methylethylketone peroxide trimer

Endpoint summary

Link to relevant study record(s)

Reference

Endpoint:

basic toxicokinetics in vitro / ex vivo

Data waiving:

other justification

Justification for data waiving:

other:

Description of key information

There is no specific requirement to generate TK information in REACH. (R.7.12.1). There are no adequate studies that completely address toxicokinetics (i.e. absorption, metabolism, distribution and elimination).  Physical-chemical properties were used to estimate absorption via oral, dermal and inhalation exposure. 

Key value for chemical safety assessment

Bioaccumulation potential:

no bioaccumulation potential

Absorption rate - oral (%):

100

Absorption rate - dermal (%):

20

Absorption rate - inhalation (%):

100

Additional information

Toxicokinetic Summary

1,2,4,5,7,8-Hexoxonane, 3,6,9-triethyl-3,6,9-trimethyl- CAS# 24748-23-0 is a cyclic peroxy ketone.

 

MW	Water Solubility	Log P	Vapor Pressure	Surface Tension	Systemic Toxicity
264	13.1 mg/L (slightly soluble)	4.84	4.1 Pa (0.0041 KPa)	Log10 Koc 3.16	Yes 90-day oral

 

 

 

No studies are available on the toxicokinetics, metabolism and distribution of this substance. The pure peroxide is not commercially available. 

 

Oral Absorption

There is no information on the oral absorption of this peroxide. While the water solubility would not favor absorption, repeat dose studies indicate systemic effects (liver, kidney and blood).

In a hydrolysis study, OECD 111, under the physiologically relevant conditions of pH 1.2, 37.0 ± 0.5 °C, the mean half-life of the test item was determined to be 0.23 hours (14 minutes), with a rate constant of 8.41 x 10^-4s^-1.

Dermal Absorption

Per ECHA Guidance on information requirements and chemical safety assessment Chapter R.7c: Endpoint specific guidance for dermal absorption:

 

MW: <100 favors absorption; > 500 does not

WS: 1-100 mg/L absorption is low to moderate

Log P: 1-4 favors absorption, > 4 penetration is limited by rate of transfer between stratum corneum and epidermis

VP: vapors with < 100 Pa are likely to be well absorbed and the amount absorbed dermally may be morethan 10% of the amount that would be absorbed by inhalation.

 

Based on the above guidance and physical-chemical properties, dermal absorption of the registered substance is estimated to be ~20% of oral absorption.

 

Inhalation Absorption

Per ECHA Guidance on information requirements and chemical safety assessment Chapter R.7c: Endpoint specific guidance for inhalation absorption:

VP: substances with VPs > 24 KPa are highly volatile; < 0.5 KPA have low volatility

 

Log P: 1-4 favors absorption, > 4 favors micellular solubilization if poor WS (1 mg/L or less)

 

WS: low WS enhance penetration to lower respiratory tract.

 

Based on the above guidance and physical-chemical properties, it is difficult to estimate the absorption via inhalation exposure of the registered substance. Therefore due to lack of information, for route to route extrapolation, a worse case will be assumed i.e. absorption via inhalation is twice that of oral absorption (Guidance on information requirements and chemical safety assessment, Chapter R 8.4).