Phosphoric acid, mono- and di-C11-14 (linear and branched) alkyl esters

Developmental toxicity / teratogenicity

Administrative data

Endpoint:

developmental toxicity

Type of information:

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

Adequacy of study:

key study

Study period:

1994-01-07 to 1994-11-09

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: see 'Remark'

Remarks:

GLP - Guideline study, tested with the source substance Phosphoric acid, C9-15 branched and linear alkyl esters, potassium salts. In accordance to the ECHA guidance document “Practical guide 6: How to report read-across and categories (March 2010)”, the reliability was changed from RL1 to RL2 to reflect the fact that this study was conducted on a read-across substance.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1994

Report date:

1994

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 414 (Prenatal Developmental Toxicity Study)

Deviations:

yes

Remarks:

: Analytical verification (homogeneity, stability and concentration) of the test material formulations was not performed.

GLP compliance:

yes (incl. QA statement)

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

Phosphoric acid, C9-15 branched and linear alkyl esters, potassium salts

IUPAC Name:

Phosphoric acid, C9-15 branched and linear alkyl esters, potassium salts

Constituent 2

Reference substance name:

97468-13-8 (Phosphoric acid, C9-11 branched and linear alkyl esters, potassium salts) and 91844-80-3 (Phosphoric acid, C13-15 branched and linear alkyl ester, potassium salts); 50/50

IUPAC Name:

97468-13-8 (Phosphoric acid, C9-11 branched and linear alkyl esters, potassium salts) and 91844-80-3 (Phosphoric acid, C13-15 branched and linear alkyl ester, potassium salts); 50/50

Details on test material:

- Name of test material (as cited in study report): Alkyl Potassium Phosphate
- Analytical purity: 36.1% potassium salt

Test animals

Species:

rat

Strain:

other: Sprague-Dawley Crl:CD® BR rats

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Age at study initiation (females): 13 weeks
- Weight at study initiation (females): minimum 220 g (215 to 291 g on day 0 of gestation)
- Fasting period before study: no
- Housing: wire-mesh cage
- Diet (e.g. ad libitum): Purina Certified Rodent Chow #5002, ad libitum
- Water (e.g. ad libitum): tap water, ad libitum
- Acclimation period: 19 days

ENVIRONMENTAL CONDITIONS
- Temperature (°F): 67°F to 74°F
- Humidity (%): 28% to 58%
- Air changes (per hr): 10
- Photoperiod (hrs dark / hrs light): 12/12

IN-LIFE DATES: From: To: 1994-01-11 to 1994-02-4

Administration / exposure

Route of administration:

oral: gavage

Vehicle:

water

Remarks:

deionized water, prepared on site

Details on exposure:

PREPARATION OF DOSING SOLUTIONS:
An appropriate amount of test material, alkyl potassium phosphate, was weighed for each group into a tared precalibrated storage container. A sufficient amount of vehicle, deionized water, was added to bring the suspension to the appropriate volume. The preparations were stirred using a magnetic stir bar continuously during the dosing procedure. All dosing preparations were visually inspected by the Study Director on the first day of administration and appeared to be homogeneous and acceptable for administration. Preparations for all dose groups were made daily and were stored at room temperature. Analytical chemistry determinations to establish homogeneity, stability and concentration were not required by the protocol and were not conducted.

Analytical verification of doses or concentrations:

no

Details on analytical verification of doses or concentrations:

Dosage calculations were not adjusted for puritiy. The bulk material was 36.1% pure (as the potassium salt).

Details on mating procedure:

- Impregnation procedure: cohabitation
- If cohoused:
- M/F ratio per cage: 1 to 1
- Length of cohabitation: not given - Each mating pair was examined daily. Positive evidence of mating was confirmed by the presence of a copulatory plug or the presence of sperm in a vaginal smear. Each mating pair was examined daily. The day on which evidence of mating was identified was termed day 0 of gestation and the animals were separated.
- Verification of same strain and source of both sexes: yes
- Resident males were from the same strain and source.
- Resident males were untreated, sexually mature rats utilized exclusively for breeding
- Proof of pregnancy: vaginal plug or sperm in vaginal smear referred to as day 0 of pregnancy
- Any other deviations from standard protocol: After mating, female rats were removed and allocated to the test groups.

Duration of treatment / exposure:

10 consecutive days initiating on gestation day 6 and continuing up to and including day 15 of gestation

Frequency of treatment:

once daily

Duration of test:

Females were sacrificed on day 21 post coitum.

Doses / concentrations

Doses / concentrations 1

Remarks:

Doses / Concentrations:
0 mg/kg bw/day (vehicle control)
Basis:
actual ingested
active ingredient

Doses / concentrations 2

Remarks:

Doses / Concentrations:
36.1 mg/kg bw/day
Basis:
actual ingested
active ingredient

Doses / concentrations 3

Remarks:

Doses / Concentrations:
180.5 mg/kg bw/day
Basis:
actual ingested
active ingredient

Doses / concentrations 4

Remarks:

Doses / Concentrations:
361 mg/kg bw/day
Basis:
actual ingested
active ingredient

No. of animals per sex per dose:

25/group.

Control animals:

yes, concurrent vehicle

Details on study design:

- Dose selection rationale: Dosages were based on the results of the dose range-finding sudy
- Rationale for animal assignment (if not random): The first mated female and the appropriate gestation day 0 designation were entered on the form and the female was assigned to group 1, the second mated female was assigned to group 2, and the third to group 3, etc. This process was continued daily until 25 females were placed into each group.
- Other: International guidelines recognize the efficacy of oral administration.

Examinations

Maternal examinations:

CAGE SIDE OBSERVATIONS: Yes
- Time schedule: All rats were observed twice daily for moribundity and mortality.
- Cage side observations checked in table [No.?] were included.

DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule: Detailed clinical observations were recorded individually from days 0 through 20 of gestation (prior to compound administration during the dosing period). On the first day of test material administration for this study, animals were observed for signs of toxicity approximately one, two and four hours following dosing. Few post-dosing clinical signs were observed two and four hours following dosing; therefore, only a one-hour post-dosing observation was scheduled for the remainder of the test material administration period.

BODY WEIGHT: Yes
- Time schedule for examinations: Individual maternal body weights for all females were recorded on gestation days 0, 6-16 and 20.

FOOD CONSUMPTION AND COMPOUND INTAKE (if feeding study): Yes (Individual food consumption was recorded on gestation days 0, 6-16 and 20.)
- Food consumption for each animal determined and mean daily diet consumption calculated as g food/kg body weight/day: Yes (Food intake was reported as g/animal/day and g/kg/day for each corresponding body weight change interval.)
- Compound intake calculated as time-weighted averages from the consumption and body weight gain data: No (Compound was administered via gavage)

WATER CONSUMPTION AND COMPOUND INTAKE (if drinking water study): No
- Time schedule for examinations: N/A

POST-MORTEM EXAMINATIONS: Yes
- Sacrifice on gestation day # 20: animals were euthanized by carbon dioxide inhalation. Fetuses were removed by Caesarean section.
- Organs examined: Emphasis on the uterus and its contents, number and position of the fetuses in the uterus, early and late resorptions and the total number of implantation sites.
- Specimens of abnormal tissue were fixed in 10% neutral buffered formalin.

OTHER: Uteri with no macroscopic evidence of nidation were excised, opened and subsequently placed in 10% ammonium sulfide for detection of early implantation loss.

Ovaries and uterine content:

The ovaries and uterine content was examined after termination: Yes
Examinations included:
- Gravid uterus weight: Yes
- Number of corpora lutea: Yes
- Number of implantations: Yes
- Number of early resorptions: Yes
- Number of late resorptions: Yes
- Other:

Fetal examinations:

- External examinations: Yes: all per litter;
sex, detailed external examination of each fetus included eyes, palate and external orifices and each fmding was recorded.
crown-rump measurements and any external malformations were recorded for late resorptions
- Soft tissue examinations: Yes: all per litter
- each fetus was examined viscerally by the Wilson sectioning technique; sections containing malformations were preserved in 10% neutral buffered formalin, all remaining serial sections were discarded
-examination of kidneys, grading for renal papillae development

- Skeletal examinations: Yes: all per litter
- Head examinations: Yes: all per litter; The heads from all of the fetuses were examined by a mid-coronal slice.

Statistics:

All analyses were conducted using two-tailed tests for a minimum significance level of 5% comparing each treated group to the vehicle control group.
Chi-square test with Yates correction factor - fetal sex ratios
Fisher's Exact test - malformations and variations
Mann-Whitney U-test - early and late resorptions, dead fetuses, post-implantation losses, mean litter proportions of malformations and variations
One-way ANOVA with Dunnett's test - corpora lutea, total implantations, viable fetuses, fetal body weights, maternal body weights, weight changes, gravid
uterine weights and maternal food consumption
Kruskal-Wallis test - litter proportions of intrauterine data (considering the litter, rather than the fetus, as the experimental unit)

Indices:

fetal sex ratios
malformations and variations
early and late resorptions
dead fetuses
post-implantation losses
mean litter proportions of malformations and variations
corpora lutea
total implantations
viable fetuses
fetal body weights
maternal body weights
weight changes
gravid uterine weights
maternal food consumption
litter proportions of intrauterine data (considering the litter, rather than the fetus, as the experimental unit)

Historical control data:

yes (for embryotoxic effects)

Results and discussion

Results: maternal animals

Maternal developmental toxicity

Details on maternal toxic effects:

Maternal toxic effects:no effects. Remark: no treatment related effects

Details on maternal toxic effects:
CUNlCAL OBSERVATIONS AND SURYIVAL No mortality. The predominant clinical sign in the treated groups was rales, which generally did not persist past one hour following dosing. In the 180.5 and 361 mg/kg/day groups, rales were observed in 17 and 16 animals, respectively, on one to five occasions one hour following dosing. Other clinical signs in the treated groups occurred infrequently (generally in single animals) and/or were observed similarly in the control group. BODY WEIGHTS AND GRAYID UTERINE WEIGHTS Mean gravid uterine weight, net body weight and net body weight gain in the highest dose group were slightly lower than the control group values. None of the differences were statistieally significant. Mean body weights, body weight gains, gravid uterine weights, net body weights and net body weight gains in the 36.1 and 180.5 mg/kg/day groups were comparable to the control group values. FOOD CONSUMPTION Food consumption, evaluated as g/animal/day and g/kg/day, in the 36.1, 180.5 and 361 mg (a.i.)/kg/day groups was unaffected by compound administration. The only statistically significant difference (p <0.01) between the control and treated groups was a slightly lower g/animall/day food consumption value in the 361 mg/kg/day group during the post-treatment period (gestation days 16-20). The difference between the control and high dose groups was slight (2 g/animal/day) and no relationship to treatment was apparent. NECROPSY DATA At the scheduled necropsy, no internal findings related to compound administration were observed at any dose level. GESTATION DAY 20 LAPAROHYSTERECTOMY DATA Intrauterine growth and survival were unaffected by compound administration at any dose level. Postimplantation losses in the treated groups were comparable to the control group value. The mean numbers of viable fetuses in the treated groups were also comparable to the control group value with one exception. The mean number of viable fetuses in the 361 mg/kg/day group (12.3 fetuses/dam) was slightly lower than the control group value (13.9 fetuses/dam). The low number of viable fetuses in the high dose group was due to lower mean numbers of corpora lutea and implantation sites in the 361 mg/kg/day group (15.9 corpora lutea/dam and 13.1 implantation sites/dam) than in the control group (17.5 corpora lutea/dam and 14.7 implantation sites/dam). As the numbers of corpora lutea and implantation sites are inherently determined prior to the initiation of dosing, no relationship to treatment was evident. The mean numbers of corpora lutea and implantation sites in the 36.1 and 180.5 mg/kg/day groups were comparable to the control group values. Mean fetal body weights and fetal sex ratios in all treated groups were comparable to the control group values. None of the differences between the control and treated groups were statistically significant.

Effect levels (maternal animals)

1

Dose descriptor:

NOEL

Effect level:

36.1 mg/kg bw/day

Based on:

act. ingr.

Basis for effect level:

other: maternal toxicity

2

Dose descriptor:

NOAEL

Effect level:

361 mg/kg bw/day

Based on:

act. ingr.

Basis for effect level:

other: maternal toxicity

3

Dose descriptor:

NOEL

Effect level:

361 mg/kg bw/day

Based on:

act. ingr.

Basis for effect level:

other: developmental toxicity

Results (fetuses)

Details on embryotoxic / teratogenic effects:

Embryotoxic / teratogenic effects:no effects. Remark: no treatment related effects

Details on embryotoxic / teratogenic effects:
The numbers of fetuses (litters) available for fetal morphological examination were 305(22), 266(19), 330(23) and 271(22) in the control, 36.1, 180.5 and 361 mg/kg/day groups, respectively. The number of fetuses (litters) with malformations were 1(1), 1(1), 1(1), 0(0) in these dose groups, respectively. EXTERNAL MALFORMATIONS AND VARIATIONS one fetus in the 180.5 mg/kg/day group had multiple anomalies. These consisted of craniorachischisis, facial cleft, microphthalmia (unilateral) and ablepharia (bilateral). No other external malformations and no external developmental variations were observed at any dose level. VISCERAL MALFORMATIONS AND VARIATIONS One fetus in the control group had an encephalomeningocele (portion of brain and meninges protruded through an opening in the skull). One fetus in the 36.1 mg/kg bw/day group was hydrocephalic. No other soft tissue malformations were observed at any dose level. Soft tissue developmental variations were observed in two control group fetuses. Both fetuses had renal papillae that were not developed and one fetus also had a distended ureter. No other soft tissue developmental variations were noted. SKELETAL MALFORMATIONS AND VARIATIONS One fetus in 180.5 mg/kg/day group had multiple external skeletal malformations and (external: craniorachischisis, facial cleft, unilateral microphthalmia and bilateral ablepharia; skeletal malformations: malformed clavicle and scapula and a vertebral anomaly with an associated rib anomaly). Skeletal developmental variations in all treated groups, such as cervical centrum no. 1 ossified, sternebrae nos. 5 and/or 6 unossified and 14th rudimentary ribs, occurred at a similar frequency in the control group, did not occur in a dose related manner and/or were within the range of historical control data. All other skeletal variants occurred infrequently (generally in single fetuses) or occurred similarly in the control group.

Effect levels (fetuses)

1

Dose descriptor:

NOEL

Effect level:

361 mg/kg bw/day

Based on:

act. ingr.

Basis for effect level:

other: embryotoxicity

2

Dose descriptor:

NOEL

Effect level:

361 mg/kg bw/day

Based on:

act. ingr.

Basis for effect level:

other: fetotoxicity

3

Dose descriptor:

NOEL

Effect level:

361 mg/kg bw/day

Based on:

act. ingr.

Basis for effect level:

other: teratogenicity

Fetal abnormalities

Abnormalities:

not specified

Overall developmental toxicity

Developmental effects observed:

not specified

Any other information on results incl. tables

CLINlCAL OBSERVATIONS AND SURYIVAL

All animals survived to the scheduled necropsy on gestation day 20. The predominant clinical sign in the treated groups was rales. In the 180.5 and 361 mg/kg/day groups, rales were observed in 17 and 16 animals, respectively, on one to five occasions one hour following dosing between gestation days 6 and 15.

Based on findings two and four hours following dosing on the initial day of compound administration, rales generally did not persist past one hour following dosing. Several animals in the 180.5 and 361 mg/kg/day groups (6 and 2, respectively) were also noted to have rales at the daily examinations prior to dosing. Rales were also observed on one occasion in a single 36.1 mg/kg/day group animal (one hour following dosing on gestation day 8). However, the single occurrence of rales at a dose level of 36.1 mg/kg/day was not suggestive of a relationship to compound administration.

Other clinical signs in the treated groups, such as hair loss on various body surfaces, red material around the nose and soft stool, occurred infrequently (generally in single animals) and/or were observed similarly in the control group. No relationship to compound administration was evident.

BODY WEIGHTS AND GRAVID UTERINE WEIGHTS

Mean body weight gains in the 361 mg/kg/day group were comparable to the control group values during the first six days of dosing (gestation days 6-9 and 9-12).

Throughout the remainder of the treatment period (gestation days 12-16), mean body weight gain in this group was slightly reduced when compared to the control group value. The difference was not statistically significant. When the overall treatment period was evaluated (gestation days 6-16), a statistically significant (P<0.05) reduced mean body weight gain occurred in the 361 mg/kg/day group when compared to the control group value. During the post-treatment period (gestation days 16-20), mean body weight gain in the 361 mg/kg/day group continued to be slightly lower than the control group value. The difference was not statistically significant. Mean body weights in the 361 mg/kg/day group were similar to the control group values throughout the study. Mean gravid uterine weight, net body weight and net body weight gain in this group were slightly lower than the control group values. None of the differences were statistically significant. Mean body weights, body weight gains, gravid uterine weights, net body weights and net body weight gains in the 36.1 and 180.5 mg/kg/day groups were comparable to the control group values.

FOOD CONSUMPTION

Food consumption, evaluated as g/animal/day and g/kg/day, in the 36.1, 180.5 and 361 mg/kg/day groups was unaffected by compound administration. The only statistically significant difference (p <0.01) between the control and treated groups was a slightly lower g/animal/day food consumption value in the 361 mg/kg/day group during the post-treatment period (gestation days 16-20). The difference between the control and high dose groups was slight (2 g/animal/day) and no relationship to treatment was apparent.

NECROPSY DATA

At the scheduled necropsy, no internal findings related to compound administration were observed at any dose level. One female in each of the control and 180.5 mg/kg/day groups (nos. 20671 and 20570, respectively) had dilated renal pelves. The 180.5 mg/kg/day group female (no. 20566) also had enlarged placentas at site nos. 7 and 12. Female no. 20656 in the 36.1 mg/kg/day group had reddened cortieo-medullary junctions in the kidneys. Control group female no. 20593 had a thickened urinary bladder containing one white calculus. All other animals were internally normal.

GESTATION DAY 20 LAPAROHYSTERECTOMY DATA

Intrauterine growth and survival were unaffected by compound administration at any dose level. Postimplantation losses in the treated groups were comparable to the control group value. The mean numbers of viable fetuses in the treated groups were also comparable to the control group value with one exception. The mean number of viable fetuses in the 361 mg/kg/day group (12.3 fetuses/dam) was slightly lower than the control group value (13.9 fetuses/dam). The low number of viable fetuses in the high dose group was due to lower mean numbers of corpora lutea and implantation sites in the 361 mg/kg/day group (15.9 corpora lutea/dam and 13.1 implantation sites/dam) than in the control group (17.5 corpora lutea/dam and 14.7 implantation sites/dam). As the numbers of corpora lutea and implantation sites are inherently determined prior to the initiation of dosing, no relationship to treatment was evident. The mean numbers of corpora lutea and implantation sites in the 36.1 and 180.5 mg/kg/day groups were comparable to the control group values. Mean fetal body weights and fetal sex ratios in all treated groups were comparable to the control group values. None of the differences between the control and treated groups were statistically significant.

FETAL MORPHOLOGICAL DATA

The numbers of fetuses (litters) available for fetal morphological examination were 305(22), 266(19), 330(23) and 271(22) in the control, 36.1, 180.5 and 361 mg/kg/day groups, respectively. The number of fetuses (litters) with malformations were 1(1), 1(1), 1(1), 0(0) in these same dose groups, respectively.

EXTERNAL MALFORMATIONS AND VARIATIONS

At the external examination, one fetus in the 180.5 mg/kg/day group (no. 20652-19) had multiple anomalies. These consisted of craniorachischisis, facial cleft, microphthalmia (unilateral) and ablepharia (bilateral). No other external malformations and no external developmental variations were observed at any dose level.

VISCERAL MALFORMATIONS AND VARIATIONS

Upon soft tissue examination, fetus no. 20661-7 in the 36.1 mg/kg/day group was hydrocephalic. The anomaly consisted of increased cavitation of the lateral and third ventricles. Control group fetus no. 20543-6 was observed with an encephalomeningocele (portion of brain and meninges protruded through an opening in the skull). No other soft tissue malformations were observed at any dose level.

Soft tissue developmental variations were observed in two control group fetuses (nos. 20655-10 and 20662-4). Both fetuses had renal papillae that were not developed and fetus no. 20662-4 also had a distended ureter. No other soft tissue developmental variations were noted.

SKELETAL MALFORMATIONS AND VARIATIONS

Multiple skeletal malformations were observed in a single fetus (no. 20652-19) in the 180.5 mg/kg/day group. This was the same fetus in which multiple malformations were noted at the external examination. The skeletal malformations consisted of a malformed clavicle and scapula and a vertebral anomaly with an associated rib anomaly (vertebral arches and/or ribs fused, extra, thickened or absent). No other skeletal malformations were observed at any dose level.

Skeletal developmental variations in all treated groups, such as cervical centrum no. I ossified, sternebrae nos. 5 and/or 6 unossified and 14th rudimentary ribs, occurred at a similar frequency in the control group, did not occur in a dose related manner and/or were within the range of the WIL historical control data. All other skeletal variants occurred infrequently (generally in single fetuses) or occurred similarly in the control group.

SUMMARY OFEXTERNAL. VISCERAL AND SKELETAL EXAMINATIONS

Fetal external, soft tissue, and skeletal malformations were observed in 1(1), 1(1), 1(1) and 0(0) fetuses (litters) in the control, 36.1, 180.5 and 361 mg/kg/day groups, respectively, and were considered to be spontaneous in ongm. No treatment related trends were apparent when either the actual numbers of malformations were compared or when the specific types of anomalies expressed were considered. None of the values in the treated groups were statistically significant when compared to the control group values. Fetal developmental variations in the treated groups were observed at a frequency similar to that in the control group, occurred infrequently or were within the range of the WILL historical control data.

Applicant's summary and conclusion

Conclusions:

In this study administration of Phosphoric acid, C9-15 branched and linear alkyl esters, potassium salts to 25 female Sprague-Dawley Crl:CD® BR rats/dose by oral gavage from day 6 through 15 of gestation had no compound related effects up to and including the highest tested dose of 361 mg/kg/day (active ingredient). Intrauterine growth and survival were unaffected by treatment at any dose level. The fetal malformations observed in this study were all considered to be spontaneous in origin. No treatment-related fetal developmental variations were observed at any dose level.

Executive summary:

In a developmental toxicity study according to OECD guideline 414, Phosphoric acid, C9-15 branched and linear alkyl esters, potassium salts (36.1% a.i.) was administered to 25 female Sprague-Dawley Crl:CD® BR rats/dose by oral gavage at dose levels of 0 (control), 36.1, 180.5 and 361 mg/kg bw/day (active ingredient) from day 6 through 15 of gestation. Females were sacrificed on day 21 post coitum and the fetuses were removed by Caesarean section.

No treatment-related effects on mortality, number of abortions, clinical signs, food consumption, gross pathology, intrauterine growth and survival (incl. postimplantation loss, viable litter size, mean fetal body weights, fetal sex ratios, mean numbers of corpora lutea and implantation sites) were observed.

No treatment-related fetal malformations or fetal developmental variations were observed at any dose level.

The NOEL for maternal toxicity is 36.1 mg/kg bw/day.

The NO(A)EL for maternal toxicity is 361 mg/kg bw/day (highest dose administered).

The NOEL for developmental toxicity is 361 mg/kg bw/day (highest dose administered).

The NOEL for embryotoxicity is 361 mg/kg bw/day (highest dose administered).

The NOEL for fetotoxicity is 361 mg/kg bw/day (highest dose administered).

The NOEL for teratogenicity is 361 mg/kg bw/day (highest dose administered).

The developmental toxicity study in the rat is classified acceptable and satisfies the guideline requirement for a developmental toxicity study (OECD 414) in rat.