Butyl glycollate

Dermal absorption

Administrative data

Endpoint:

dermal absorption

Type of information:

(Q)SAR

Adequacy of study:

key study

Study period:

September 2010

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Expert judgement

Justification for type of information:

QSAR prediction: migrated from IUCLID 5.6

Data source

Reference

Reference Type:

other: Expert judgement

Title:

Unnamed

Year:

2010

Report date:

2010

Materials and methods

Test guideline

Qualifier:

no guideline available

Test material

Test material information

Constituent 1

Reference substance name:

Butyl glycollate

EC Number:

230-991-7

EC Name:

Butyl glycollate

Cas Number:

7397-62-8

Molecular formula:

C6H12O3

IUPAC Name:

butyl glycolate

Constituent 2

Reference substance name:

Polysolvan O

IUPAC Name:

Polysolvan O

Constituent 3

Reference substance name:

Glycolic acid-n-butyl ester

IUPAC Name:

Glycolic acid-n-butyl ester

Details on test material:

not applicable

Radiolabelling:

other: not applicable

Administration / exposure

Duration of exposure:

not applicable

Doses:

not applicable

No. of animals per group:

not applicable

Applicant's summary and conclusion

Conclusions:

The dermal absorption is suggested to amount to about 10% followed by wide-spread distribution and rapid elimination with regards to the log Pow of Butyl glycollate (Polysolvan O) of 0.38, the data on the hydrolysis products and compounds with comparable log Pows.

Executive summary:

Expert judgement on dermal absorption

No in vitro or in vivo studies are available on dermal absorption of Butyl glycollate (Polysolvan O).

With regards to dermal penetration and in case of missing data, the physical chemical properties and especially the log Pow provide valuable information on possible skin penetration behaviour. The log Pow of Butyl glycollate (Polysolvan O) is 0.38, which indicates a hydrophobic behaviour most probably due to the polar structure of the molecule. Compounds with a similar log Pow as e.g. 2-butoxyethanol (BE, butyl glycol, CAS 111-76-2, log Pow 0.81) are known to penetrate sufficiently through the skin. However, BE is chemically an ether, slightly more hydrophobic and therefore will penetrate much better than Butyl glycollate (Polysolvan O). Interestingly, its vapour pressure of 1.17 hPa is also very low (OECD, 1997). In addition, the log Pow of the breakdown product n-butyl alcohol (BA) is 0.88 and thus in the same order as Butyl glycollate (Polysolvan O), while the other breakdown product glycolic acid (GA) has a log Pow -1.11. BA is known to be readily absorbed through the skin. For GA a comprehensive data base on dermal penetration is available, which indicated that the penetration behaviour depends also on pH and composition of formulation. Generally, the observed skin penetration rates of GA ranged between about 2 – 30%, with higher penetration at lower pH. Finally, considering the slightly acidic physiological skin pH in the range of 5 -6 and with regards to the Log Pow, physical chemical properties and data on its principle metabolites, the dermal penetration of Butyl glycollate (Polysolvan O) is assumed as 10%. With regards to the activity of esterases in the skin as well as systemically in the body, the toxicokinetics and metabolic fate is considered as comparable as after oral intake.

Conclusions

The dermal absorption is suggested to amount to about 10% followed by wide-spread distribution and rapid elimination with regards to the log Pow of Butyl glycollate (Polysolvan O) of 0.38, the data on the hydrolysis products and compounds with comparable log Pows.