Hexadecyl lactate

Hydrolysis

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

hydrolysis

Type of information:

experimental study

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Principles of method if other than guideline:

In general, the methodology was based on U. Tauber et al., Pharmacol. Skin, Volume 1, pp. 170-183.

GLP compliance:

no

Radiolabelling:

no

Analytical monitoring:

yes

Buffers:

sodium phosphate buffer

Details on test conditions:

Alkyl lactate was weighed (0.05-0.08 g) and dissolved in sodium phosphate buffer, pH 7.4, in 50 mL volumetric flasks. In the instance of the higher weight alkyl (S)-(S)-lactates, octyl, dodecyl, and octadecyl, they were weighed directly into the HPLC vial using a microbalance. A calculated amount of the dissolved alkyl lactate was pipetted into a 5 mL volumetric flask to which 1 mL of enzyme solution or buffer (as in the case of assessing chemical hydrolysis) was added. In the case of octyl, dodecyl, and octadecyl (S)-lactates, 0.8 mL of enzyme or buffer was added and then diluted with 3.2 mL of buffer for a total volume of 4 mL.

Preliminary study:

Not performed.

Test performance:

Not specified.

Transformation products:

yes

No.:

#1

No.:

#2

% Recovery:

> 65 - <= 100

pH:

7

Temp.:

35

Duration:

ca. 6 h

pH:

7

Temp.:

35 °C

DT50:

> 24 h

Type:

(pseudo-)first order (= half-life)

Based on the above study, short chain esters and in particular C8 esters hydrolyzed far more rapidly than large chain esters such as C16 and C18 esters. In fact, after 24 hour period, there was little to no hydrolysis observed for C16 and C18 esters.

Validity criteria fulfilled:

not applicable

Conclusions:

Dodecyl lactate hydrolysed significantly during a six hour exposure period, whereas longer chain alkyl lactates (C16, C18) did not significantly hydrolyse during a period of 24 hours.

Reference 2

Endpoint:

hydrolysis

Type of information:

read-across based on grouping of substances (category approach)

Adequacy of study:

weight of evidence

Reliability:

4 (not assignable)

Rationale for reliability incl. deficiencies:

other: Secondary source

Justification for type of information:

REPORTING FORMAT FOR THE ANALOGUE APPROACH
1. ANALOGUE APPROACH JUSTIFICATION
Since there is a significant relation between the analogues measured and the target substance, which only differs in chain length of the alcohol, read-across is here justified.

Principles of method if other than guideline:

Not applicable.

GLP compliance:

no

Preliminary study:

Not performed.

Test performance:

Not specified.

Transformation products:

not specified

Remarks on result:

other: The C12 -14 alcohols have no hydrolysable structural features and would be expected to be stable in water. Oxidation would not be expected under normal environmental conditions.

Conclusions:

The C12 -14 alcohols have no hydrolysable structural features and would be expected to be stable in water. Oxidation would not be expected under normal environmental conditions.

Description of key information

Large chain esters such as cetyl lactate and long chain alcohols like hexadecanol appear to be hydrolytically stable.

Additional information

Based on the reported study, short chain esters and in particular C8 esters hydrolyzed far more rapidly than large chain esters such as C16 and C18 esters. In fact, after 24 hour period, there was little to no hydrolysis observed for C16 and C18 esters.