4-(1-methoxy-1-methylethyl)-1-methylcyclohexene

Endpoint summary

Key value for chemical safety assessment

Effects on fertility

Effect on fertility: via inhalation route

Endpoint conclusion:

no adverse effect observed

Study duration:

subchronic

Species:

rat

Quality of whole database:

For Orange Flower Ether the fertility assesment is based on the analogue Terpineol multi, which read across is documented and considered to be sufficiently reliable and adequate to cover the endpoint.

Additional information

Introduction

No reproductive toxicity studies are available for Orange Flower Ether (CAS #14576-08-0). Therefore the 90-day inhalation toxicity study available for Terpineol multi (CAS #8000-41-7) is used to assess the fertility for Orange Flower Ether.

Selection of available information on fertility from Terpineol-multi for Orange Flower Ether

For Terpineol-multi also an OECD TG 422 and a, 90-day dietary study on males is available. Because these studies are of a shorter duration or limited to one sex (males), respectively, the 90-day inhalation study is considered to be the key study for fertility.

Relevance of effects in the Terpineol-multi studies. In the 90-day inhalation study no adverse effects were see at ≥2230 mg/m3. In the oral gavage OECD TG 422 some sperm effects were seen at 750 mg/kg bw but not at 250 mg/kg bw, considered to be due to bolus dosing. This reasoning is supported with a 90 -day dietary study in males showing absence of effect at ca 800 mg/kg dw.

Conversion of inhalation data towards mg/kg bw data: When converting the NOAEC of the 90-day inhalation study to a mg/kg bw dose for the rat the oral and dermal NOAEL rat would become ≥300 mg/kg bw (2230 mg/m3*0.38m3/kg d (respiratory volume rat)*6h/24h (exposure time in the test versus 24h)*5d/7d exposure time in a week)*100/50% (inhalation absorption versus oral absorption).

Conclusion on fertility vial all routes: In view of the of the absence of effects in the inhalation study (and in the dietary study) and the fact that Terpineol-multi is tested at the maximum achievable dosages, the final conclusion is that there are 'no hazards'identified vial all routes during 90-days for fertility.

Further information: Information on fertility other than the 90-day inhalation and the oral gavage OECD TG 414 the REACH Dossier of Terpineol-multi can be explored.

The NOAEC in the study presented below is > 2230 mg/m3. This concentration is above the saturated vapour pressure (SVP) of Terpineol-multi and of Orange Flower Ether (411 and 685 mg/m3, respectively) and therefore no adverse fertility effects are anticipated at the limit dose (see for calculation of the SVP the acute toxicity Endpoint summary for inhalation).

The conversion from the NOAEC in the inhalation study towards a systemic value in mg/kg bw is300 mg/kg bw.

The developmental toxicity for Orange Flower Ether is assessed using the Terpineol-multi information on an oral gavage OECDTG 414 resulting in a NOAEL of ≥600 mg/kg bw. This value is considered a limit dose because at higher doses the metabolic pathway is overloaded as presented for Terpineol-multi in an OECD TG 422 test (see for further information this REACH dossier).

The summaries of the both the fertility and the developmental toxicity is presented below. Thereafter the read across justification is presented.

Terpineol-multi repeated dose toxicity summary

Introduction: In a repeated dose toxicity study conducted according to OECD Guideline 413 and in compliance with GLP, terpineol multiconstituent was administered by inhalation-aerosol to groups of Crl:CD(SD) rats (10 rats/sex/ group) by snout-only inhalation exposure at target exposure levels of 0.2, 0.6 and 2 mg/L for 6 hours per day, 5 days per week for 13 weeks. Control animals received air only. Recovery animals were similarly treated for 13 weeks followed by a 4 week off dose period. Control and high dose recovery groups were included (10/sex/group). During the study, clinical condition, body weight, food consumption, ophthalmoscopy, haematology (peripheral blood), blood chemistry,organ weight, macropathology and histopathology investigations were undertaken.

Results exposure: The achieved levels were 101, 95 and 112% of the target concentrations of 0.2, 0.6 and 2 mg/L, respectively (achieved concentrations 0.202, 0.572 and 2.23 mg/L).MMAD: <0.52, 0.7 and 1.6 µm for achieved concentrations of 0.202, 0.572 and 2.23 mg/L, respectively.GSD: 2.99 and 1.75 for achieved concentrations of 0.572 and 2.23 mg/L, respectively.MMAD showed a general increase with increasing aerosol concentration. The MMAD for the low dose groupcould not be calculated, as virtually all the measurable test material was captured on the final filter stage, and the value presented is based on the cut point of the penultimate impactor stage. The mid dose groupsparticle size distribution values showed a bi-modal distribution with an average of 49% of the captured droplet having a MMAD below 0.52 µm. The MMAD value for the high dose group was within the ideal range (1 to 3 µm), indicating that the aerosol was respirable to the rats. The MMADs for the low and mid dose groups were below the ideal range of 1 to 3 µm. However, since the delivered aerosol was a liquid, it is likely that those inhaled droplets with an aerodynamic diameter below 1 µm would still have impacted on airway surfaces and not been exhaled.

Results general toxicity: There were no treatment related deaths or effects on food consumption, blood chemistry, ophthalmoscopy, organ weights or macropathology findings.Group mean body weight gains were lower than control for males exposed to 0.202 mg/L and for both sexes exposed to 0.572 and 2.23 mg/L. In both sexes, no relationship between exposure concentration and body weight gain was observed but the decrease in mean body weight gain was statistically significant for males exposed to 2.23 mg/L. Body weights showed full recovery for animals previously exposed to 2.23 mg/L.Clinical pathology measurements following 13 weeks of exposure revealed statistically significantly lower group mean reticulocyte percentages and absolute counts for males exposed to 0.572 or 2.23 mg/L, compared to control (as low as 0.82X control). A similar effect was observed for females exposed to 2.23 mg/L (as low as 0.87X control) but this did not attain statistical significance. During Recovery Week 4, values for both sexes previously exposed to 2.23 mg/L were similar to controls. Histopathological changes related to treatment were observed in the nasal turbinates for the majority of animals given the test substance and nasal pharynx for a limited number of animals given 0.572 or 2.23 mg/L.In the nasal turbinates, minimal to slight hyperplasia of the mucous cells in the respiratory epithelium was present at all exposure levels and did not exhibit a clear dose response in terms of incidence or severity in males, although there were slightly higher incidences in females at 0.572 mg/L or 2.23 mg/L compared with females exposed to 0.202 mg/L. After 4 weeks of recovery, partial recovery was evident, in terms of the severity observed. After 13 weeks of exposures, these changes were generally not associated with an inflammatory cell infiltrate or cellular degeneration; such changes were observed in a minority of animals and were of minimal severity. After 4 weeks of recovery, degeneration and inflammation of the respiratory epithelium showed completed recovery. However, degeneration of the olfactory epithelium showed only partial recovery in terms of the incidence observed. In the nasal pharynx, minimal hyperplasia of the mucous cells was also observed but at a lower incident and severity and was only evident for animals exposed to 0.572 or 2.23 mg/L. Complete recovery from this effect was observed following the 4 week recovery period. The aforementioned changes were typically associated with chronic exposure to an irritant material and are not considered adverse at the incidence and severity seen.

Results fertility: No effects were observed on the organ weight of the reproductive organs. In addition, gross macroscopy and histopathology of the reproductive organs did not show any changes due to treatment.

Conclusion: Therefore, the No Observed Adverse Effect Concentration (NOAEC) for general toxicity and fertility was considered to be ≥2.23 mg/L (2230 mg/m3). This means that also for Orange Flower Ether the NOAEC for general toxicity and fertility is ≥2230 mg/m3. A correction factor for molecular weight differences between Orange Flower Ether and Terpineol-multi is not needed because the value of Terpineol-multi is conservative and the systemic exposure for both substances will be via Terpineol (multi).

Toxicity to reproduction of Orange Flower Ether (CAS #14576-08-0) using read across from substances Terpineol-multi (CAS #8000-41-7)

 

Introduction and hypothesis for the analogue approach

Orange Flower Ether is an ether attached to a cyclohexyl ring with one double bond with a methyl-group attached at the para-position. For this substance no data regarding fertility and developmental toxicity are available. In accordance with Article 13 of REACH, lacking information should be generated whenever possible by mean other than vertebrate animals test, i.e. applying alternative methods such as in vitro tests, QSARs, grouping and read-across. For assessing the toxicity to reproduction of Orange Flower Ether the analogue approach is selected because for one closely related analogue, Terpineol-multi fertility and developmental information is available which can be used for read across. In accordance with Column 2 of the REACH Annex VIII regulation on fertility and developmental toxicity the information of the OECD TG 422 does not have to be submitted when a 90-day repeated dose toxicity study and a developmental toxicity study is available. Therefore the latter information will be used to cover the endpoint.

Hypothesis: Orange Flower Ether has similar fertility and developmental toxicity compared to Terpineol-multi because Orange Flower Ether metabolises into Terpineol (multi being a multi-constituent)

Available information: For the e source chemical Terpineol-multi a 90-day inhalation study is available which will be used for the fertility assessment. For the developmental toxicity the key study is a prenatal developmental study (OECD TG 414). Both studies are well conducted and performed according to the GLP guidelines and therefore receive a reliability of 1. Also the results of an OECD TG 422 are available in the REACH dossier of Terpineol-multi.

Target chemical and source chemical(s)

Chemical structures of the target chemical and the source chemicals are shown in the data matrix, including physico-chemical properties and toxicological information, thought relevant for repeated dose of both substances.

Purity / Impurities

Orange Flower Ether is a mono-constituent and contains impurities with the functional group, the ether bond, is absent or at another spot in the structure. This is similar to Terpineol-multi in which the functional group, the alcohol, can be absent or at a different spot in the structure. These impurities and/or minor constituents are not affecting the reproductive toxicity profile.

Analogue approach justification

According to Annex XI 1.5 read across can be used to replace testing when the similarity can be based on a common backbone and a common functional group. When using read across the result derived should be applicable for C&L and/or risk assessment and it should be presented with adequate and reliable documentation.

In accordance with ECHA guidance (2015, RAAF) Terpineol-multi was selected from a group of 4-substituted cyclohexene/hexane type of substances of which Terpineol-multi contained the most recent OECD TG 413 repeated dose toxicity information from which the fertility information was retrieved. For this substance also a recent developmental toxicity study is available with which both reproductive endpoints can be fulfilled.

Structural similarities and differences:Fertility and Developmental toxicity are systemic endpoints. Orange Flower Ether is metabolized into Terpineol (multi) and therefore this Terpineol can be used for read across. In the case that some non-metabolised substance enters the system via the dermal or inhalation route it can be seen that structurally both substances are similar. The only difference is that the Orange Flower Ether contains a methyl ether whileTerpineol has an alcohol group at this position. These groups have similar low reactivity and are not anticipated to present differences in fertility and developmental toxicity.

Toxico-kinetic similarities and differences:Absorption:Orange Flower Ether and Terpineol-multi both have physico-chemical properties that present full oral absorption and significant dermal and inhalation absorption. Though Orange Flower Ether has lower water solubility and a higher log Kow the values are still in the range of high absorption. The difference in vapour pressure may not be real, the high measured vapour pressure of Terpineol-multi is somewhat out of the range of Alpha-Terpineol measured to be 6.5 Pa (REACH dossier: Cas no: 98-55-5 and EC no 206-680-6) and also out of the EpiSuite calculation of 2.6 Pa, which generally predicts the vapour pressures of this type of fragrances.

Metabolism: Orange Flower Ether metabolises into Terpineol (multi) by demethylation of the ether CH3 group, resulting in Alpha Terpineol.

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Toxico-dynamic aspect: Reactivity: For systemic toxicity (after metabolism) the starting substance will be Terpineol, which data will be used for the read across. The reactivity of both functional groups: the methyl ether and the alcohol are considered to be of limited reactivity and are not expected to be important for receptor binding being mainly of hydrocarbon nature.

Experimental data similarity and differences:Except acute toxicity there are no endpoints with which the repeated dose toxicity can be compared with.For systemic toxicity (after metabolism) the starting substance will be Terpineol (multi), which fertility and developmental toxicity data will be used for the read across.

In the 90-day inhalation study of Terpineol-multi no effects of fertility were found. In the OECD TG 414 no developmental toxicity was seen.

Though in an oral gavage OECD TG 422 study with Terpineol-multi (see REACH dossier) some testicular toxicity was seen at the high dose of 750 mg/kg bw only, this effect was not observed during dietary and inhalation dosing. Therefore it is anticipated that this effect is due to bolus dosing. Also in the Alpha Terpinyl Acetate dietary 140-day study no testicular effects were seen. In this OECD TG 422 no developmental toxicity was seen.

Uncertainty of the prediction:In view of Orange Flower Ether metabolizing into Terpineol the systemic exposure will be to Terpineol, its metabolites and conjugation products. This means that there is no remaining uncertainty: in view of similarities in structure, toxico-kinetic (absorption and metabolism) and anticipated toxico-dynamic profile (reactivity receptor binding) the read across is justified.In accordance with ECHA guidance (2015) the read across would receive a score of 5.

Data matrix

The relevant information on physico-chemical properties and toxicological characteristics are presented in the Data matrix.

Conclusions per endpoint for Hazard assessment and C&L.

For assessing the fertility of Orange Flower Ether the 90-day inhalation repeated dose toxicity study of the source substances Terpineol-multi is used. In view of the absence of fertility effects in this study no fertility effects for Orange Flower are anticipated.

For assessing the developmental toxicity of Orange Flower Ether the developmental toxicity information of Terpineol-multi will be used resulting in absence of adverse effects for this endpoint.

Final conclusion on hazard, C&L and risk characterisation

Based on the available data classification and labelling is not needed for reproductive and developmental toxicity according to CLP Regulation (EC) No. 1272/2008 and its updates. A DNEL does not have to be derived for these endpoints.

 

Data matrix for the read across to Orange Flower Etherfrom Terpineol

Common names	Orange Flower Ether	Terpineol (multi)
Chemical structures
CAS no	14576-08-0	8000-41-7
EC no	Registration in 2018 (238-620-0)	REACH registered in 2010: 232-268-1
Empirical formula	C11H20O	C10H18O
Smiles	O(C([C@@H]1CCC(=CC1)C)(C)C)C	C([C@@H]1CCC(C)=CC1)(C)(C)O
Physico-chemical data
Molecular weight	168.28	154.25
Physical state	Liquid	Liquid
Melting point, °C	-20	≥-35.9 ≤ -28.2
Boiling point, °C	222.2	≥ 214 ≤ 225
Vapour pressure, Pa	9.91 at 23°C	300 at 20°C
Water solubility, mg/L	85 at 23°C	2540 at 20°C
Log Kow	4.5 at 25°C	2.6 at 30°C
Human health endpoints
Acute oral LD50 in mg/kg bw	> 5000 (rat) (OECD TG 401)	>2000 (rat) (OECD TG 401)
Repeated dose Inhalation NOAEC	Read across from Terpineol-multi	2230 mg/m3 air (OECD TG 413)
Reproductive toxicity
Fertility NOAE(C)L	Read across from Terpineol -multi	2230 mg/m3 (OECD TG 413)
Developmental toxicity	Read across from Terpineol-multi	> 600 mg/kg bw/day (OECD TG 414)

 

Effects on developmental toxicity

Description of key information

Orange Flower Ether (OECDTG 414 via read across from Terpineol-multi): NOAEL =>600 mg/kg bw

Link to relevant study records

Reference

Endpoint:

developmental toxicity

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: the information is retrieved based on read across

Justification for type of information:

Orange Flower ether, using read across from Terpineol-multi, is not developmental toxic and a NOAEL of >=600 mg/kg bw is derived.
The read across documentation is copied into the endpoint summaryand is attached in the present study record.

Reason / purpose for cross-reference:

read-across source

Key result

Remarks on result:

not determinable due to absence of adverse toxic effects

Key result

Abnormalities:

effects observed, non-treatment-related

Key result

Remarks on result:

not determinable due to absence of adverse toxic effects

Key result

Abnormalities:

effects observed, non-treatment-related

Key result

Developmental effects observed:

no

Effect on developmental toxicity: via oral route

Endpoint conclusion:

no adverse effect observed

Species:

rat

Quality of whole database:

For Orange Flower Ether the developmental toxicity assesment is based on the analogue Terpineol multi, which read across is documented and considered to be sufficiently reliable and adequate to cover the endpoint.

Additional information

Introduction:

No developmental toxicity studies are available for Orange Flower Ether (CAS #14576-08-0). Therefore a developmental toxicity study (OECD TG 414) available for a structural analogue, Terpineol multi (CAS#8000-41-7), is used to assess the developmental toxicity for Orange Flower Ether. The NOAEL in the Terpineol-multi study is =>600 mg/kg bw.

Selection of information from Terpineol-multi.

For Terpineol-multi an OECD TG 422 and an OECD TG 414 is available. The OECD TG 414 replaces the informtion on developmental toxicity screening study and therefore the OECD TG 414 study is selected for Orange Flower Ether. In the OECD TG 422 screening study no adverse effects were seen on developmental toxicity >=750 mg/kg bw, supporting the results of the OECD TG 414 (For further information see the REACH dossier on Terpineol-multi.

The application of the Terpineol-multi information for Orange Flower Ether:

A conversion for molecular weight is not considered necessary because the difference is minimal and the value of Terpineol-multi is conservative. The 600 mg/kg bw is considered to be the maximum achievable dose as bolus dosing may occur.

Terpineol-multi developmental toxicity summary

In a GLP-compliant prenatal developmental toxicity study performed according to OECD guideline 414, the test substance diluted in corn oil was administered by gavage to groups of mated female Sprague-Dawley rats (20 mated females/dose) at the dose levels of 0, 60, 200, 600 mg /kg bw/ day from Days 6 to 19 after mating. Animals were inspected visually at least twice daily for evidence of ill-health or reaction to treatment. Detailed observations were recorded daily at the following times in relation to dose administration. A detailed physical examination was performed on each animal on Days 0, 5, 12, 18 and 20 after mating to monitor general health. The weight of each adult was recorded on Days 0, 3 and and then daily from Days 6 to 20 after mating. The weight of food supplied to each adult, that remaining and an estimate of any spilled was recorded for the periods Days 0-2, 3-5, 6-9, 10-13, 14-17 and 18-19 inclusive after mating.On Day 20 post-coitum, the dams were sacrificed and subjected to macroscopic examination. The gravid uterine weight, number of implantations, live and dead fetuses, early and late resorptions and corpora lutea were recorded. Gross evaluation of the placenta was also performed.Fetuses were sexed, weighed and examined for external, soft tissue and skeletal malformations.With the exception of one female in the 200 mg/kg bw/day group (No. 52) which had a total litter resorption, all females were found to be pregnant with live young at scheduled termination on Day 20 of gestation. No mortality was observed.At scheduled termination on Day 20 of gestation, the adjusted mean liver weight of females receiving 600 mg/kg bw/day was significantly higher than Control (1.10X Control). There were no treatment-related macroscopic abnormalities detected. No relevant clinical signs or signs of reaction to treatment were noted in treated females. Females receiving 60 or 200 mg/kg bw/day showed no treatment-related changes in clinical condition, body weight performance, food intake, liver weight or macropathology.There was no effect of maternal treatment with the test substance at any dose level investigated on litter data. Sex ratio, as assessed by the percentage of males per litter, was generally comparable in all groups and in line with expectations. Embryo-fetal growth was slightly reduced by maternal treatment at 600 mg/kg bw/day. It was considered that there was no adverse effect of maternal treatment on embryo-fetal development; the incidence of major and minor abnormalities and skeletal variants showed no relationship to maternal treatment with the test substance. In the 600 mg/kg bw/day group there was a slightly higher incidence of incompletely ossified or unossified 5th and/or 6th sternebrae compared to concurrent control and the Historical Control Data range. It was considered that this minor finding did not constitute an adverse effect on development. On the basis of the results obtained in this study, the dosage of 600 mg/kg bw/day was considered to be the NOAEL (No Observed Adverse Effect Level) for maternal and developmental toxicity. This means that also for Orange Flower Ether the NOAEL is >=600 mg/kg bw. A correction factor for molecular weight differences between Orange Flower Ether and Terpineol-multi is not needed because the value of Terpineol-multi is conservative and the systemic exposure for both substances will be via Terpineol (multi).

The read across documentation is added in the fertility section.

Justification for classification or non-classification

Based on the available information classification for reproductive and/or developmental toxicity is not warranted according to EU Classification, Labelling and Packaging of Substances and Mixtures (CLP) Regulation (EC) No. 1272/2008 and it updates.