studies indicate that DMT is rapidly and extensively absorbed following oral administration. DMT is almost completely metabolised to terephthalic acid (TPA) by ester hydrolysis, and is largely excreted in the urine, causing acidification. The results of the studies indicate little potential for bioaccumulation.

Discussion on bioaccumulation potential result:

Moffit et al (1975) investigated the absorption, distribution, and excretion of radioalabelled dimethylterephthalate (DMT) following oral, intratracheal, dermal and ocular administration to rats and rabbits.The results of the study indicate the rapid absorption and excretion of DMT with no evidence of bioaccumulation in rats, following single or repeated oral or intratracheal administration. Following the dermal application of 80 mg DMT in the rat, absorption of approximately 11% of a single dose and 13% of a repeated dose is reported (based on excretion in the urine and faeces of rats within 10 days). Following application to the conjunctival sac of one eye of eight rabbits, excretion of approximately 33% of a single ocular dose of 50 mg DMT in the urine and faeces of rabbits within 10 days is reported. Results suggest that DMT is rapidly absorbed and excreted and that there is no evidence for bioaccumulation.

In an addtional study (Heck & Kluwe, 1980), young adult female F-344 rats (160-180 g) were fed a diet containing 1% and 2% dimethyl terephthalate. Fresh samples of rat urine were collected daily over a three week period. Analysis of the urine showed that treatment of rats with dimethyl terephthalate resulted specifically in urinary acidosis and hypercalciuria. The acidosis was probably caused by metabolism of dimethyl terephthalate to terephthalic acid, which was virtually complete in single dosed rats. Results indicated that acidosis was the cause of hypercalciuria and can develop during ingestion af any weak acid or of compounds such as DMT whose metabolism leads primarily to acid production.

In a third study (DuPont, 1958), groups of rats were fed diet containing either 5% terephthalic acid or an equivalent amount of its sodium salt or dimethyl ester for five days followed by five days of the control diet. Urine and faeces samples were collected and analysed. Results showed that DMT is almost completely absorbed and eliminated by the kidney. Only a trace of the ingested DMT that is absorbed is excreted unchanged in the urine, the rest is metabolised to its acid

Discussion on absorption rate:

The dermal absorption of DMT was investigated as part of the investigation of the absorption of DMT by various routes (Moffit et al, 1975). Following the dermal application of 80 mg DMT in the rat, absorption of approximately 11% of a single dose and 13% of a repeated dose is reported (based on excretion in the urine and faeces of rats within 10 days).