Registration Dossier

Hazard assessment conclusion:

DNEL (Derived No Effect Level)

Value:

44.1 mg/m³

Most sensitive endpoint:

repeated dose toxicity

Route of original study:

Oral

Overall assessment factor (AF):

6

Modified dose descriptor starting point:

NOAEC

Value:

264.5 mg/m³

Hazard assessment conclusion:

no hazard identified

Hazard assessment conclusion:

no hazard identified

Hazard assessment conclusion:

no hazard identified

Hazard assessment conclusion:

DNEL (Derived No Effect Level)

Value:

41.7 mg/kg bw/day

Most sensitive endpoint:

repeated dose toxicity

Route of original study:

Dermal

Overall assessment factor (AF):

24

Modified dose descriptor starting point:

NOAEL

Value:

1 000 mg/kg bw/day

Hazard assessment conclusion:

no hazard identified

Hazard assessment conclusion:

no hazard identified

Hazard assessment conclusion:

no hazard identified

Hazard assessment conclusion:

medium hazard (no threshold derived)

Available data:

In order to address the endpoint of sub-chronic toxicity of Tetrahydro-4-methyl-2-(2-methylpropyl)-2H-pyran-4-ol (Pyranol, CAS 63500-71-0) a 90-day repeated dose study in rats, dermal route (according to OECD 411) was performed (BASF SE 2014, 82R0639/09R137). Pyranol was administered 5 days per week to male and female Wistar rats dermally at dose levels of 0, 100, 300 and 1000 mg/kg bw/day over a period of 90 days. Each test group consisted of 10 animals per sex. Some male and female animals showed slight erythema, erosion and scales. These finding are attributed to the irritating properties of the test substance. No other test substance-related effects concerning clinical signs, body weight food consumption, water consumption, haematology, clinical chemistry, urinalysis, neurobehaviour, organ weights and histopathology were observed. Therefore, the NOEAL for repeated dose toxicity of this study was set to 1000 mg/kg bw/day.

In addition, a subacute (28 day) oral toxicity study (equivalent to OECD TG 407, GLP, Toxicol Laboratories 1989, FCH/2/88) with Pyranol is available. Three groups of 10 male and 10 female SD-rats received a suspension of Pyranol in 1% aqueous hydroxypropylmethylcellulose by gavage at dose levels of 25, 125 or 625 mg/kg bw/day whilst the control group received 1% aqueous hydroxypropylmethylcellulose alone. Administration of Pyranol by gavage at a dose level of 625 mg/kg/day was associated with minor changes only. These included salivation, changes in coat condition, marginal reductions in red blood cell values (dubious biological significance), the presence of ketones in the urine (males only; possibly resulting from breakdown products of the test substance) as well as slightly raised liver and adrenal weight (females only; no histopathologic correlate). Bodyweight gain and food intake were unaffected by treatment. In conclusion, the NOAEL of Pyranol for repeated dose toxicity study in rats was defined as 125 mg/kg bw/day and the LOAEL as 625 mg/kg bw/day

In order to address the potential for reproduction toxicity of Pyranol, the test substance was administered to groups of 25 male and 25 female healthy young Wistar rats (F0 parental generation) as a homogeneous addition to the food in different concentrations (0, 1000, 4000 and 12500 ppm; corresponding to approx. 0 mg/kg bw/d, 100 mg/kg bw/d, 300 mg/kg bw/d and 1000 mg/kg bw/d) during an Extended One-Generation Reproduction Toxicity Study according to OECD 443 and GLP (BASF SE, 2018).

There were no test substance-related mortalities or adverse clinical observations noted in any of the groups. In particular, regularly conducted detailed clinical observations revealed no effects. The high-dose of the test substance (12500 ppm) produced some signs of adverse systemic effects in the F0 parental rats and F1 offspring. In the 12500 ppm F0 females food consumption was consistently reduced during lactation. In contrast to this food consumption in the 1000 ppm and 4000 ppm F0 females as well as in the F0 males and F1 adolescents (Cohort 1A and 1B) of all dose groups remained unchanged. Body weights and body weight change of all test substance-treated male and female F0 rats were essentially comparable to the concurrent control values throughout the entire study. The final body weights of the high-dose F0 males and females (12500 ppm) were marginally (approximately 3-5%) below control, but as the difference was not statistically significant and very small it could not be attributed to the treatment without doubt.

In contrast body weights and, particularly, body weight change of the F1 high-dose (12500 ppm) Cohort 1A and Cohort 1B males and females were consistently below the concurrent control throughout the in-life period. The body weight difference gained statistical significance usually towards the end of their study and final weights were about 5-7% below control. The F1 high-dose adolescents of both cohorts generally gained 7-10% less body weight than the control throughout in-life. Pup body weight development of the high-dose offspring (12500 ppm) was affected by the treatment towards the end of lactation, as these offspring weighed about 5-7% less than control at weaning (PND 21) and their weights were below the historical control range. Accordingly, there was no test compound-related influence on high-dose F1 pup body weight change until PND 14. In the last week of lactation (PND 14 – 21), however, the mean body weight change of these pups was statistically significantly below the concurrent control values (about 9% for both sexes) which crucially contributed to the overall lower weight gain (about 6% for both sexes) of this test group throughout lactation. During the last week of lactation the offspring already consume considerable amounts of medicated diet and the post-weaning body weight gain of the high-dose adolescents in the F1A and B cohorts continued to be lower compared to the control. Thus, it can be assumed that the lower pre-weaning body weights/body weight gain in the high-dose group were caused by direct exposure of the offspring to the test compound through the diet rather than representing developmental toxicity. In addition, the pup body weight effects had no influence on postnatal pup survival or well-being, neither during early lactation nor later, as clinical and/or gross necropsy examinations of the high-dose F1 pups revealed no adverse findings. There is evidence that the rather small difference to the control indicates that the later onset of puberty is most likely a consequence of systemic toxicity and subsequent general developmental delay, and not a specific effect on the timing of puberty.

Thus, under the conditions of the present extended one-generation reproduction toxicity study the NOAEL (no observed adverse effect level) for general, systemic toxicity is 4000 ppm (about 359 mg/kg bw/d), based on decreased food consumption and body weight/body weight gain at 12500 ppm, in the F0 parental females as well as adolescent and adult F1 offspring. The NOAEL for fertility and reproductive performance for the parental rats is 12500 ppm (about 1113 mg/kg bw/d), the highest tested dose. The NOAEL for developmental toxicity in the F1 progeny is 12500 ppm (about 1113 mg/kg bw/d), the highest tested dose. Lower pup body weights/body weight gain in the high-dose pups shortly before weaning as well as a small delay of puberty in females were caused by systemic toxicity of the test substance after direct exposure through the diet and do not represent developmental toxicity.

As supporting information, data on a screening test for reproduction/developmental toxicity in rats according to OECD 421 and GLP is available. Ten male and ten female Wistar rats per dose received Pyranol at doses of 0, 100, 300 and 1000 mg/kg/d by semi occlusive dermal application with corn oil as vehicle. After the mating period, the male animals were sacrificed while the females were allowed to litter and rear their pups until day 4 post partum. No test substance-related effects were observed concerning body weight and food consumption. Vaginal discharge was detected in single animals of the control as well as the treated groups during mating phase. One female of the control group showed piloerection during gestation phase. These findings were assessed as being incidental in nature since they occurred in individual animals only and did not show a dose-response relationship. No effects on parental organ weights and gross- and histopathological findings as well as offspring examinations were observed. Thus, under the conditions of this reproduction/developmental toxicity screening study the NOAEL for general systemic toxicity as well as reproductive performance and fertility in male and female Wistar rats was 1000 mg/kg bw/d.

Furthermore, Pyranol was administered by gavage (olive oil as vehicle) over a period of 14 days at 1000 mg/kg bw/day to 5 male young Wistar rats to obtain initial information on the effect of the test substance on male sexual organs after repeated oral administration (BASF SE 2010, 06R0725/06056). All animals were assessed by gross pathology, special attention being given to the reproductive organs. Salivation was observed after treatment in all animals. Neither sperm evaluation nor gross pathology and histopathology of male sexual organs revealed treatment-related findings in the animals exposed to Pyranol. No treatment-related adverse effects regarding the male reproductive organs were observed in this study.

A dermal pre-natal developmental toxicity study in rats with Pyranol according to OECD 414 and GLP was conducted (BASF SE 2015, 33R0639/09R142). The test substance was given daily dermally (6 hours/day) as an oily solution to groups of 25 time-mated female Wistar rats at dose levels of 100, 300 and 1000 mg/kg body weight/day (mg/kg bw/d) to the intact shaven dorsal skin using a semi-occlusive dressing on gestation days (GD) 6 through 19. The control group, consisting of 25 females, was dosed with the vehicle (corn oil) in parallel. No test substance-related, adverse effects were noted at any dose group. In conclusion, the NOAEL for maternal toxicity was 1000 mg/kg bw/d, the highest dose tested. The NOAEL for parental developmental toxicity was also 1000 mg/kg bw/d. No toxicologically relevant adverse fetal findings were evident.

Therefore, the NOAEL (oral) of 300 mg/kg bw/day in the Extended One-Generation Reproduction Toxicity Study and the NOAEL (dermal) of 1000 mg/kg bw/day in the 90-days repeated dose toxicity study have been taken as point of departure for the respective systemic DNELs derived, which covers findings observed in the subacute repeated dose and reproduction/developmental toxicity study.

Route to route extrapolation:

On the basis of the low vapour pressure 0.01 hPa), the exposure with Pyranol via inhalation as a vapour is low. According to Chapter R.8 of REACH Guidance on information requirements and chemical safety assessment, it is proposed in the absence of route-specific information to include a default factor in the case of inhalation-to-oral extrapolation, assuming 50% oral and 100% inhalation absorption.

Substance specific assessment factor for remaining differences:

Although ‘residual’ interspecies variability may remain following allometric scaling, this is largely accounted for in the assessment factors proposed for intraspecies variability, i.e. reflecting the interdependency of inter- and intraspecies assessment factors (Calabrese and Gilbert, 1993).

Furthermore, within the ERASM project, it was suggested that a factor of 2.5 for ‘remaining‘ interspecies differences may be questionable as a standard procedure (Escher and Mangelsdorf, 2009; Batkeet al, 2010; Bitsch et al, 2006). The comparison of rats and mice indicated an interspecies difference of 1.4 for these two species. This corresponds closely to an interspecies AF solely explained by allometry (7:4 = 1.75) without an additional factor of 2.5 for putative toxicodynamic differences.

Based on the availability of a sufficient toxicity dataset, the default assessment factors (acc. to ECHA GD R8) can be modified into substance specific assessment factors (AF) considering the intrinsic hazard properties of the registered substance. The following findings form the basis of the rationale for the substance specific AF:

In a dermal subchronic study (according to OECD 411 and GLP) some animals showed slight erythema, erosion and scales. These finding are attributed to the irritating properties of the test substance. No other test substance-related effects concerning clinical signs, body weight food consumption, water consumption, haematology, clinical chemistry, urinalysis, neurobehaviour, organ weights and histopathology were observed. In an Extended One-Generation Reproduction Toxicity Study (according to OECD 443 and GLP) food consumption was consistently reduced during lactation in the high-dose F0 females. Body weight change of the F1 high-dose Cohort 1A and Cohort 1B males and females were consistently below the concurrent control throughout the in-life period. The F1 high-dose adolescents of both cohorts generally gained 7-10% less body weight than the control throughout in-life. Pup body weight development of the high-dose offspring (12500 ppm) was affected by the treatment towards the end of lactation, as these offspring weighed about 5-7% less than control at weaning (PND 21). In the dermal reproduction/developmental toxicity screening test (according to OECD 421 and GLP) and the dermal pre-natal developmental toxicity study (according to OECD 414 and GLP) no test substance-related, adverse effects were noted in the parental animals and the pups up to the limit dose of 1000 mg/kg bw/d.

In the key studies given above, the nature of effects observed are based on either adaptive or unspecific systemic adverse effects such as reduced food consumption and body weight, salivation, changes in coat condition as well as slightly raised liver and adrenal weights. In order to add sufficient conservatism into the DNEL derivation, namely to cover for the uncertainty of a putative systemically toxic parent compound/metabolite being excreted dependent on the caloric demand, an AF of 4 for allometric scaling is included for oral/ dermal systemic long term DNELs.

Since no human relevant organ specific toxicity has been observed, no additional AF covering toxicodynamic differences between rats and humans are considered necessary. In fact, an underestimation of interspecies differences between rats and humans beyond allometric scaling is unlikely due to the favorable toxicological profile of the registered substance.

It needs further to be pointed out, that the multiplicatory principle of different AFs used further adds to conservatism in the derivation of the respective DNELs, especially for the registered substance, which contains a toxicological profile, justifying a non-classification according to 67/548/EEC and regulation (EU) 1272/2008.

Substance specific assessment factor for intraspecies extrapolation

Studies on the distribution of human data for various toxicokinetic and toxicodynamic parameters were taken into account, including ‘healthy adults’ of both sexes, young and elderly, mixed races and patients with various medical conditions such as cancer and hypertension. (Hattis 1987, 1999; Hattis and Silver 1994; Renwick and Lazarus, 1998). Using the 95th percentile of the combined distribution of the toxicokinetic and -dynamic variability of datasets is a statistical approach to account for intraspecies variability based on toxicological datasets. On the basis of the above mentioned assessments and statistical approach, an AF of 5 for the general population and AF factor of 3 for the more homogenous worker population can be estimated to account for intraspecies variability.

It needs further to be pointed out, that the multiplicatory principle of AF used further adds to conservatism in the derivation of the respective DNELs, especially for the registered substance, which contains a toxicological profile, justifying a non-classification according to 67/548/EEC and regulation (EU) 1272/2008.

Based on the availability of a sufficient toxicity dataset, the default assessment factors (acc. to ECHA GD R8) can be modified into substance specific assessment factors (AF) considering the intrinsic hazard properties of the registered substance. The following findings form the basis of the rationale for the substance specific AF:

In a dermal subchronic study (according to OECD 411 and GLP) some animals showed slight erythema, erosion and scales. These finding are attributed to the irritating properties of the test substance. No other test substance-related effects concerning clinical signs, body weight food consumption, water consumption, haematology, clinical chemistry, urinalysis, neurobehaviour, organ weights and histopathology were observed. In an Extended One-Generation Reproduction Toxicity Study (according to OECD 443 and GLP) food consumption was consistently reduced during lactation in the high-dose F0 females. Body weight change of the F1 high-dose Cohort 1A and Cohort 1B males and females were consistently below the concurrent control throughout the in-life period. The F1 high-dose adolescents of both cohorts generally gained 7-10% less body weight than the control throughout in-life. Pup body weight development of the high-dose offspring (12500 ppm) was affected by the treatment towards the end of lactation, as these offspring weighed about 5-7% less than control at weaning (PND 21). In the dermal reproduction/developmental toxicity screening test (according to OECD 421 and GLP) and the dermal pre-natal developmental toxicity study (according to OECD 414 and GLP) no test substance-related, adverse effects were noted in the parental animals and the pups up to the limit dose of 1000 mg/kg bw/d.

In the key studies given above, the nature of effects observed are based on either adaptive or unspecific systemic adverse effects such as reduced salivation, changes in coat condition as well as slightly raised liver and adrenal weights. No human relevant organ specific toxicity is identified for the registered substance, which would justify a conservative default assessment factor for intraspecies variations in toxicokinetics or toxicodynamics. However, an AF of 3 or 5 has been included to cover for remaining uncertainties within a controlled subpopulation, i.e. healthy workers or the general population, respectively.

For the worker, the following DNELs were derived:

For derivation of the long-term systemic inhalative DNEL of Pyranol, the oral systemic no adverse effect level, i.e. 300 mg/kg bw/d was taken as a basis and converted into a corrected inhalative NOAEC of 264.5 mg/m³according to the procedure, recommended in the current guidance document (R8, ECHA 2012). Applying all assessment factors, the inhalative long-term systemic DNEL was set at 44.1 mg/m³for the worker.

Long-term – inhalation, systemic effects

Description	Value	Remark
Step 1) Relevant dose-descriptor	NOAEL: 300 mg/kg bw/d
Step 2) Modification of starting point	50%/100% 0.38 m³/kg bw 6.7 m³/10 m³	Ratio of oral (rat) to inhalation (human) absorption (default value, as proposed in the REACH guidance (R.8.4.2) Standard respiratory volume of a rat, corrected for 8 h exposure, as proposed in the REACH Guidance (R.8.4.2) Correction for activity driven differences of respiratory volumes in workers compared to workers in rest (6.7 m³/10 m³).
Modified dose-descriptor	NOAEC corrected inhalative = 300 * (50/100) * (1/0.38) * (6.7/10) = 264.5 mg/m³
Step 3) Assessment factors
Allometric scaling	1	No allometric scaling has to be applied in case of oral to inhalation route to route extrapolation according to R8 ECHA 2008.
Remaining differences	1	Substance specific assessment factor (see justification above)
Intraspecies	3	Substance specific assessment factor (see justification above)
Exposure duration	2	Use of a subchronic study as starting point forlong-term systemic DNEL derivation (default assessment factor according to R8 ECHA 2012)
Dose response	1	according to R8 ECHA 2012
Quality of database	1	according to R8 ECHA 2012 (GLP guideline Study)
DNEL	Value
	264.5 / (1 x 1 x 3 x 2 x 1 x 1) =44.1mg/m³

For derivation of the long-term systemic dermal DNEL of Pyranol, the dermal systemic no adverse effect level, i.e. 1000 mg/kg bw/d was taken as a basis. Applying all assessment factors, the dermal long-term systemic DNEL derived was 41.7 mg/kg bw/d for the worker.

Long-term – dermal, systemic effects

Description	Value	Remark
Step 1) Relevant dose-descriptor	NOAEL: 1000 mg/kg bw/d
Step 2) Modification of starting point	-
Modified dose-descriptor	NOAEL corrected dermal = 300 mg/kg bw/d
Step 3) Assessment factors
Allometric scaling	4	Assessment factor for allometric scaling according to R8 ECHA 2012
Remaining differences	1	Substance specific assessment factor (see justification above)
Intraspecies	3	Substance specific assessment factor (see justification above)
Exposure duration	2	Use of a subchronic study as starting point forlong-term systemic DNEL derivation (default assessment factor according to R8 ECHA 2012)
Dose response	1	according to R8 ECHA 2012
Quality of database	1	according to R8 ECHA 2012
DNEL	Value
	300 / (4 x 1 x 3 x 2 x 1 x 1) =41.7 mg/kg bw/d

No DNELs were derived for

- systemic effects after short term inhalative or dermal exposure,

- local effects after short term or long term inhalative or dermal exposure,

as the substance exhibits no hazardous potential in terms of these endpoints and the conservatively derived long term inhalative and dermal DNELs for systemic effects cover putative short term systemic effects as well as short and long term local effects.

Furthermore, Pyranol is not a skin irritant but classified as “eye irritant” (category 2) according to 1272/2008/EEC and “irritating to eye” (R36) according to 67/548/EEC. Since no quantitative data addressing the hazard of eye irritation are available, a respective no effect concentration cannot be derived and included in the derivation of the short term/long term local dermal DNEL. However, a qualitative risk characterization including the implementation of suitable risk management measures is performed in the CSR.

Hazard assessment conclusion:

DNEL (Derived No Effect Level)

Value:

13 mg/m³

Most sensitive endpoint:

repeated dose toxicity

Route of original study:

Oral

Overall assessment factor (AF):

10

Modified dose descriptor starting point:

NOAEC

Value:

130.4 mg/m³

Hazard assessment conclusion:

no hazard identified

Hazard assessment conclusion:

no hazard identified

Hazard assessment conclusion:

no hazard identified

Hazard assessment conclusion:

DNEL (Derived No Effect Level)

Value:

25 mg/kg bw/day

Most sensitive endpoint:

repeated dose toxicity

Route of original study:

Dermal

Overall assessment factor (AF):

40

Modified dose descriptor starting point:

NOAEL

Value:

1 000 mg/kg bw/day

Hazard assessment conclusion:

no hazard identified

Hazard assessment conclusion:

no hazard identified

Hazard assessment conclusion:

no hazard identified

Hazard assessment conclusion:

DNEL (Derived No Effect Level)

Value:

7.5 mg/kg bw/day

Most sensitive endpoint:

repeated dose toxicity

Route of original study:

Oral

Overall assessment factor (AF):

40

Modified dose descriptor starting point:

NOAEL

Value:

300 mg/kg bw/day