2-Propenamide, 3-(1,3-benzodioxol-5-yl)-N,N-diphenyl-, (2E)-

Basic toxicokinetics

Administrative data

Endpoint:

basic toxicokinetics, other

Remarks:

Expert statement

Type of information:

other: Expert statement

Adequacy of study:

weight of evidence

Study period:

2022

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Expert statement

Data source

Reference

Reference Type:

other: Expert statement

Title:

Unnamed

Year:

2022

Report date:

2022

Materials and methods

Test material

Test material information

Constituent 1

Reference substance name:

(2E)-3-(2H-1,3-benzodioxol-5-yl)-N,N-diphenylprop-2-enamide

Cas Number:

1309389-73-8

Molecular formula:

C22H17NO3

IUPAC Name:

(2E)-3-(2H-1,3-benzodioxol-5-yl)-N,N-diphenylprop-2-enamide

Applicant's summary and conclusion

Conclusions:

Based on physicochemical characteristics, absorption of (E)-3-(1,3-benzodioxol-5-yl)-N,N-diphenyl-prop-2-enamide by the oral, inhalation or dermal route is expected to be low. This assumption is supported by the results of the acute, subacute and subchronic toxicity studies where no adverse effects were observed. The substance shows no strong bioaccumulation potential as the log Pow is below 4. If absorbed into the body, (E)-3-(1,3-benzodioxol-5-yl)-N,N-diphenyl-prop-2-enamide is most likely distributed into the interior part of cells due to its lipophilic properties (log Pow = 3.4) and in turn, the intracellular concentration may be higher than extracellular concentration, particularly in adipose tissues. No conclusions can be drawn about the metabolic transformation of the substance. On the basis of the molecular substance characteristics, excretion via bile is favoured.

Executive summary:

(E)-3-(1,3-benzodioxol-5-yl)-N,N-diphenyl-prop-2-enamide is an organic, mono-constituent substance. It is a light yellow powder at room temperature with a molecular weight of approx. 343.4 g/moL. The substance is poorly soluble in water (0.124 mg/L at 20 °C). The log Pow was determined to be 3.4. The test substance has a very low vapour pressure of 3.8 x 10^-11 Pa at 20 °C (extrapolated).

 

Absorption

According to the ECHA Guidance on Information Requirements and Chemical Safety Assessment, Chapter R.7c (Endpoint specific guidance), oral absorption is favoured for molecules with molecular weights of less than 500 g/moL. (E)-3-(1,3-benzodioxol-5-yl)-N,N-diphenyl-prop-2-enamide meets this criterion with a molecular weight of approx. 343.4 g/moL. Furthermore, its moderate log Pow of 3.4 might favour absorption by passive diffusion. However, the substance is not assumed to readily dissolve in gastrointestinal fluid due to its poor water solubility of 0.124 mg/L which might limit the rate at which the substance partitions out of the gastrointestinal fluid. As the molecular weight is greater than 200 g/mol, passage through aqueous pores or transport through the epithelial barrier by the bulk passage of water is unlikely. The median particle size was measured to be 27.5 µm which does not favour uptake by pinocytosis. Taken together, the physiochemical properties indicate that (E)-3-(1,3-benzodioxol-5-yl)-N,N-diphenyl-prop-2-enamide becomes poorly bioavailable following the oral route. This assumption is confirmed by the results of the acute oral toxicity study and repeated dose toxicity studies, where no systemic effects occurred up to the highest doses tested (2000 mg/kg bw in the acute study and 1443/1381 (males/females) or 489.5/492.2 (males/females) mg/kg bw/day in the 14-day range-finding study and the main subchronic feeding study, respectively).

Due to the very low volatility (vapour pressure of 3.8 x 10^-11 Pa at 20 °C (extrapolated)) and the boiling point above the decomposition temperature of 330 °C of (E)-3-(1,3-benzodioxol-5-yl)-N,N-diphenyl-prop-2-enamide, it is unlikely that the substance will be available as a vapour. Particles have the potential to be inhaled as the measured median particle size was 27.5 µm. Particles might also reach the thoracic region but the alveolar region of the respiratory tract can only be reached by a size fraction of smaller than 15 µm. Hydrophilic substances are likely to be retained within the mucus and thus, because of the poor water solubility of the substance, penetration to the lower respiratory tract might be enhanced, especially for smaller particle fractions. The moderate log Pow of 3.4 might favour absorption directly across the respiratory tract epithelium by passive diffusion, however, the low water solubility might limit the rate at which the substance partitions through the lung epithelium. No signs of systemic toxicity were present in the oral toxicity studies and thus, the absorption by inhalation might also be reduced.

(E)-3-(1,3-benzodioxol-5-yl)-N,N-diphenyl-prop-2-enamide is a non-volatile dry particulate solid with a molecular weight of approx. 343.4 g/moL, a logPow of approx. 3.4 and poor water solubility (0.124 mg/L). As dry particulates have to dissolve into the surface moisture of the skin before uptake can begin and the water solubility of the substance is low, substantial dermal absorption is unlikely. Furthermore, no effects were observed in skin irritation and skin sensitization tests. Thus, dermal absorption may not be the preferential route of entry into the body.

 

Distribution

As shown above, the physicochemical properties of (E)-3-(1,3-benzodioxol-5-yl)-N,N-diphenyl-prop-2-enamide suggest that oral, inhalation and dermal absorption of the substance is limited. No systemic absorption and distribution within the body leading to systemic toxic effects could be observed in acute and repeated-dose toxicity studies. If absorbed into the body, (E)-3-(1,3-benzodioxol-5-yl)-N,N-diphenyl-prop-2-enamide is most likely relatively widely distributed due to its molecular weight and may enter into the interior part of cells due to its lipophilic properties (log Pow 3.4) and in turn, the intracellular concentration may be higher than extracellular concentration particularly in adipose tissues.

The log Pow of (E)-3-(1,3-benzodioxol-5-yl)-N,N-diphenyl-prop-2-enamide indicates only a weak potential bioaccumulation potential as it is not above 4.

 

Metabolism

There is no direct experimental data to characterize the metabolism of the test substance. Instead, the anticipated metabolism is derived from expert judgement and reapplication of metabolic properties of related substances.

The genotoxicity studies indicated no remarkable differences with regard to genotoxicity and cytotoxicity with or without metabolic activation. Thus, no conclusions on metabolic activation or detoxification of the substance by liver enzymes can be drawn. No effects on metabolizing organs like the liver and kidney were observed in vivo, thus no conclusions can be drawn on whether the substance is principally able to reach the metabolic capacities of those organs.

 

Excretion

The physicochemical properties of the substance favour excretion via bile (molecular weight above 300 g/mol and low water solubility).