Pyrimido[5,4-g]pteridine-2,4,6,8-tetramine, 4-methylbenzenesulfonate, base-hydrolyzed

Endpoint summary

Description of key information

Short description of key information on bioaccumulation potential result: 
Based on the physico-chemical properties and the absence of systemic toxicity in acute and repeated-dose studies, absorption of the study is unlikely.

Key value for chemical safety assessment

Bioaccumulation potential:

no bioaccumulation potential

Additional information

There were no studies available in which the toxicokinetic properties of the substance were investigated.

 

The substance is a yellowish powder, which is poorly soluble in water and has a low measured vapour pressure of 0.42 Pa at 20°C (see chapter „vapour pressure“). The calculated log Po/w is -0.74 at 20 °C.

Experimental studies on solubility properties of the main components of the substance were performed

(Brendle, E. Solubility measurements under specific defined conditions, Reference TKP 50052; Ciba Specialty Chemicals Inc., R&P Analytics PA, CH- 4002 Basel: September 2007)

. The solubility in n-octanol was determined to be below the detection limit of 10 μg/L and 50 μg/L for any of the main components and the trihydroxy minor component, respectively.. The solubility of the main components in phosphate buffer pH 7 is in

the range of 0.2 mg/L and – due to the protonation of the amino group – increases to 20 mg/L in 3% acetic acid. Considering this, the n-octaonol/water partition coefficient is expected to be less than zero, which is in line with the calculated value of -0.74 for the main component.

No indication of a substance specific systemic toxicity can be found in acute toxicity studies in rats with oral and dermal application (see chapter „acute toxicity“) as well as in a subacute toxicity study and reproductive toxicity screening study in rats with oral application (see chapter „repeated dose toxicity“ and "reproductive toxcity"). The observation of green faeces in the acute oral study is assessed as indication of intestinal passage of the pigment. The poor water solubility makes it unlikely that the compound will be absorbed to a high extent from the gastro-intestinal tract and the epidermis (ECHA guidance document 7c, 2008).

Uptake vapour is considered as not relevant due to the low vapour pressure.

Based on the poor solubility in water and the even poorer solubility in octanol, absorption of the substance is unlikely. This is confirmed by the absence of systemic toxicity in any of the available acute or repeated dose studies.

The substance is considered to be not absorbed, and to have no potential for bioaccumulation.