Supernatant from the crystallisation of L-threonine from the broth filtrate from the fermentative production of L-threonine

Endpoint summary

Description of key information

For L-threonine mother liquor itself there are no studies available. Therefore, data for the read-across substance Biofert Plusz are taken into further consideration.
In a sub-acute gavage range-finding study in male and female Wistar rats oral application of up to 1000 mg/kg bw/day (related to dry mass) for 14 days did not result in clinical signs, effects on body weight or food consumption, in relevant macroscopical changes at necropsy or effects on organ weights.
In a sub-chronic 90 d gavage GLP study according to OECD Guideline 408 with male and female Wistar rats, no effects of toxicological relevance were detected even at the high dose level of 1000 mg/kg bw/day (related to dry mass).

Key value for chemical safety assessment

Repeated dose toxicity: via oral route - systemic effects

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

NOAEL

1 000 mg/kg bw/day

Study duration:

subchronic

Species:

rat

Repeated dose toxicity: inhalation - systemic effects

Endpoint conclusion

Endpoint conclusion:

no study available

Quality of whole database:

In accordance with Section 8.6.2 in column 1&2 of REACH Annex VIII testing of sub-chronic toxicity via the inhalation route is not required. The read-across substance Biofert Plusz has very low vapour pressure (< 3*10E-5 hPa at 20°C) and based on the composition of Biofert Plusz, this vapour pressure applies likewise to L-threonine mother liquor. Therefore, the potential for the generation of inhalable forms is low and also the use of this substance will not result in aerosols, particles or droplets of an inhalable size, so that exposure to humans via the inhalation route is unlikely to occur. Furthermore the results of laboratory animal studies performed with Biofert Plusz show low acute dermal toxicity. In a 90 d oral repeated dose toxicity study with Biofert Plusz, the administration of up to 1000 mg/kg bw/d (related to dry mass) does not exacerbate systemic toxicity effects. The highest dose level tested corresponds to the limit dose recommended by the respective OECD guideline and is indicating both a low bioavailability and a low toxicity potential. This intrinsic property/toxicity potential can be extrapolated to repeated inhalation route administration.

Repeated dose toxicity: inhalation - local effects

Endpoint conclusion

Endpoint conclusion:

no study available

Repeated dose toxicity: dermal - systemic effects

Endpoint conclusion

Endpoint conclusion:

no study available

Quality of whole database:

In accordance with Section 8.6.2 in column 1&2 of REACH Annex VIII testing of sub-chronic toxicity via the dermal route is not required. The toxicological properties of L-threonine mother liquor and the read-across substance Biofert Plusz are indicating a low potential for a significant absorption via the oral and dermal route. In addition, in a 90 d oral repeated dose toxicity study with Biofert Plusz, the administration of up to 1000 mg/kg bw/d (related to dry mass) does not exacerbate systemic toxicity effects. The highest dose level tested corresponds to the limit dose recommended by the respective OECD guideline and is indicating both a low bioavailability and a low toxicity potential. This intrinsic property/toxicity potential can be extrapolated to repeated dermal route administration.

Repeated dose toxicity: dermal - local effects

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Additional information

In a 14 day gavage range-finding study with Biofert Plusz, dose levels of 100 - 1000 mg/kg bw/d (related to dry mass) were administered once daily to Wistar rats of both sexes (n=5 per sex and dose). Parameters investigated were clinical signs, body weights and food consumption, organ weights and macroscopic findings. None of these parameters was changed by the test item at any of the dose levels tested.

In a subsequent 90 d gavage GLP study according to OECD Guideline 408 with Biofert Plusz, male and female Wistar rats (n=10 per dose and sex) were dosed daily with the undiluted test substance at dose levels of 100 - 1000 mg/kg bw/d. The treatment caused no adverse effects at any of the applied doses.

In both studies the highest dose level tested corresponds to the limit dose recommended by the respective OECD guideline.