Phthalic acid

Endpoint summary

Key value for chemical safety assessment

Effects on fertility

Description of key information

In a subacute repeated dose oral toxicity study in male Wistar rats the test animals were given a powder diet containing phthalic acid (PA) at a level of 0.5 or 5% for 34 to 36 days, respectively. No histopathologic effect or decrease in testicle weight could be observed (Murakami, 1986). Additionally in an insufficient documented, oral repeated dose toxicity study in young male 3 -4 weeks old (70 -100g) albino rats of the Sprague-Dawley strain for 4 days, the treatment did not affect the testicular tissues of rats (Cater, 1977).

Histopathological examinations in chronic repeated dose toxicity studies on rats and mice performed with phthalic anhydride indicated no effects on reproductive organs. Consequently no effects on reproduction are anticipated.  

A testing proposal for an Extended One Generation Study (OECD TG 443) is included based on read-across with phthalic anhydride. Phthalic anhydride rapidly hydrolyses in contact with water to phthalic acid.

Link to relevant study records

Reference

Reference 1

Endpoint:

extended one-generation reproductive toxicity - basic test design (Cohorts 1A, and 1B without extension)

Type of information:

experimental study planned (based on read-across)

Remarks:

An OECD TG 414 study in the rabbit by the oral route of exposure is proposed as per REACH Annex X, Section 8.7.2 for phthalic anhydride (CAS-No. 85-44-9). For justification see RAAF document attached to this registration dossier.

Study period:

An OECD TG 414 study in the rabbit by the oral route of exposure is proposed as per REACH Annex X, Section 8.7.2 for phthalic anhydride (CAS-No. 85-44-9). The test period will be established once the ECHA approves this Test Proposal.

Justification for type of information:

TESTING PROPOSAL ON VERTEBRATE ANIMALS
Reproductive toxicity (extended one-generation reproductive toxicity study, EOGRTS, OECD 443) with the registered substance.

NON-CONFIDENTIAL NAME OF SUBSTANCE:
- Name of the substance on which testing is proposed to be carried out:
phthalic anhydride (CAS 85-44-9)

- Name of the substance for which the testing proposal will be used [if different from tested substance]
Phthalic anhydride will be used if technically feasible. Since phthalic anhydride is rapidly hydrolyzed in aqueous vehicles to phthalic acid, the use of the hydrolysis product phthalic acid (CAS 88-99-3) will be considered after appropriate documentation.


CONSIDERATIONS THAT THE GENERAL ADAPTATION POSSIBILITIES OF ANNEX XI OF THE REACH REGULATION ARE NOT ADEQUATE TO GENERATE THE NECESSARY INFORMATION [please address all points below]:

- Available GLP studies:
No GLP studies for substance are available to cover the endpoint ‘reproductive toxicity’. The available repeated dose toxicity studies were performed before 1979 and the GLP status is thus not given.

- Available non-GLP studies:
Studies with relevance for reproduction toxicity:
There are two chronic repeated dose toxicity studies available in which rats or mice were fed a diet containing phthalic anhydride. In these studies phthalic anhydride has been shown to have low repeated dose toxicity by the oral route. The dosing periods comprised 105 weeks (NCI, 1979). Additionally, dose-range finding studies for the 2-year studies with exposure of rats and mice for 7 weeks are available (NCI, 1979). Due to the time of performance the studies the GLP status is not given for these studies. There are no relevant repeated inhalation toxicity studies or dermal toxicity studies available.
In the rat chronic carcinogenicity study, groups of 50 Fischer 344 rats per sex were exposed to 7500 or 15 000 ppm (approximately 500 and 1000 mg/kg bw/day) of phthalic anhydride in the diet (NCI, 1979). The control group consisted of 20 animals per sex. At termination, after 105 weeks, all major organs were macroscopically and microscopically examined. No treatment-related differences in mortality or microscopic changes among the groups became obvious. The only effect was a slight reduction of bodyweight gain of the high dose males of below 10%. The survival rate was not affected and was overall ≥ 70 %. No hematology and no clinical chemistry endpoints were examined. The evidence of toxicity in this chronic rat study was limited to adverse effects on body-weight gain at the dose level of approximately 1000 mg/kg bw/day. The NOAEL for repeated dose toxicity was 500 mg/kg bw/day.
No evidence of toxicity to reproductive organs was observed in this carcinogenicity study, as no treatment-related changes were observed for any reproductive organ investigated during macroscopic and microscopic examination, i.e. preputial gland, prostate, seminal vesicle, testis and epididymis, mammary gland in male rats, and mammary gland, uterus, endothelial gland, ovary in female rats. The NOAEL for reproduction toxicity in this rat study was determined with 1000 mg/kg bw/day (time-weighted average),

In the mouse chronic carcinogenicity study, groups of 50 treated B6C3F1 mice of each sex were exposed via food at levels of 0, 25 000, or 50 000 ppm for the first 32 weeks of a 104 week treatment period (approximately 3570 or 7140 mg/kg bw/day). The control group comprised 20 animals per sex. Because of excessive body weight loss during the first 32 weeks the exposure levels in male mice were reduced. The time-weighted average doses for the males were approximately 2340 or 4670 mg/kg bw/day and approximately 1717 or 3430 mg/kg bw/day for females. A dose-related reduction in bodyweight gain was observed throughout the study with terminal bodyweights reduced by 12 and 27 % compared to controls for the low and high dose groups, respectively. The survival rate at the end of the treatment period was at least 74 % in all groups. Histopathology of reproductive relevant organs were performed on epididymis in male mice and uterus and ovary of female mice and showed no treatment related changes. The NOAELs for reproduction toxicity in this study 3430 mg/kg bw/day for female mice and 4670 mg/kg bw/day for male mice.

No valid developmental toxicity/teratogenicity study with phthalic anhydride is available. However, phthalic anhydride is known to undergo rapid hydrolysis to phthalic acid on contact with water. The kinetic of the hydrolysis of phthalic anhydride was shown to be 30.5 seconds at pH 7.24 and 25 °C, 52.5 seconds at pH 6.8 and 75 seconds at pH 0 - 6 and 25°C (range 66.6 to 79.5 seconds) (Andres, 2001). It is likely that a similar reaction will occur in biological systems, which is supported by the presence of unconjugated phthalic acid in the urine of workers occupationally exposed to phthalic anhydride (Pfaeffli, 1986). Thus, a read-across with data obtained for the acid is considered adequate.

No valid developmental toxicity/teratogenicity study with phthalic anhydride is available. A hydrolysis study has shown that phthalic anhydride rapidly hydrolyses to phthalic acid (CAS-No. 88-99-3) under aqueous conditions. In the presence of water phthalic anhydride hydrolyses rapidly forming phthalic acid. The kinetic of the hydrolysis of phthalic anhydride was studied to be 30.5 seconds at pH 7.24 and 25 °C. At pH 8.9 the half-life of phthalic anhydride in water dropped to 2.4 seconds (Andres et al., 2001).
Thus, phthalic anhydride would be rapidly hydrolyzed to phthalic acid in the gastrointestinal tract after ingestion and thus, phthalic acid can be considered as the relevant toxicity driver in animals and humans after oral uptake. A read-across of toxicological data from phthalic anhydride to the acid and vice versa is thus considered adequate. (see RAAF Document attached to the dossier)

Phthalic acid was investigated in a developmental toxicity feeding study. Groups of eleven pregnant rats were fed a diet containing phthalic anhydride at a dose of 0, 1.25, 2.5, or 5.0% (approximately 0, 1021, 1763, 2981 mg/kg bw/day) ad libitum on GD 7 - 16. The pregnant rats were observed daily for evidence of clinical signs of toxicity, maternal body weight and food consumption. Average daily intake of phthalic acid was calculated. The pregnant rats were sacrificed on day 20 of pregnancy. The peritoneal cavity and uterus were opened and the numbers of live and dead fetuses and resorptions were counted. The live fetuses removed from the uterus were sexed, weighed and inspected for external malformations and malformations within the oral cavity. Approximately two-thirds of live fetuses in each litter, randomly selected, were stained and examined for skeletal malformations. The remaining live fetuses in each litter were fixed and examined for internal malformations. Maternal toxicity occurred in the 2.5 and 5% groups. Significant decreases in the weight of male fetuses and decreased numbers of ossified centers of the caudal vertebrae were found only in the 5% group, where significant maternal toxicity was observed.
Therefore, in this study the NOAEL for developmental toxicity was 2.5% in feed (= approximately 1763 mg/kg bw/day) and the NOAEL for maternal toxicity was 1.25% in feed (= approximately 1021 mg/kg bw/day).
Based on the data of phthalic acid, the hydrolysis product of phthalic anhydride, it can be concluded that, in the absence of maternal toxicity, phthalic anhydride is not a developmental toxicant.

Further repeated dose toxicity studies:
Two 7-week repeated dose toxicity studies were conducted in Fischer 344 rats and B6C3F1 mice as dose-range finding studies for the carcinogenicity studies described above. Groups of five animals of each sex were exposed to phthalic anhydride via the diet at levels of 0, 6200, 12 500, 25 000, and 50,000 ppm (approximate doses in rats: 0, 410, 830, 1660, and 3330 mg/kg bw/day; mice: 0, 890, 1790, 3570, and 7140 mg/kg bw/day). Body weights were recorded throughout the study and unspecified tissues were examined microscopically. In rats, there was a significant reduction in body-weight gain (approximately 75 % weight gain compared to controls at seven weeks) at the highest dose level (50,000 ppm). At 25 000 ppm, centrilobular cytoplasmic vacuolation were seen in the livers of four male rats; although tissues were essentially normal in all rats at 50 000 ppm. In mice no effect on body weight was observed at any dose, and there were no microscopic abnormalities in any mice at all dose levels (NCI, 1979).

- historical human data
No human data are available to cover the endpoint reproduction toxicity – fertility.

- (Q)SAR
no reliable data available; there is no QSAR model available which is accepted by ECHA for the endpoint reproductive toxicity - fertility.
According to DART (Developmental And Reproduction Toxicity) scheme profiler of the QSAR Toolbox 4.4 query of June 2020 phthalic anhydride and phthalic acid are not associated with chemical structures known to have DART, thus, phthalic anhydride and phthalic anhydride are not foreseen as developmental or reproductive toxicants.
The toxic hazard classification by Cramer (and Cramer extended) obtained in the QSAR Toolbox is predicted with high hazard for phthalic anhydride based on the reactive aldehyde group (Cramer class III) and low hazard for phthalic acid after hydrolysis (Cramer class I).

- In vitro methods
no reliable data available; there are no in vitro methods available which are accepted by ECHA for the endpoint reproductive toxicity - fertility

- Weight of evidence
No specific studies on fertility are available for phthalic anhydride or the hydrolysis product phthalic acid. A chronic feeding study in rats with histopathological examination of preputial gland, prostate, seminal vesicle, testis and epididymis, and mammary gland in male rats, and mammary gland, uterus, endothelial gland, and ovary in female rats revealed no evidence of an adverse effect on the reproductive organs up to the highest doses tested (approx. 1000 mg/kg bw/day). Based on the available data there is no reason to expect specific reproductive toxicity of phthalic anhydride.
Phthalic acid, the hydrolysis product of phthalic anhydride, was tested in a developmental toxicity feeding study in rats in oral doses of up to 2981 mg/kg bw/day. Maternal toxicity occurred in the two highest dose groups of 2.5 and 5% phthalic acid in food. Significant decreases in the weight of male fetuses and decreased numbers of ossified centers of the caudal vertebrae were found only in the 5% group, where significant maternal toxicity was observed. Therefore, in this study the NOAEL for developmental toxicity was 2.5% in feed (= approximately 1763 mg/kg bw/day) and the NOAEL for maternal toxicity was 1.25% in feed (= approximately 1021 mg/kg bw/day). Based on the data of phthalic acid, the hydrolysis product of phthalic anhydride, it can be concluded that, in the absence of maternal toxicity, phthalic anhydride is not a developmental toxicant.
The OECD QSAR Toolbox version 4.4 does not identify any chemical structures that point to a reproductive toxicity potential (DART profiler) for phthalic anhydride and phthalic acid.
Based on this assessment and on the fact that there is no indication for a reproductive toxicity hazard of phthalic anhydride, the registrant would like to point out that this EOGRTS testing proposal is prepared solely because of formal data requirements. On a scientific basis, the available toxicological information for phthalic anhydride, showing an overall uncritical systemic toxicity profile, is considered sufficient to cover the endpoint reproductive toxicity.

- Grouping and read-across
There are no read-across compounds with adequate data bases for reproductive toxicity available to cover the endpoint fertility.
A hydrolysis study has shown that phthalic anhydride rapidly hydrolyses to phthalic acid (CAS-No. 88-99-3) under aqueous conditions. In the presence of water phthalic anhydride hydrolyses rapidly forming phthalic acid. The kinetic of the hydrolysis of phthalic anhydride was studied to be 30.5 seconds at pH 7.24 and 25 °C. At pH 8.9 the half-life of phthalic anhydride in water dropped to 2.4 seconds (Andres et al., 2001). Thus, phthalic anhydride would be rapidly hydrolyzed to phthalic acid in the gastrointestinal tract after ingestion and thus, phthalic acid can be considered as the relevant toxicity driver in animals and humans after oral uptake. A read-across of toxicological data from phthalic anhydride to the acid and vice versa is thus considered adequate. (see RAAF Document attached to the dossier)
No EOGRTS or comparable reproductive toxicity study is available for phthalic acid, therefore, phthalic acid cannot be used as source for fertility data in a read-across approach. However, the results obtained in the EOGRTS with phthalic anhydride are intended to be included in the dossier of phthalic acid. The proposed EOGRTS with phthalic anhydride will be used to fill the data gap for reproduction toxicity study of phthalic acid in a read-across approach as source. Thus, the EOGRTS with phthalic anhydride will not only serve for the assessment of phthalic anhydride but also, via read-across, for the assessment of phthalic acid.

- Substance-tailored exposure driven testing [if applicable]
not applicable.

- Approaches in addition to above [if applicable]
not applicable.

- Other reasons [if applicable]
not applicable.

CONSIDERATIONS THAT THE SPECIFIC ADAPTATION POSSIBILITIES OF ANNEXES VI TO X (AND COLUMN 2 THEREOF) OF THE REACH REGULATION ARE NOT ADEQUATE TO GENERATE THE NECESSARY INFORMATION:
There is no EOGRTS or multi-generation study for phthalic anhydride available and the adaptation options as defined in Annexes VI to X (and column 2 thereof) are, on a formal basis, not applicable for this substance and this endpoint.
Therefore, as none of the general and specific adaption rules in column 2 provide possibilities for omitting the testing and testing is technically feasible, there is no other option to formally fulfil the requirements than to conduct the extended one generation reproductive toxicity study with phthalic anhydride or, if technically not feasible, with phthalic acid, to fulfill the requirements.

FURTHER INFORMATION ON TESTING PROPOSAL IN ADDITION TO INFORMATION PROVIDED IN THE MATERIALS AND METHODS SECTION:
- Details on study design / methodology proposed [if relevant]
An Extended One-Generation Reproductive Toxicity Study (OECD 443) - basic test design (Cohorts 1A, and 1B without extension) with oral application - is proposed by the registrant for formal reasons (no EOGRTS or multi-generation study available). On a scientific basis, the available toxicological information for phthalic anhydride and phthalic acid, showing overall uncritical systemic toxicity profiles, is considered sufficient to cover the endpoint reproductive toxicity.

Justification for study design
SPECIFICATION OF STUDY DESIGN FOR EXTENDED ONE-GENERATION REPRODUCTION TOXICITY STUDY WITH JUSTIFICATIONS [please address all points below]:

- Premating exposure duration for parental (P0) animals
Pre-mating exposure duration will be 10 weeks to cover the full spermatogenesis and folliculogenesis before the mating in accordance with ECHA Guidance R7a, Appendix R.7.6-3

- Basis for dose level selection
There are two repeated dose toxicity studies available in which rats were fed a diet containing phthalic anhydride. The dosing periods comprised 7 weeks in the dose-range finding study for the chronic study (NCI, 1979) and 2 years in the main study (NCI, 1979). The NOAEL in the most relevant 2-year study was 7500 ppm for rats (approx. 500 mg/kg bw/day) and higher doses caused body weight retardation with no indication of specific target organ toxicity. The dose selection for the EOGRTS will be based on this information, ensuring that toxicity in both female and male animals is considered.

- Inclusion/exclusion of extension of Cohort 1B
Guidance on Information Requirements and Chemical Safety Assessment Chapter R.7a: Endpoint specific guidance, Appendix R.7.6–1 A provides a check list for information that contributes to EOGRTS design. Examination of the available data indicate that extension to include the F2 generation is not justified, since:
• the substance does not display genotoxic effects in somatic cell mutagenicity tests in vivo which could lead to classifying it as Mutagen Category 2
• there are no indications that the internal dose for the substance and/or any of its metabolites will reach a steady state in the test animals only after an extended exposure. The physico-chemical properties (high water solubility and hydrolyzing to phthalic acid; log Kow of 0.73 at pH 1 for phthalic acid) and the excretion behavior do not indicate any bioaccumulation potency.
• there are no indications of one or more relevant modes of action related to endocrine disruption from available in vivo studies or non-animal approaches.

- Termination time for F2
Not appropriate

- Inclusion/exclusion of developmental neurotoxicity Cohorts 2A and 2B
Guidance on Information Requirements and Chemical Safety Assessment Chapter R.7a: Endpoint specific guidance, Appendix R.7.6–1 A provides a check list for information that contributes to EOGRTS design. Examination of the available data indicate that extension to include cohorts 2A/2B (developmental neurotoxicity) is not justified.

- Inclusion/exclusion of developmental neurotoxicity Cohorts 2A and 2B
Based on the available data an extension to include cohorts 2A/2B (developmental neurotoxicity) is not justified.

- Inclusion/exclusion of developmental immunotoxicity Cohort 3
Guidance on Information Requirements and Chemical Safety Assessment Chapter R.7a: Endpoint specific guidance, Appendix R.7.6–1 A provides a check list for information that contributes to EOGRTS design. Examination of the available data indicate that extension to include cohort 3 (developmental immunotoxicity) is not justified.

- Route of administration
Oral route, as technically feasible

- Other considerations, e.g. on choice of species, strain, vehicle and number of animals [if applicable]
Oral route as technically feasible. In case no stability can be achieved the use of the hydrolysis product phthalic acid (CAS 88-99-3) will be considered after appropriate documentation.


For further information see attached document:
Justification for a read-across between phthalic acid and phthalic anhydride

Guideline:

OECD Guideline 443 (Extended One-Generation Reproductive Toxicity Study)

Justification for study design:

SPECIFICATION OF STUDY DESIGN FOR EXTENDED ONE-GENERATION REPRODUCTION TOXICITY STUDY WITH JUSTIFICATIONS [please address all points below]:

- Premating exposure duration for parental (P0) animals
Pre-mating exposure duration will be 10 weeks to cover the full spermatogenesis and folliculogenesis before the mating in accordance with ECHA Guidance R7a, Appendix R.7.6-3

- Basis for dose level selection
There are two repeated dose toxicity studies available in which rats were fed a diet containing phthalic anhydride. The dosing periods comprised 7 weeks in the dose-range finding study for the chronic study (NCI, 1979) and 2 years in the main study (NCI, 1979). The NOAEL in the most relevant 2-year study was 7500 ppm for rats (approx. 500 mg/kg bw/day) and higher doses caused body weight retardation with no indication of specific target organ toxicity. The dose selection for the EOGRTS will be based on this information, ensuring that toxicity in both female and male animals is considered.

- Inclusion/exclusion of extension of Cohort 1B
Based on the available data an extension to include the F2 generation is not justified, since

• the substance does not display genotoxic effects in somatic cell mutagenicity tests in vivo which could lead to classifying it as Mutagen Category 2
• there are no indications that the internal dose for the substance and/or any of its metabolites will reach a steady state in the test animals only after an extended exposure. The physico-chemical properties (high water solubility and hydrolyzing to phthalic acid; log Kow of 0.73 at pH 1 for phthalic acid) and the excretion behavior do not indicate any bioaccumulation potency.
• there are no indications of one or more relevant modes of action related to endocrine disruption from available in vivo studies or non-animal approaches.

- Termination time for F2
Not appropriate

- Inclusion/exclusion of developmental neurotoxicity Cohorts 2A and 2B
Based on the available data an extension to include cohorts 2A/2B (developmental neurotoxicity) is not justified.

- Inclusion/exclusion of developmental immunotoxicity Cohort 3
Based on the available data an extension to include cohort 3 (developmental immunotoxicity) is not justified.

- Route of administration
Oral route, as technically feasible

- Other considerations, e.g. on choice of species, strain, vehicle and number of animals [if applicable]
Oral route as technically feasible. In case no stability can be achieved the use of the hydrolysis product phthalic acid (CAS 88-99-3) will be considered after appropriate documentation.

Species:

rat

Sex:

male/female

Route of administration:

other: oral, most appropriate application route

Reference 2

Endpoint:

reproductive toxicity, other

Remarks:

reproductive organs in a 2 years study were examined

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: well documented and scientifically acceptable

Principles of method if other than guideline:

Groups of 50 rats of each sex were administered phthalic anhydride at one of 2 doses, either 7.500 or 15.000 ppm (ca. 500, 1000 mg/kg bw/d) for 105 weeks. Matched controls consisted of 20 untreated rats of each sex
At the end all animals were killed using CO2 inhalation and necropsied; gross and microscopic examination of: all major organs, including reproductive organs; in male rats preputial gland, prostate, seminal vesicle, testis and epididymis, and the mammary gland; in female rats mammary gland, uterus, endothelial gland, and ovary.

GLP compliance:

not specified

Species:

rat

Strain:

Fischer 344

Sex:

male/female

Route of administration:

oral: feed

Vehicle:

other: diet

Details on mating procedure:

not applicable - reproductive organs of a 2 years study were examined

Analytical verification of doses or concentrations:

yes

Duration of treatment / exposure:

Exposure period: 105 w

Frequency of treatment:

daily

Details on study schedule:

not applicable - reproductive organs of a 2 years study were examined

Remarks:

Doses / Concentrations:
7500, 15000 ppm = ca. 500, 1000 mg/kg bw/d
Basis:

No. of animals per sex per dose:

50 male and 50 female animals

Control animals:

yes, concurrent no treatment

Dose descriptor:

NOAEL

Effect level:

1 000 mg/kg bw/day (nominal)

Sex:

male/female

Reproductive effects observed:

not specified

SURVIVAL: 
reduced from week 75 onwards in dosed male and female rats as well as in  controls:
high-dose males: 36/50, and females: 41/50
low-dose males: 44/50, and females: 42/50
control males: 14/20, and females: 17/20
MEAN BODYWEIGHTS (no data given):
high dose males lower than controls
high dose females and low dose males and females comparable with controls
CLINICAL SIGNS:
dosed groups: low incidences: arched back, rough hair coat, ulceration  and corneal opacity (no further details given)
PATHOLOGICAL EXAMINATION:
by inspection: no difference between the dosed and control groups

Nonneoplastic lesions on reproductive organs:
Organ   control (20)     low dose (50)      high dose (50) 

Males:

preputial gland
 cyst              0/20          1/50 (2%)       0/50 
prostate
 calculus          0/20          0/48            2/45 (4%)
 inflammation, suppurative
                   0/20          2/48 (4%)       1/45 (2%)
 abscess           0/20          0/48            1/45 (2%)
 Inflammation, chronic
                   1/20 (5%)     0/48            0/45 
 inflammation, chronic suppurative
                   1/20 (5%)     0/48            0/45 
 fibrosis          0             1/48 (2%)       0/45
 hyperblasia, focal1/20 (5%)     0/48            0/45
seminal vesicle
 inflammation, suppurative
                   1/20 (5%)     0/50            0/50
testis
 hemorrhage        0/20          0/50            1/50 (2%)
 infarct           0/20          1/50 (2%)       0/50
 atrophy           0/20          3/50 (6%)       2/50 (4%)
epididymis
 inflammation, chronic
                   0/20          0/50           1/50 (2%)
mammary gland
 dilatation/ducts  5/20 (25%)    12/50 (24%)    12/50 (24%)


Females:
mammary gland          20            50          50
  dilatation/ducts     13 (65%)      33 (66%)    24 (48%)
  galactccele           1 (5%)        4 (8%)      1 (2%)
  inflammation, granulomatous 0       1 (2%)     0          
  fibrosis              0             0           1 (2%)
  hyperplasia, Nos      0             0           1 (2%)
  hyperplasia, focal    1 (5%)        0           0
  hyperplasia, cystic   0             0           1 (2%)

uterus                 19            47          50
  hematoma              0             0           1 (2%)
  dilatation, nos       0             1 (2%)      0
      necrosis, nos     1 (5%)        0           0

uterus/endometrium     19            47           50
  dilatation, nos       0             1 (2%)       1 (2%)
  cysti, nos            0             1 (2%)       0
  hyperplasia, epithelial             1 (2%)       0

endothelial gland      19            47           50
  dilatation, nos       3 (16%)       0            0

ovary                  19            47           50
  cyst, nos             1 (5%)        3 (6%)       1 (2%)
  inflamation, chronic  1 (5%)        0            0
  hypoplasia, nos       0             1 (2%)       0


NOAEL: 15000 ppm.

Executive summary:

Groups of 50 rats of each sex were administered phthalic anhydride at one of 2 doses, either 7.500 or 15.000 ppm (ca. 500, 1000 mg/kg bw/d) for 105 weeks. Matched controls consisted of 20 untreated rats of each sex

At the end all animals were killed using CO2 inhalation and necropsied; gross and microscopic examination of: all major organs, including reproductive organs; in male rats preputial gland, prostate, seminal vesicle, testis and epididymis, and the mammary gland; in female rats mammary gland, uterus, endothelial gland, and ovary.

The NOAEL = 1000 mg/kg bw/day (rats, m+f), the pathological examination revealed no difference between the dosed and control groups

reference: Huff, 1984; Kluwe, 1986; NCI, 1979

Effect on fertility: via oral route

Endpoint conclusion:

no adverse effect observed

Additional information

Reproductive toxicity:

There is no study that investigates fertility for PA available.

As confirmed by literature histopathological examinations in repeated dose toxicity are of high value and high sensitivity for evaluation of reproductive toxicity.

In a subacute repeated dose oral toxicity study in male Wistar rats the test animals were given a powder diet containing phthalic acid (PA) at a level of 0.5 or 5% for 34 to 36 days, respectively. No histopathologic effect or decrease in testicle weight could be observed (Murakami, 1986).

Additionally in an insufficient documented, oral repeated dose toxicity study in young male 3 -4 weeks old (70 -100g) albino rats of the Sprague-Dawley strain for 4 days, the treatment did not affect the testicular tissues of rats (Cater, 1977).

In a subacute oral toxicity study in male Wistar rats the test animals were fed diets containing 2% of PA for 1 week. Absolute and relative testicular weights were not decreased compared to control (Oishi, 1980).

In addition two-year chronic feeding studies in rats and mice revealed no evidence of toxicity to reproductive organs was observed, as no treatment-related changes were observed for any reproductive organ investigated during macroscopic and microscopic examination, i.e. preputial gland, prostate, seminal vesicle, testis and epididymis, mammary gland in male rats, and  mammary gland, uterus, endothelial gland, ovary in female rats. The NOAEL for reproduction toxicity in this rat study was determined with 1000 mg/kg bw/day (time-weighted average) (NCI, 1979).

A testing proposal for an Extended One Generation Study (OECD TG 443) is included based on read-across with phthalic anhydride. Phthalic anhydride rapidly hydrolyses in contact with water to phthalic acid.

As confirmed by recent literature (Mangelsdorf et al 2003, Ulbrich & Palmer 1995, Janer et al 2007a, Dent 2007, Sanbuissho et al. 2009)* in rodents histopathological examinations in repeated dose toxicity studies of reproductive tissues are of high value and high sensitivity for evaluation of reproductive toxicity in males and females. Histopathological changes on the reproductive organs in repeated dose toxicity studies are indicative of effects on fertility. With this respect repeated dose toxicity studies should be considered sensitive and sufficient information to evaluate toxicity on fertility if histological examination of the reproductive organs is covered.

Based on the considerations above no further testing is required for the fertility assessment as the test substance has not shown specific effects on reproductive organs in male and female rats and there was no evidence of a specific reproductive toxicity of the test substance in the 2-year oral toxicity studies with phthalic anhydride.

------------------------

* - Mangelsdorf. et al., 2003: Some aspects relating to the evaluation of the effects of chemicals on male fertility. Regulatory toxicology and Pharmacology 36, 69-98

- Ulbrich & Palmer, 1995: Detection of effects on male reproduction – a literature survey. J am. College of Toxicology 14, 293-327

- Janer et al., 2007: A retrospective analysis of the added value of the rat two-generation reproductive toxicity study versus the rat subchronic toxicity study. Reproductive Toxicology 24, 103-113

- Dent, 2007: Strength and limitations of using repeated-dose toxicity studies to predict effects on fertility. Regulatory Toxicology and Pharmacology 48, 241-258

- Sanbuissho et al., 2009: Collaborative work on evaluation of ovarian toxicity by repeated-dose and fertility studies in female rats. J Tox. Sci. 34:Special Issue SP1-SP22

Effects on developmental toxicity

Description of key information

Phthalic acid was investigated in a developmental toxicity feeding study in rats and gave no evidence of embryotoxicity, or fetotoxicty at non-maternally toxic dose levels (up to and including 1.25% in feed = approximately 1021 mg/kg bw/day = NOAEL for maternal toxicity). Significant decreases in the weight of male fetuses and in the numbers of ossified centers of the caudal vertebrae were, however, found in the 5.0 % group, were maternal toxicity was also observed (NOAEL, developmental toxicity: 2.5% in feed = approximately 1763 mg/kg bw/day). Based on the data of phthalic acid, the hydrolysis product of phthalic anhydride, it is concluded that, in the absence of maternal toxicity, phthalic anhydride is not a developmental toxicant.

Link to relevant study records

Reference

Reference 1

Endpoint:

developmental toxicity

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: No OECD guideline or GLP defined.

Qualifier:

no guideline followed

Principles of method if other than guideline:

other: Developmental toxicity study in rats.

GLP compliance:

not specified

Limit test:

no

Species:

rat

Strain:

Wistar Kyoto (WKY)

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Age at study initiation: about 12 weeks
- Weight at study initiation:
- Fasting period before study:
- Diet (e.g. ad libitum): basal diet ad libitum
- Water (e.g. ad libitum): tap water ad libitum

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 24 +- 1°C
- Humidity (%): 55 +-5%
- Air changes (per hr): air-conditioned room
- Photoperiod (hrs dark / hrs light): 12/12

Route of administration:

oral: feed

Vehicle:

other: diet

Details on exposure:

The pregnant rats were fed a diet containing phthalic acid (PA, 99.5% pure, Aldrich, Miwaukee, WI) at a dose of 1.25, 2.5, or 5.0% ad libitum on day 7 through to day 16 of pregnancy.

Analytical verification of doses or concentrations:

not specified

Details on analytical verification of doses or concentrations:

The diet containing PA was prepared fresh weekly. A predetermined amount of PA was weighed and added to a small aliquot of ground basal diet and handblended. This premix was then added to a preweighed ground basal diet and blended with mill (Irie Shokai, Tokyo, Japan) for 30 min. The control rats were fed a basal diet only ad libitum.

Details on mating procedure:

Virgin female rats, about 12 weeks old, were mated overnight with male rats. The day when sperm were detected in the vaginal smear was considered to be day 0 of pregnancy. The pregnant rats were distributed on a random basis into four groups of 11 pregnant rats each housed individually.

Duration of treatment / exposure:

The pregnant rats were fed a diet ad libitum on day 7 through to day 16 of pregnancy.

Frequency of treatment:

continuous via food

Duration of test:

The pregnant rats were sacrified on day 20 of pregnancy.

Dose / conc.:

1.25 other: % in diet

Remarks:

daily test material intake determined with 1021 +- 52 mg/kg bw/day

Dose / conc.:

2.5 other: % in diet

Remarks:

daily test material intake determined with 1763 +- 163 mg/kg bw/day

Dose / conc.:

5 other: %

Remarks:

daily test material intake determined with 2981 +- 270 mg/kg bw/day

No. of animals per sex per dose:

11

Control animals:

yes

Details on study design:

The pregnant rats were fed a diet containing PA (99.5% pure, Aldrich, Milwaukee, WI) at a dose of 1.25, 2.5, or 5.0% ad libitum on day 7 through to day 16 of pregnancy. The administration in the feed was selected because of necessity to expose to large amount of PA and slight solubility of PA in water and oil (Budavari et al.,1996). This method for administration is useful with agents that are to be given in large amounts or are difficult to dissolve in vehicles that would be tolerated in other treatment routes (Wilson, 1965).

Maternal examinations:

CAGE SIDE OBSERVATIONS: Yes
- Time schedule: daily

DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule: daily

BODY WEIGHT: Yes
- Time schedule for examinations: daily

FOOD CONSUMPTION AND COMPOUND INTAKE (if feeding study): Yes
Average daily intake of PA was calculated by the method described by Tyl et al. (1988).

POST-MORTEM EXAMINATIONS: Yes
- Sacrifice on gestation day 20

Ovaries and uterine content:

The peritoneal cavity and uterus were opened and the numbers of live and dead fetuses and resorptions were counted.
The gravid uterus was removed and the rats weighed again. The adjusted weight gain, i.e. maternal weight gain throughout pregnancy corrected for gravid uterine weight, was calculated.

Fetal examinations:

The live fetuses removed from the uterus were sexed, weighed and inspected for external malformations and malformations within the oral cavity. Approximately two-thirds of live fetuses in each litter, randomly selected, were fixed in 99% ethanol, stained alizarin red S (Kawamura et al., 1990) and examined for skeletal malformations. The remaining live fetuses in each litter were fixed in Bouin’s solution and examined for internal malformations using the free-hand razor blade sectioning method of Wilson (1965).

Statistics:

Statistical analysis of the offspring data was carried out using the litter as a unit. Analysis of variance and Dunnett’s multiple comparison test, Kruskal–Wallis test and Mann–Whitney test or Fisher’s exact test were used as appropriate. The 0.05 level of probability was used as the criterion for significance.

Clinical signs:

no effects observed

Description (incidence and severity):

see Table 1

Mortality:

no mortality observed

Description (incidence):

see Table 1

Body weight and weight changes:

effects observed, treatment-related

Description (incidence and severity):

see Table 1: The maternal body weight gain on days 7–16 in the 2.5 and 5.0% groups and the adjusted weight gain, which indicates the net weight gain of maternal rats, in the 5.0% group were significantly lower than those in the control group. The maternal body weight gain on days 16–20 in the 5.0% group was significantly higher than that in the control group.

Food consumption and compound intake (if feeding study):

effects observed, treatment-related

Description (incidence and severity):

see Table 1: A significantly decreased food consumption on days 7–16 in the 2.5 and 5.0% groups and a significantly increased food consumption on days 16–20 in the 1.25, 2.5 and 5.0% groups were found. The average daily intakes of PA were 1021 mg/kg for the 1.25% group, 1763 mg/kg for the 2.5% group, and 2981 mg/kg for the 5.0% group.

Description (incidence and severity):

The reproductive findings in rats given dietary phthalic acid (PA) on day 7 through day 16 of pregnancy are shown in Table 2. No significant differences between the PA-treated groups and the control group were detected in the numbers of corpora lutea per litter, implantations per litter, resorptions and dead fetuses per litter and live fetuses per litter, incidence of postimplantation loss per litter, and sex ration of live fetuses.

Dose descriptor:

NOAEL

Effect level:

ca. 1 021 mg/kg bw/day (nominal)

Based on:

test mat.

Basis for effect level:

other: maternal toxicity

Dose descriptor:

NOAEL

Effect level:

ca. 1 763 mg/kg bw/day (nominal)

Based on:

test mat.

Basis for effect level:

other: developmental toxicity

Fetal body weight changes:

effects observed, treatment-related

Description (incidence and severity):

see Table 2: The weight of male fetuses in the 5.0% group was significantly lighter than that in the control group, although no significantly decreased weight of female fetuses was found in any PA-treated groups.

External malformations:

no effects observed

Skeletal malformations:

no effects observed

Description (incidence and severity):

see Table 3: A few types of skeletal variations in the vertebrae and sternebrae were observed in the control and PA-treated groups.

Visceral malformations:

no effects observed

Dose descriptor:

NOAEL

Effect level:

1 763 mg/kg bw/day

Based on:

test mat.

Sex:

male/female

Remarks on result:

other: body weight male fetuses

Abnormalities:

not specified

Developmental effects observed:

not specified

Table 1: Maternal findings in rats given dietary PA on days 7 -16 of pregnancy:

	PA (%)
	0 (control)	1.25	2.5	5.0
No. of pregnant rats	11	11	11	11
No. of dead pregnant rats	0	0	0	0
Initial body weight (g)	242+10	243+16	243+12	244+16
Body weight gain during pregnancy^a)
Days 0 -7	24+6	26+10	31+6	27+7
Days 7 -16	49+8	54+8	40+5*	20+12**
Days 16 -20	41+9	40+8	47+11	57+16**
adjusted weight gain^b)	50+11	47+10	42+10	30+12**
Food consumption during pregnancy (g)^a)
Days 0 -7	138+8	140+15	145+13	138+8
Days 7 -16	198+11	197+10	173+17**	145+13**
Days 16 -20	88+10	98+4**	101+6**	120+7**
Daily intake of PA (mg/kg)^a,c)	0	1021+52	1763+163	2981+270

^a)Values are given as mean+S.D:

^b)Adjusted weight gain refers to maternal weight gain excluding the gravid uterus.

^c)[Food consumotion on days 7 -16/9)x%PA]/body weight on day 7.

*,**Significantly different from the control, P<0.05 and P<0.0.1, respectively.

Table 2: Reproductive findings in rats given dietary PA on days 7 -16 of pregnancy:

	PA (%)
	0 (control)	1.25	2.5	5.0
No. of litters	11	11	11	11
No. of corpora lutea per litter^a)	14.3 +1.3	15.3 +1.6	15.7 +2.3	15.7 +1.5
No. of implantations per litter^a)	13.1 +2.1	14.0 +1.7	14.3 +3.3	13.8 +3.4
No. of litters totally resorbed	0	0	0	0
No. of resorbtions and dead fetuses per litter^a)	1.6 +1.6	1.3 +1.1	0.9 +1.0	1.3 +1.4
% Postimplantation loss per litter^b)	14.2	9.3	5.8	8.7
No. of live fetuses per litter^a)	11.5 +3.0	12.7 +2.2	13.4 +3.0	12.5 +3.4
Sex ratio of live fetuses (male/female)	60/66	61/79	83/64	62/76
Body weight of live fetuses (g)^a)
Male	4.19 +0.13	4.15 +0.07	4.20 +0.18	4.03 +0.18*
Female	3.92 +0.16	3.95 +0.13	3.92 +0.15	3.82 +0.14

^a) values are given as mean + S.D.

^b) (No. of resorbtions and dead fetuses/no. of implantations)x100.

* Significantly different from the control, P<0.05.

Table 3: Morphological findings in fetuses of rats given dietary PA on days 7 -16 of pregnancy:

	PA (%)
	0 (control)	1.25	2.5	5.0
external examination
No. of fetuses (litters) examined	126 (11)	140 (11)	147 (11)	138 (11)
No. of fetuses (litters) with malformations	0	0	0	0
Skeletal examination
No. of fetuses (litters) examined	84 (11)	94 (11)	97 (11)	92 (11)
No. of fetuses (litters) with malformations	0	0	0	0
No. of fetuses (litters) with variations	4 (3)	5 (4)	4 (3)	10 (6)
No. of fetuses (litters) with:
Splitting of thoracic vertebral bodies	1 (1)	0	0	0
Asymetric of sternebrae	3 (3)	4 (3)	4 (3)	7 (6)
Splitting of sternebrae	0	1 (1)	0	5 (3)
Degree of ossification
No. of ossification centers of caudal vertebrae^a)	5.5 +0.3	5.3 +0.3	5.4 +0.3	5.1 +0.2*
No. of sternebrae^a)	5.9 +0.1	6.0 +0	6.0 +0.1	5.9 +0.1
Internal examination
No. of fetuses (litters) examined	42 (11)	46 (11)	50 (11)	46 (11)
No. of fetuses (litters) with malformations	0	0	0	0

^a) Values are given as mean +S.D.

* Significantly different from the control, P<0.01.

Executive summary:

The developmental toxicity of phthalic acid was investigated in a developmental toxicity study. Groups of eleven pregnant Wistar rats were fed a diet containing phthalic acid at a dose of 0, 1.25, 2.5, or 5.0 % ad libitum on GD 7 - GD 16 ( average daily intake: 0, 1021, 1763, 2981 mg/kg bw/day). The pregnant rats were observed daily for evidence of clinical signs of toxicity, maternal body weight and food consumption, and were sacrificed on day 20 of pregnancy. The peritoneal cavity and uterus were opened and the numbers of live and dead fetuses and resorptions were counted. The gravid uterus was removed and the rats weighed again. The adjusted weight gain, i.e. maternal weight gain throughout pregnancy corrected for gravid uterine weight, was calculated. The live fetuses removed from the uterus were sexed, weighed and inspected for external malformations and malformations within the oral cavity. Approximately two-thirds of live fetuses in each litter, randomly selected, were stained with alizarin red S and examined for skeletal malformations. The remaining live fetuses in each litter were fixed in Bouin¿s solution and examined for internal malformations. Maternal toxicity occurred in the 2.5 and 5.0 % groups as demonstrated by decreases in the adjusted maternal bodyweight gain (maternal bw gain excluding the gravid uterus; 30, 42, or 50 g for the 5, 2.5, or control group, respectively) during the administration period. No significant changes in maternal parameters were found in the 1.25 % group (adjusted body weight gain 47 g). No deaths or clinical signs of toxicity were noted in any group. No significant changes induced by phthalic acid were detected in the incidence of postimplantation loss, number and sex ratio of live fetuses. No fetuses with external, skeletal and internal malformations were found in any group. Significant decreases in the weight of male fetuses and decreased numbers of ossified centers of the caudal vertebrae were found only in the 5.0 % group, where significant maternal toxicity also was observed. Morphological examinations of fetuses revealed no evidence of developmental toxicity (NOAEL, maternal toxicity: 1.25 % in feed = 1021 mg/kg bw/day; NOAEL, developmental toxicity: 2.5 % in feed = 1763 mg/kg bw/day).

Reference 2

Endpoint:

developmental toxicity

Remarks:

second species

Type of information:

experimental study planned (based on read-across)

Remarks:

An OECD TG 414 study in the rabbit by the oral route of exposure is proposed as per REACH Annex X, Section 8.7.2 for phthalic anhydride (CAS-No. 85-44-9). For justification see RAAF document attached to this registration dossier.

Study period:

An OECD TG 414 study in the rabbit by the oral route of exposure is proposed as per REACH Annex X, Section 8.7.2 for phthalic anhydride (CAS-No. 85-44-9). The test period will be established once the ECHA approves this Testing Proposal.

Justification for type of information:

TESTING PROPOSAL ON VERTEBRATE ANIMALS
Prenatal developmental toxicity study – second species: rabbit (OECD TG 414) with the registered substance.

NON-CONFIDENTIAL NAME OF SUBSTANCE:
- Name of the substance on which testing is proposed to be carried out:
phthalic anhydride (CAS 85-44-9)

- Name of the substance for which the testing proposal will be used [if different from tested substance:
Phthalic anhydride will be used if technically feasible. Since the number of vehicles that can be used in rabbit studies is limited compared to e.g. rat studies, in case no stability can be achieved in any rabbit compatible vehicle, the use of the hydrolysis product phthalic acid (CAS 88-99-3) will be considered after appropriate documentation.

CONSIDERATIONS THAT THE GENERAL ADAPTATION POSSIBILITIES OF ANNEX XI OF THE REACH REGULATION ARE NOT ADEQUATE TO GENERATE THE NECESSARY INFORMATION [please address all points below]:
- Available GLP studies:

No GLP studies for the substance are available to cover the endpoint ‘developmental toxicity, second species’. The available repeated dose toxicity studies were performed before 1979 and the GLP status is thus not given.

- Available non-GLP studies:
Studies with relevance for developmental toxicity:
No valid developmental toxicity/teratogenicity study with phthalic anhydride is available. However, phthalic anhydride is known to undergo rapid hydrolysis to phthalic acid on contact with water. The kinetic of the hydrolysis of phthalic anhydride was shown to be 30.5 seconds at pH 7.24 and 25 °C, 52.5 seconds at pH 6.8 and 75 seconds at pH 0 - 6 and 25°C (range 66.6 to 79.5 seconds) (Andres, 2001). It is likely that a similar reaction will occur in biological systems, which is supported by the presence of unconjugated phthalic acid in the urine of workers occupationally exposed to phthalic anhydride (Pfaeffli, 1986). Thus, a read-across with data obtained for the acid is considered adequate.
Phthalic acid was investigated in a prenatal developmental toxicity feeding study in rats (Ema, 1997). The GLP status of this study is not given in the publication. The dosing period was from gestation days 7 to 16, followed by sacrifice on gestation day 20. The average daily phthalic acid intake was calculated with 1021, 1763, and 2981 mg/kg bw/day. Maternal toxicity occurred in the two highest dose groups as demonstrated by decreases in the adjusted maternal bodyweight gain (maternal bw gain excluding the gravid uterus minus 16% in the mid dose group and minus 40% in the high dose group compared to control). No deaths or clinical signs of toxicity were noted in any group. No significant changes induced by phthalic acid were detected in the incidence of post-implantation loss, number and sex ratio of live fetuses. No fetuses with external, skeletal and internal malformations were found in any group. Significant decreases in the weight of male fetuses and decreased numbers of ossified centers of the caudal vertebrae were found only in the 5.0 % group, where significant maternal toxicity was observed. The NOAEL maternal toxicity was 1021 mg/kg bw/day and the NOAEL developmental toxicity was 1763 mg/kg bw/day in this study.
Based on the data of phthalic acid, the hydrolysis product of phthalic anhydride, it can be concluded that, in the absence of maternal toxicity, phthalic anhydride is not a developmental toxicant.

No reliable developmental toxicity studies on a second species (e.g. rabbit) are available, neither for phthalic anhydride nor for phthalic acid.
Two chronic repeated dose toxicity studies are available in which rats or mice were fed a diet containing phthalic anhydride. In these studies phthalic anhydride has been shown to have low repeated dose toxicity by the oral route. The dosing periods comprised 105 weeks (NCI, 1979). No evidence of toxicity to reproductive organs was observed in these studies, as no treatment-related changes were observed for any reproductive organ investigated during macroscopic and microscopic examination, i.e. preputial gland, prostate, seminal vesicle, testis and epididymis, mammary gland in male rats, and mammary gland, uterus, endothelial gland, ovary in female rats. The NOAEL for reproduction toxicity in this rat study was determined with 1000 mg/kg bw/day (time-weighted average). In the mouse study histopathology of reproductive relevant organs were performed on epididymis in male mice and uterus and ovary of female mice and showed no treatment related changes. The NOAELs for reproduction toxicity in this study was 3430 mg/kg bw/day for female mice and 4670 mg/kg bw/day for male mice.

- historical human data
No human data are available to cover the endpoint developmental toxicity - second species.

- (Q)SAR
no reliable data available; there is no QSAR model available which is accepted by ECHA for the endpoint reproductive toxicity – developmental toxicity.
According to DART (Developmental And Reproduction Toxicity) scheme profiler of the QSAR Toolbox 4.4 query of June 2020 phthalic anhydride and phthalic acid are not associated with chemical structures known to have DART, thus, phthalic anhydride and phthalic anhydride are not foreseen as developmental or reproductive toxicants.
The toxic hazard classification by Cramer (and Cramer extended) obtained in the QSAR Toolbox is predicted with high hazard for phthalic anhydride based on the reactive aldehyde group (Cramer class III) and low hazard for phthalic acid after hydrolysis (Cramer class I).

- In vitro methods
no reliable data available; there are no in vitro methods available which are accepted by ECHA for the endpoint reproductive toxicity – developmental toxicity

- Weight of evidence
No specific studies on developmental toxicity are available for phthalic anhydride.
Phthalic acid, the hydrolysis product of phthalic anhydride, was tested in a developmental toxicity feeding study in rats in oral doses of up to 2981 mg/kg bw/day. Maternal toxicity occurred in the two highest dose groups of 2.5 and 5% phthalic acid in food. Significant decreases in the weight of male fetuses and decreased numbers of ossified centers of the caudal vertebrae were found only in the 5% group, where significant maternal toxicity was observed. Therefore, in this study the NOAEL for developmental toxicity was 2.5% in feed (= approximately 1763 mg/kg bw/day) and the NOAEL for maternal toxicity was 1.25% in feed (= approximately 1021 mg/kg bw/day). Based on the data of phthalic acid, the hydrolysis product of phthalic anhydride, it can be concluded that, in the absence of maternal toxicity, phthalic anhydride is not a developmental toxicant.
The OECD QSAR Toolbox version 4.4 does not identify any chemical structures that point to a reproductive toxicity potential (DART profiler) for phthalic anhydride and phthalic acid.

- Grouping and read-across
There are no read-across compounds with adequate data bases for reproductive toxicity available to cover the endpoint developmental toxicity – second species. The developmental toxicity study available for phthalic acid was performed on rats (Ema, 1997).
A hydrolysis study has shown that phthalic anhydride rapidly hydrolyses to phthalic acid (CAS-No. 88-99-3) under aqueous conditions. In the presence of water phthalic anhydride hydrolyses rapidly forming phthalic acid. The kinetic of the hydrolysis of phthalic anhydride was studied to be 30.5 seconds at pH 7.24 and 25 °C. At pH 8.9 the half-life of phthalic anhydride in water dropped to 2.4 seconds (Andres et al., 2001). Thus, phthalic anhydride would be rapidly hydrolyzed to phthalic acid in the gastrointestinal tract after ingestion and thus, phthalic acid can be considered as the relevant toxicity driver in animals and humans after oral uptake. A read-across of toxicological data from phthalic anhydride to the acid and vice versa is thus considered adequate. (see RAAF Document attached to the dossier)
No prenatal developmental toxicity study in a second species (e.g. rabbit) is available for phthalic acid, therefore, phthalic acid cannot be used as source for data in a read-across approach. However, the results obtained in the prenatal developmental toxicity study in a second species (e.g. rabbit) with phthalic anhydride are intended to be included in the dossier of phthalic acid. The proposed prenatal developmental toxicity study in a second species (e.g. rabbit) with phthalic anhydride will be used to fill the data gap for developmental toxicity – second species - of phthalic acid in a read-across approach as source. Thus, the proposed prenatal developmental toxicity study in a second species (rabbit) with phthalic anhydride will not only serve for the assessment of phthalic anhydride but also, via read-across, for the assessment of phthalic acid.

- Substance-tailored exposure driven testing [if applicable]
not applicable.

- Approaches in addition to above [if applicable]
not applicable.

- Other reasons [if applicable]
not applicable.

CONSIDERATIONS THAT THE SPECIFIC ADAPTATION POSSIBILITIES OF ANNEXES VI TO X (AND COLUMN 2 THEREOF) OF THE REACH REGULATION ARE NOT ADEQUATE TO GENERATE THE NECESSARY INFORMATION:
There is no prenatal developmental toxicity study in a second species (e.g. rabbit) study for phthalic anhydride available and the adaptation options as defined in Annexes VI to X (and column 2 thereof) are, on a formal basis, not applicable for this substance and this endpoint.
Therefore, as none of the general and specific adaption rules in column 2 provide possibilities for omitting the testing and testing is technically feasible, there is no other option to formally fulfil the requirements than to conduct the prenatal developmental toxicity study in a second species (rabbit) with phthalic anhydride to fulfill the requirements.

FURTHER INFORMATION ON TESTING PROPOSAL IN ADDITION TO INFORMATION PROVIDED IN THE MATERIALS AND METHODS SECTION:
- Details on study design / methodology proposed [if relevant]
Study to follow OECD TG 414, species: rabbit, route of administration: oral

For further information see attached document:
Justification for a read-across between phthalic acid and phthalic anhydride

Guideline:

OECD Guideline 414 (Prenatal Developmental Toxicity Study)

Species:

rabbit

Route of administration:

other: oral, most appropriate application route

Effect on developmental toxicity: via oral route

Endpoint conclusion:

adverse effect observed

Additional information

Developmental Toxicity:

The developmental toxicity of phthalic acid was investigated in a developmental toxicity study. Groups of eleven pregnant Wistar rats were fed a diet containing phthalic acid at a dose of 0, 1.25, 2.5, or 5.0 % ad libitum on GD 7 - GD 16 ( average daily intake: 0, 1021, 1763, 2981 mg/kg bw/day). The pregnant rats were observed daily for evidence of clinical signs of toxicity, maternal body weight and food consumption, and were sacrificed on day 20 of pregnancy. The peritoneal cavity and uterus were opened and the numbers of live and dead fetuses and resorptions were counted. The gravid uterus was removed and the rats weighed again. The adjusted weight gain, i.e. maternal weight gain throughout pregnancy corrected for gravid uterine weight, was calculated. The live fetuses removed from the uterus were sexed, weighed and inspected for external malformations and malformations within the oral cavity. Approximately two-thirds of live fetuses in each litter, randomly selected, were stained with alizarin red S and examined for skeletal malformations. The remaining live fetuses in each litter were fixed in Bouin¿s solution and examined for internal malformations. Maternal toxicity occurred in the 2.5 and 5.0 % groups as demonstrated by decreases in the adjusted maternal bodyweight gain (maternal bw gain excluding the gravid uterus; 30, 42, or 50 g for the 5, 2.5, or control group, respectively) during the administration period. No significant changes in maternal parameters were found in the 1.25 % group (adjusted body weight gain 47 g). No deaths or clinical signs of toxicity were noted in any group. No significant changes induced by phthalic acid were detected in the incidence of postimplantation loss, number and sex ratio of live fetuses. No fetuses with external, skeletal and internal malformations were found in any group. Significant decreases in the weight of male fetuses and decreased numbers of ossified centers of the caudal vertebrae were found only in the 5.0 % group, where significant maternal toxicity also was observed. Morphological examinations of fetuses revealed no evidence of developmental toxicity (NOAEL, maternal toxicity: 1.25 % in feed = 1021 mg/kg bw/day; NOAEL, developmental toxicity: 2.5 % in feed = 1763 mg/kg bw/day) (Ema, 1997).

A testing proposal for a Prenatal Developmental Toxicity Study in rabbits (OECD TG 414) is included based on read-across with phthalic anhydride. Phthalic anhydride rapidly hydrolyses in contact with water to phthalic acid.

Justification for classification or non-classification

Based on the available study a non-classification for toxicity to reproduction is justified.