Hexadecyl methacrylate

Endpoint summary

Description of key information

Subacute study; oral (gavage); rat (Sprague Dawley SD), m/f (OECD guideline 422, Klimisch score: 1,GLP), no toxicity occurred up to the highest administered dose of 1000 mg/kg/day with the structural analogue dodecyl methacrylate: NOAEL = 1000 mg/kg bw/d (CIT, 2007).
With regard to the low repeated dose oral toxicity and the characteristics of skin penetration and metabolism in the skin, the repeated dose dermal toxicity can be considered as low. The inhalation route is not of relevance due to the very low vapour pressure of the substance. 

Key value for chemical safety assessment

Repeated dose toxicity: via oral route - systemic effects

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

NOAEL

1 000 mg/kg bw/day

Study duration:

subacute

Species:

rat

Quality of whole database:

There is no study available for hexadecyl methacrylate but for structural analogue substances dodecyl methacrylate and 2-ethylhexyl methacrylate.
In a well-conducted OECD combined repeated dose and reproductive/developmental toxicity screening test (OECD TG 422) by oral gavage in rats no toxicity occurred up to the highest administered dose of 1000 mg/kg/day. The NOAEL was determined to 1000 mg/kg/day. (CIT, 2007, relaible without restriction (Klimisch score: 1))
Supporting information: OECD guideline 408 90-day gavage study in Wistar rats with the C8 Ester 2-ethylhexyl methacrylate, including a recovery period of 28 days, signs of general systemic toxicity occurred in male as well as female rats at 360 mg/kg bw/day. NOAEL was 120 mg/kg bw/day in males and females. Relaible witout restriction (BASF, 2009, Klimisch score: 1, GLP)

Repeated dose toxicity: inhalation - systemic effects

Endpoint conclusion

Endpoint conclusion:

no study available

Repeated dose toxicity: inhalation - local effects

Endpoint conclusion

Endpoint conclusion:

no study available

Repeated dose toxicity: dermal - systemic effects

Endpoint conclusion

Endpoint conclusion:

no study available

Additional information

There is no study available for hexadecyl methacrylate but for structural analogue substances dodecyl methacrylate and 2-ethylhexyl methacrylate.

There is one relevant and adequate study available for dodecyl methacrylate on repeated dose toxicity (RL=1, guideline study according to OECD 422, GLP).

In a Combined Repeated Dose Toxicity Study with the Reproduction / Developmental Toxicity Screening Test according to OECD Guideline 422 (22 March 1996) dodecyl methacrylate was administered to 10 Sprague Dawley SD rats/sex/dose orally by gavage at dose levels of 0 (control), 100, 300 and 1000 mg/kg bw/d. The treatment schedule included 15 days before pairing, during pairing and post-mating periods until sacrifice for males (ca. 6 weeks in total) and females15 days before mating, during the mating period,during pregnancy and lactation, until day 5 post-partum inclusive (or until sacrifice, for un-mated females).

At 1000 mg/kg/day, hypersalivation was recorded in males and females, lower body weight gain was recorded in females during the GD 0-7 interval and increased plasma glucose concentrations were recorded in males. At 300 mg/kg/day, a few animals had hypersalivation. At 100 mg/kg/day, no treatment-related effects were detected. Hypersalivation was not considered to be a sign of toxicity to dodecyl methacrylate. There were neither substance-induced effects on the male and female reproductive performance, nor on the progeny of the parental rats at any dose-level. There were no treatment-related findings at histopathological examination. Based on the experimental conditions of this study, the No Observed Adverse Effect Level (NOAEL) for parental toxicity was considered to be 1000 mg/kg/day and the No Observed Effect Level (NOEL) for toxic effect on reproductive performance and on developmental toxicity was greater than or equal to 1000 mg/kg/day.

Supporting information: In an OECD guideline 408 90-day gavage study in Wistar rats with the C8 Ester 2-ethylhexyl methacrylate, including a recovery period of 28 days, signs of general systemic toxicity occurred in male as well as female rats at 360 mg/kg bw/day. The NOAEL was 120 mg/kg bw/day in males and females.

There are no data available for repeated dose exposure by the dermal or inhalation route. With regard to the low repeated dose oral toxicity and the characteristics of skin penetration and metabolism in the skin, the repeated dose dermal toxicity can be considered as low. The skin absorption study indicates that the total amount of the ester dodecyl methacrylate that was absorbed during the time of exposure was 0.7 % (rat epidermis) and 0.26 % (rat whole skin) over 24 hours, respectively. Thus, toxic effects via the dermal route are unlikely. The inhalation route is not of relevance due to the very low vapour pressure of the substance.

Taken as a whole there are sufficient data available for the long-chain alkyl methacrylate esters for assessment purposes so for the sake of animal welfare it is not proposed to conduct further repeated dose studies.

Justification for classification or non-classification

Based on the available data, hexadecyl methacrylate does not need to be classified for repeated dose toxicity according to the criteria given in regulation (EC) 1272/2008 CLP (EU-GHS) or the former European directive on classification and labelling 67/548/EEC.

Thus, no labelling is required.