A mixture of: 7,9,9-trimethyl-3,14-dioxa-4,13-dioxo-5,12-diazahexadecane-1,16-diylprop-2-enoate; 7,7,9-trimethyl-3,14-dioxa-4,13-dioxo-5,12-diazahexadecan-1,16-diylprop-2-enoate

Basic toxicokinetics

Administrative data

Endpoint:

basic toxicokinetics

Type of information:

other: theoretical approach

Adequacy of study:

key study

Reliability:

other: not applicable

Rationale for reliability incl. deficiencies:

other: Study is based on expert judgment.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2011

Report date:

2011

Materials and methods

Objective of study:

other: toxicokinetic assessment

Principles of method if other than guideline:

A theoretical approach of the toxicokinetic properties of the substance based on the available physico-chemical properties and toxicological data.

Test material

Test material information

Constituent 1

Reference substance name:

A mixture of: 7,9,9-trimethyl-3,14-dioxa-4,13-dioxo-5,12-diazahexadecane-1,16-diylprop-2-enoate; 7,7,9-trimethyl-3,14-dioxa-4,13-dioxo-5,12-diazahexadecan-1,16-diylprop-2-enoate

EC Number:

412-260-6

EC Name:

A mixture of: 7,9,9-trimethyl-3,14-dioxa-4,13-dioxo-5,12-diazahexadecane-1,16-diylprop-2-enoate; 7,7,9-trimethyl-3,14-dioxa-4,13-dioxo-5,12-diazahexadecan-1,16-diylprop-2-enoate

Cas Number:

52658-19-2

Molecular formula:

C21H34N2O8 (molecular formula of the two isomers constituting the substance)

IUPAC Name:

2-({[(2R)-2,4,4-trimethyl-6-({[2-(prop-2-enoyloxy)ethoxy]carbonyl}amino)hexyl]carbamoyl}oxy)ethyl prop-2-enoate; 2-({[(2S)-2,4,4-trimethyl-6-({[2-(prop-2-enoyloxy)ethoxy]carbonyl}amino)hexyl]carbamoyl}oxy)ethyl prop-2-enoate; 2-({[(3R)-3,5,5-trimethyl-6-({[2-(prop-2-enoyloxy)ethoxy]carbonyl}amino)hexyl]carbamoyl}oxy)ethyl prop-2-enoate; 2-({[(3S)-3,5,5-trimethyl-6-({[2-(prop-2-enoyloxy)ethoxy]carbonyl}amino)hexyl]carbamoyl}oxy)ethyl prop-2-enoate; 2-({[2,2,4-trimethyl-6-({[2-(prop-2-enoyloxy)ethoxy]carbonyl}amino)hexyl]carbamoyl}oxy)ethyl prop-2-enoate; 2-({[2,4,4-trimethyl-6-({[2-(prop-2-enoyloxy)ethoxy]carbonyl}amino)hexyl]carbamoyl}oxy)ethyl prop-2-enoate

Details on test material:

- Substance type: Very viscous clear yellowish liquid
- Physical state: liquid
- Analytical purity: >=95%

Applicant's summary and conclusion

Executive summary:

In general, a compound needs to be dissolved before it can be taken up from the gastro-intestinal tract after oral administration (1). Based on the moderate water solubility (224 mg/L) and the lipophilic character of the main compound (Log Pow 2.7), the test substance has the potential to be absorbed by passive diffusion. Further, the relatively low molecular weight (442.5) is favourable for absorption. However, ionization of test substance will possibly impair the uptake since compounds need to pass the lipid membranes in the gastrointestinal wall (1). Overall, absorption of the test substance from the gastro-intestinal tract is expected to be likely, which is also confirmed by the results from the repeated dose studies in which systemic toxicity was present. For risk assessment purposes the oral absorption of the test substance is set at 100%.

 

Once absorbed, distribution of the test substance throughout the body is expected based on its relatively low molecular weight and moderate water solubility. Based on its relatively lipophilic character, intracellular concentration is expected to be higher than extracellular concentration.

Absorbed test substance might undergo conjugation (2). The conjugates will either be excreted via the bile (high molecular weight compounds) or the urine (low molecular weight compounds).

 

The high boiling point (>250˚C) and low vapour pressure (0.7 Pa) indicate that it is not likely that the test substance will reach the nasopharyngeal region or subsequently the tracheobronchial or pulmonary region. If the test substance reaches the tracheobronchial region, absorption through aqueous pores will be limited, taking the molecular weight of > 200 into account. However, its moderate lipophilic character (log Pow 2.7) is favourable for crossing the alveolar and capillary membranes and the high water solubility of test substance (224 mg/L) is favourable for dissolution of the substance in the mucus lining of the respiratory tract. If the test substance is inhaled, significant absorption of the substance is to be expected. For risk assessment purposes the inhalation absorption of test substance is set at 100%.

 

The test substance being a liquid has the potential to partition from the stratum corneum into the epidermis, which is also enhanced by the moderate water solubility (224 mg/L). Further, the moderate lipophilic character of the major component (log Pow2.7) indicates that the transfer between the stratum corneum and the epidermis will be likely. Based on the molecular weight (442.5) and the log Pow, the criteria for 10% dermal absorption as given in the TGD (3) (MW > 500 and log Pow< -1 or > 4) are not met, and hence a dermal absorption of 100% is proposed for risk assessment purposes. The results of the toxicity studies do not provide reasons to deviate from this proposed dermal absorption factor.

 

Based on the present available data, no additional conclusions can be drawn on the metabolism and excretion of the test substance after dermal and inhalatory absorptio.

REFERENCES

 1.    Martinez, Amidon GL. Mechanistic approach to understanding the factors affecting drug absorption: a review of fundamentals. J Clin Pharmacol 2002; 42: 620-43.

2.    Guidance for the implementation of REACH. Guidance on information requirements and chemical safety assessment. Chapter R.7c: Endpoint specific guidance. European Chemical Agency, May 2008

3.    A. Parkinson. In: Casarett and Doull’s Toxicology, The basic science of poisons. Sixth edition. Ed. C.D. Klaassen. Chapter 6: Biotransformation of xenobiotics., McGraw-Hill, New York, 2001.