Benzo[rst]phenanthro[10,1,2-cde]pentaphene-9,18-dione, reaction products with 1-chlorododecane

Endpoint summary

Key value for chemical safety assessment

Absorption rate - oral (%):

42

Absorption rate - dermal (%):

5

Absorption rate - inhalation (%):

22

Additional information

Due to the UVCB nature of the REACH substance, a set of representative structures of the main constituents were created and used to predict the potential ADME properties using GastroPlus.

The main constituents of this substance are an isoviolanthrone structure with several dodecane side chains attached to it and oligomers of dodecane. There is also residual lauryl chloride present as an impurity/unreacted starting material. The following structures were therefore generated for use in the prediction:

A - F: isoviolanthrone with 2 - 7 dodecane side chains

G - H: dodecane oligomers (2 and 3 dodecanes)

I: Lauryl chloride (present as an impurity)

For each substance the Fraction absorbed (and bioavailable) was determined for oral, dermal and inhalation routes. For constituents A - F the bioavailability via all routes decreased as the number of dodecane side chains increased. For all 6 structures the dermal bioavailability was predicted to be <0.1% (0.017 to 0.0006%); the oral bioavailability was highest for the structure with 2 side chains (approx 13%), but then rapidly dropped off as more chains were added (from 3.2 with 3 side chains, to 0.8 with 7 side chains); the inhalation bioavailability was predicted to be approximately double the oral availability (from 24% with 2 side chains to 2% with 7 side chains). However it should be noted that this substance is not volatile.

The dodecane oligomers were predicted to have a low dermal bioavailability (0.001 - 0.002%); oral bioavailability was approximately 90 -95% and inhalation bioavailability was approximately half the oral bioavailability (approx 45%).

Lauryl chloride was estimated to have high oral and dermal bioavailability (98 and 82% respectively) and somewhat lower inhalation bioavailability (59%).

The substance identity information demonstrated that the of the alkylated isoviolanthrene portion of the composition (approx 53%), typcially had 1 -7 dodecane groups, with the majority having 3 -5 dodecane groups. A smaller portion (3.5%) had greater than 5 alkyl groups. Based on this, it is predicted that the oral/dermal and inhalation absorption of this fraction would be approximately 1.5%, 0.0006% and 3% respectively.

For the alkyl protion of the composition (approx. 39%), the oral, dermal and inhalation absorption is predicted to be approximately 91%, 0.002% and 42.5% respectively.

Based on the different bioavailabilities of the constituents an average bioavailability for the REACH substance has been derived:

		bioavailability (%)
	% composition	Oral	Dermal	Inhalation
dye	55.00%	1.5	0.0006	3
alkyl	39%	91	0.002	42.5
Lauryl Ch	6%	98	82	59
	100.00%
		Proportional bioavailability (%)
		Oral	Dermal	Inhalation
dye		0.83	0.00033	1.65
alkyl		35.49	0.00078	16.58
Lauryl Ch		5.88	4.92	3.54
		Predicted bioavailability (%)
		Oral	Dermal	Inhalation
Total		42	5	22

However the majority of the absorbed fraction will be made up of the alkyl and lauryl chloride portion of the composition. The main alkylated isoviolanthrene constituent will be minimally absorbed