Registration Dossier

Administrative data

Endpoint:
surface tension
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: see 'Remark'
Remarks:
Modern GLP study. Note that lactide hydrolyses in aqueous solution with a half life @ 20°C and pH = 7 of 1.45 h. Hydrolysis lowers the pH and thereby speeds up the hydrolysis rate. Therefore, hydrolysis rates will also increase at higher concentrations. As such, measuring the surface tension of lactide solutions is not particularly relevant, as the solution will have reverted to a solution of lactic acid in a couple of hours. As such, the determination of the surface tension of a solution of lactic acid is more relevant.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2008
Report Date:
2008

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to
Guideline:
OECD Guideline 115 (Surface Tension of Aqueous Solutions)
Deviations:
no
Qualifier:
according to
Guideline:
EU Method A.5 (Surface Tension)
Deviations:
no
GLP compliance:
not specified
Type of method:
OECD harmonised ring method

Test material

Reference
Name:
Unnamed
Type:
Constituent

Results and discussion

Surface tension
Surface tension:
70.7 mN/m
Temp.:
20 °C
Conc.:
1 g/L

Applicant's summary and conclusion

Conclusions:
A standardized test for the surface tension of lactic acid resulted in the determination that a 1g/L solution of lactic acid in water has a surface tension of 70.7 mN/m; at this surface tension, it can be concluded that lactic acid is not a surface active substance. Since a molecule of lactide will ultimately result in 2 molecules lactic acid
Executive summary:

A standardized test for the surface tension of lactic acid resulted in the determination that a 1g/L solution of lactic acid in water has a surface tension of 70.7 mN/m; at this surface tension, it can be concluded that lactic acid is not a surface active substance.