(hydroxyethyl)urea

Endpoint summary

Description of key information

We have no specific data on the absorption, distribution, metabolism and excretion of Hydroxyethyl urea CAS No 1320-51-0.    We do have data from a series of predictive tools.

Key value for chemical safety assessment

Bioaccumulation potential:

low bioaccumulation potential

Absorption rate - oral (%):

50

Absorption rate - dermal (%):

50

Absorption rate - inhalation (%):

100

Additional information

We have no specific data on the absorption, distribution, metabolism and excretion of Hydroxyethyl urea CAS No 1320-51-0.   

Molecular chemical profile and estimated properties: There is an alternative CAS No 2078-71-9 and structure Urea, (2-hydroxyethyl) - model data for both is presented below.

Urea, (2-hydroxyethyl)- urea, (hydroxyethyl)- CAS 2078-71-9 1320-51-0 Physical state  solid  solid SMILES C(N)(=O)NCCO C(N)(=O)NC(C)O Molecular formula C3H8N2O2 C3H8N2O2 Molecular weight 104.1078 104.1078 Solubility:    avgLogS                          (g/L) 0.0 103 g/L -0.14 75 g/L Solubility (meas)    69.9 -74.9% Density    1350 pKa:   Neutral at all pH between 1 and 12 (starts to become anionic above) Neutral at all pH between 1 and 11 (starts to become anionic above) logPow(ALOGPS 2.1)        (KOWWIN v1.67) -1.64 (±0.28) -2.0631 -1.41 (±0.37) -2.1366 logPow (meas)    ca. -1.8 logD (Chemaxon) Not applicable Not applicable Mp (EPIWIN) 68.03 57.36 bp (EPIWIN) 266.46 250.68 Vp (EPIWIN) 0.0595 Pa 0.203 Pa Mp (meas)   82°C at 101.325 Pa bp (meas)   205°C at 101.325 Pa Vp (meas)   0.0015 Pa at 20°C Reactivity SN1: Nitrenium and/or carbenium forming SN1: Nitrenium and/or carbenium forming HOMO LUMO (difference: GAP) -10.4(-10.7;-10.2) eV 1.45(1.22;1.65) eV 11.85 eV -10.2(-10.3;-10.1) eV 1.46(1.15;1.73) eV 11.66 eV Dermal penetration coefficient Kp (est) 3.32e-005 cm/hr (0.0000332) 4.72e-005 cm/hr (0.0000472) Max. dermal absorption 0.0112 mg/cm²/hr 0.00927 mg/cm²/hr Human Intestinal absorption (HIA) 78% 77.2%

Absorption

Hydroxyethyl urea would be expected to be rapidly absorbed from the gastrointestinal tract; the modelling (Epiwin) information predicts ca. 77%.   It would be assumed to be readily absorbed in the lungs, although this is highly unlikely route of exposure.  It is also expected to be absorbed through the skin, the Epiwin model data below predicts 78.3% can reach the viable epidermis and therefore be available for absorption. See the attached file for the diagram.

Metabolism

DEREK and the OECD tool box are not able to predict the metabolites of hydroxyethyl urea. This substance is readily biodegradable; therefore it would be expected to be rapidly metabolized in the body. This might be expected to results in CO₂, water and urea.

Excretion

The urine would be expected to be the main route of excretion for the urea and water with the CO₂being exhaled.

References:

Molecular formula, molecular weight, pKa and logD were all calculated using ChemAxon MarvinSketch (v.5.4.0.1).

Melting point, boiling point, vapour pressure and logPow were estimated by EPI Suite (v4.1).

Solubility and logPow are estimated using ALOGPS 2.1 (VCCLAB, Virtual Computational Chemistry Laboratory,http://www.vcclab.org, 2005)

Reactivity: QSAR Toolbox v.3.0: profiling: DNA binding (OASIS v1.1; OECD); Protein binding (OASIS v1.1; OECD)

HOMO/LUMO Energy, [eV], and the quantum-chemical descriptor (the energy of the highest occupied resp. lowest unoccupied molecular orbital), are calculated in OASIS software, based on MOPAC 7.

(a large difference between HOMO and LUMO energies implies high stability and thus low reactivity)

Absorption properties:

- dermal: EpiSuite v. 4.1; intestinal (water:0.0005 cm/hr): (Pow based on ALOGPS 2.1)

- HIA: QSAR toolbox (version 3.1) (Human Intestinal Absorption)

Max. dermal absorption: IH Skin Perm v1.03 from AIHA (applying estimated data; density assumed 1)

EpiWin does not know CAS number 2078-71-9, and for CAS 1320-51-0 provides the structure with the terminal hydroxyl. Results for EpiWin in the table above are based on the structures.