[No public or meaningful name is available]

Endpoint summary

Link to relevant study record(s)

Reference

Endpoint:

basic toxicokinetics, other

Type of information:

other: Assessment

Study period:

02 July 2021

Objective of study:

toxicokinetics

The substance is of Unknown or Variable composition, Complex reaction products or Biological materials (UVCB) with multiple constituents. The physical state of the substance is liquid. Four constituents of the substance are considered to be of primary interest; vapor pressures of these representative compounds range from 1.96E-7 to 1.40E-6 Pa at 25°C. These values provide evidence that potential inhalation of the substance due to volatilization is negligible.

 

The substance is essentially insoluble in water, with water solubility < 10.9 µg/mL at 25°C. The partition coefficient (Log Pow) of the material could not be determined by either the Organisation for Economic Co-operation and Development (OECD) Test Guideline (TG) 117 (HPLC Method) or OECD TG 107 (Shake Flask Method). The physicochemical property instead was calculated from the individual solubilities in n-octanol and water, and found to be 4.69, thus the substance is lipophilic. The typical molecular mass of the product is greater than 500 Daltons. When considered in light of the Lipinski Rule Oasis of the OECD Quantitative Structure–Activity Relationship (QSAR) Toolbox, the substance is considered as not bioavailable via the oral route. This is further supported by an acute oral gavage toxicity study in female rats that found no systemic effects up to 2000 mg/kg-bw, the highest dose tested. In a 28-day oral gavage repeat dose study, however, systemic effects including decreased hematocrit in female rats and decreased relative heart weight in male rats were seen in doses as low as 200 mg/kg-bw/d.

 

Clinical chemistry changes were noted in female rats at doses of 300 mg/kg-bw/d and higher in an OECD TG 422 study. These data suggest that the substance may be absorbed via the oral route. No information is available currently on possible degradation products produced in the gastrointestinal tract.

 

The extremely low water solubility, very high lipophilicity, and large molecular weight of the substance indicate that it is not expected to be absorbed via the dermal route. An acute dermal toxicity study in rats showed neither mortality nor systemic effects up to 2000 mg/kg, the highest dose tested.

 

So-called “PBT” characteristics (i.e., persistent, bioaccumulative, and toxic) generally are considered to determine whether a substance poses a significant concern to the environment. The substance was found to be biodegradable within 28 days, per OECD TG 301F, and readily biodegradable per the Chemical Substances Control Law of Japan. Due to the variable composition of the substance, its calculated soil adsorption coefficients (K_oc), which often are used as surrogates for bioaccumulation potential, range from < 18 to 6752. The HPLC method found a K_oc of 132 for the main peak of the substance, indicating high mobility in soil. There is, therefore, low potential for the substance to bioaccumulate in aquatic organisms. The substance showed low acute toxicity to algae (72-hour E_rC₅₀ of > 100 mg/L), daphnia (48-hour EC₅₀ of 56 mg/L), and fish (96-hour LC₅₀ of 42 mg/L) in OECD TG 289, 202, and 203 studies, respectively.

 

In conclusion, the available data show that inhalation of the substance is not a concern unless the substance were to be aerosolized intentionally into respirable droplets. Dermal absorption of the substance is unlikely. Oral bioavailability is low, as evidenced by both the acute and systemic in vivo toxicology data. Environmental concern regarding the substance is expected to be limited.

Conclusions:

In conclusion, the available data show that inhalation of the substance is not a concern unless the substance were to be aerosolized intentionally into respirable droplets. Dermal absorption of the substance is unlikely. Oral bioavailability is low, as evidenced by both the acute and systemic in vivo toxicology data. Environmental concern regarding the substance is expected to be limited.

Description of key information

The available data show that inhalation of the substance is not a concern unless the substance were to be aerosolized intentionally into respirable droplets. Dermal absorption of the substance is unlikely. Oral bioavailability is low, as evidenced by both the acute and systemic in vivo toxicology data. Environmental concern regarding the substance is expected to be limited.