2,2'-[(1-methylethylidene)bis(4,1-phenyleneoxymethylene)]bisoxirane

Repeated dose toxicity: dermal

Administrative data

Endpoint:

sub-chronic toxicity: dermal

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1995-02-20-1995-05-25

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Study was conducted according to GLP as well as Guidelines.

Cross-reference

Cross-reference 1

Reason / purpose for cross-reference:

reference to same study

Cross-reference 2

Reason / purpose for cross-reference:

reference to other study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1996

Report date:

1996

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 411 (Subchronic Dermal Toxicity: 90-Day Study)

Test guideline 2

Qualifier:

according to guideline

Guideline:

EPA OPP 82-3 (Subchronic Dermal Toxicity 90 Days)

Test guideline 3

Qualifier:

according to guideline

Guideline:

other: EEC Directive 87/302 Sub-Chronic dermal toxicity study

GLP compliance:

yes

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

4,4'-Isopropylidenediphenol, oligomeric reaction products with 1-chloro-2,3-epoxypropane

EC Number:

500-033-5

EC Name:

4,4'-Isopropylidenediphenol, oligomeric reaction products with 1-chloro-2,3-epoxypropane

Cas Number:

25068-38-6

Molecular formula:

(C15 H16 O2 . C3 H5 Cl O)x

IUPAC Name:

4,4'-Isopropylidenediphenol, oligomeric reaction products with 1-chloro-2,3-epoxypropane

Constituent 2

Reference substance name:

2,2'-[(1-methylethylidene)bis(4,1-phenyleneoxymethylene)]bisoxirane

EC Number:

216-823-5

EC Name:

2,2'-[(1-methylethylidene)bis(4,1-phenyleneoxymethylene)]bisoxirane

Cas Number:

1675-54-3

Molecular formula:

C21H24O4

IUPAC Name:

2,2'-[propane-2,2-diylbis(4,1-phenyleneoxymethylene)]dioxirane

Details on test material:

BADGE (CASRN 1675-54-3) was determined to be 99.65% pure by gas chromatography using area percent quantitation. The identity of the test material was confirmed through the use of gas / chromatography / mass spectrometry using the electron impact mode. A subsequent re-analysis confirmed the stability of the test material.

Test animals

Species:

mouse

Strain:

B6C3F1

Sex:

male

Details on test animals or test system and environmental conditions:

B6C3F1 male mice were obtained from a commercial supplier, examined by a laboratory veterinarian for general health status, and allowed to acclimate to the laboratory for 12 days prior to study start. Animals were randomized into dose groups based on body weights by a computer randomization program. Animals were identified via a subcutaneously-implanted transponder correlated to a unique animal identificatiom number.

Animal room temperature, humidity, air changes, and photocycle were maintained appropriate to the species. Animals were provided water and food ad libitum, and housed one per cage. Water was analyzed for contaminants at the municipal water source, and feed was analyzed for nutritional content and contaminants by the supplier.

Administration / exposure

Type of coverage:

open

Vehicle:

acetone

Details on exposure:

Dose solution concentrations were based on the expected average body weights over the duration of the 13 week study. The dose solutions were prepared by dissolving test material in acetone. Mice were dosed dermally with solutions of 0%, 0.05%, 0.5%, or 5% BADGE (w/v). Dose solutions were administered as a fixed volume (50ug/mouse/application). The dose was delivered by pipette to the clipped area of the back (approximately 10% surface area) of each mouse. The treated area was not covered, nor was the skin cleansed following treatment.

Groups of 10 male mice per dose level were dosed dermally with BADGE in acetone. Each animal was dosed 3 times per week

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

The stability of the test material in acetone was determined concurrent with the start of the study. Samples of the 0.05% solutions were analyzed periodically to verify stability in the vehicle. Homogeneity of the low and high dose solutions was evaluated concurrently with the conduct of the study. Concentration verification of all dose solutions was confirmed pre-study and after week 1 (as a result of a procedural change in dose solution preparation).

Duration of treatment / exposure:

13 weeks

Frequency of treatment:

3 times/week

Doses / concentrations

Remarks:

Doses / Concentrations:
0, 1, 10, 100 mg/kg/day
Basis:
other: nominal

No. of animals per sex per dose:

10 male mice/dose

Control animals:

yes, concurrent vehicle

Details on study design:

Groups of 10 male mice per dose level were dosed dermally with BADGE in acetone. Each animal was dosed 3 times per week.

Body weights and food consumption were measured weekly, and a daily observation was conducted to evaluate general animal disposition and the availability of feed and water. The dermal application site was evaluated for signs of irritation according to the dermal irritation scoring system recommended by the OECD (1981) on a daily basis the first week of the study, and weekly thereafter for the duration of the study. Clinical examinations were conducted prior to study start and weekly throughout the study and included evaluations of the skin, fur, mucous membranes, respiration, central nervous system function, swelling, masses, and general behavior.

Ophthalmological examinations were conducted on all mice prior to study start and at necropsy.

Clinical Pathology / Chemistry / hematology parameters were evaluated: hematocrit, hemoglobin, erythrocyte count, total leukocyte count, platelet count, differential counts of luekocytes, morphology of erythrocytes, leukocytes, and platelets, enzyme activity (alkaline phosphatase, alanine aminotransferase, aspartate aminotransferase), urea nitrogen, creatinine, total protein, albumin, globulin, glucose, total bilirubin, electrolytes (Na, K, P, Cl, Ca), cholesterol, and triglycerides.

Absolute and relative weights were collected for the brain, liver, heart, kidneys, and testes. All tissues from the control and high dose groups were evaluated, including all reproductive organs and tissues. In addition, tissues in lower dose levels including liver, kidneys, lungs, and skin from the dermal test site and a control site were evaluated.

Positive control:

No

Examinations

Observations and examinations performed and frequency:

Body weights and food consumption were measured weekly, and a daily observation was conducted to evaluate general animal disposition and the availability of feed and water. The dermal application site was evaluated for signs of irritation according to the dermal irritation scoring system recommended by the OECD (1981) on a daily basis the first week of the study, and weekly thereafter for the duration of the study. Clinical examinations were conducted prior to study start and weekly throughout the study and included evaluations of the skin, fur, mucous membranes, respiration, central nervous system function, swelling, masses, and general behavior.

Ophthalmological examinations were conducted on all mice prior to study start and at necropsy.

Sacrifice and pathology:

Clinical Pathology / Chemistry / hematology parameters were evaluated: hematocrit, hemoglobin, erythrocyte count, total leukocyte count, platelet count, differential counts of luekocytes, morphology of erythrocytes, leukocytes, and platelets, enzyme activity (alkaline phosphatase, alanine aminotransferase, aspartate aminotransferase), urea nitrogen, creatinine, total protein, albumin, globulin, glucose, total bilirubin, electrolytes (Na, K, P, Cl, Ca), cholesterol, and triglycerides.

Absolute and relative weights were collected for the brain, liver, heart, kidneys, and testes. All tissues from the control and high dose groups were evaluated, including all reproductive organs and tissues. In addition, tissues in lower dose levels including liver, kidneys, lungs, and skin from the dermal test site and a control site were evaluated.

Other examinations:

no additional examinations conducted

Statistics:

Descriptive statistics only (means and standard deviations) are reported for feed consumption, feed efficiency and leukocyte differential counts. Body weights, organ weights, clinical chemistry data, and appropriate hematologic data are evaluated by Bartlett's test for equality of variances. Based on the outcome of Bartlett's test, exploratory data analysis is performed by a parametric or nonparamet-ric analysis of variance (ANOVA), followed respectively by Dunnett's test or the Wilcoxon Rank- Sum test with a Bonferroni correction for multiple comparisons. Statistical outliers are identified by a sequential test, but routinely excluded only from feed ' consumption statistics. Outliers may be excluded from other analyses only for documented, scientifically sound reasons, unrelated to treatment.

The nominal alpha levels to be used and test references are as follows:

Bartlett's test (Winer, 1971) α = 0.01
Parametric ANOVA (Steel and Torrie, 1960) α = 0.10
Nonparametric ANOVA (Hollander and Wolfe, 1973) α = 0.10
Dunnett's test (Winer, 1971) α = 0.05 two-sided
Wilcoxon Rank-Sum test (Hollander and Wolfe, 1973) α = 0.05
(Bonferroni correction - Miller, 1966) two-sided
Outlier test (Grubbs, 1969) α = 0.02 two-sided

Because numerous measurements are compared statistically on the same group of animals, the frequency of false positive (Type 1) errors is unknown, but is much greater than the nominal alpha.

The final toxicologic interpretation of the data considers other factors, such as dose- response relationships, biological plausibility and consistency, and historical rates.

Results and discussion

Results of examinations

Clinical signs:

no effects observed

Dermal irritation:

effects observed, treatment-related

Mortality:

no mortality observed

Body weight and weight changes:

no effects observed

Food consumption and compound intake (if feeding study):

no effects observed

Food efficiency:

not examined

Water consumption and compound intake (if drinking water study):

not examined

Ophthalmological findings:

no effects observed

Haematological findings:

no effects observed

Clinical biochemistry findings:

no effects observed

Urinalysis findings:

not examined

Behaviour (functional findings):

not examined

Organ weight findings including organ / body weight ratios:

effects observed, treatment-related

Gross pathological findings:

effects observed, treatment-related

Histopathological findings: non-neoplastic:

effects observed, treatment-related

Histopathological findings: neoplastic:

no effects observed

Details on results:

Concentrations of the dose levels were determined ot be 94-97% of the targeted concentrations. Homogeneity of the solutions was verified; a standard of deviation and percent relative standard deviation were considered within acceptable limits.

There were no treatment-related effects in the following parameters: ophthalmology, in-life observations, body weights and weight gains, feed consumption, and clinical chemistry and hematology parameters that were evaluated. Two control mice were observed on test days 1 and 3 with scab formation where the skin was disturbed during clippind and transponder implantation. The scabs were resolved by test day 5, and no other treatment-related irritation was noted.

Mice administered 1 mg/kg/day had statistically-identified increased absolute brain weights, but a lack of dose-response led authors to dismiss it as not related to treatment. Liver weights at the high dose were increased, but were not accompanied by histopathological findings and were still lower than historical control values for the laboratory. The finding is of doubtful toxicological significance.

There were no gross lesions attributed to treatment, and no indication of systemic pathologic effects supported by histopathology. Histopathologic changes in the skin, however, were not confined to the test site, but were less marked in nature than the test site. The changes in skin were characterized as a very slight to moderate epidermal hyperplasia with very slight to moderate subacute inflammation. In some cases, slight follicular spongiosis, characterized by intraepithelial edema in the epidermis or at the neck of the follicle, was noted. Very slight focal or multifocal parakeratosis was observed in a few mid and high dose animals. Micro abscesses in either the epidermis or neck of the follicle, were observed in one mid dose and one high dose animal. Together, the findings suggest chronic active dermatitis.

Effect levels

1

Dose descriptor:

NOAEL

Effect level:

100 other: mg/kg/application

Sex:

male/female

Basis for effect level:

other: Systemic toxicity was unaffected by dermal application of 100 mg/kg/day administered three times/week.

2

Dose descriptor:

NOAEL

Effect level:

>= 1 other: mg/kg/application

Sex:

male/female

Basis for effect level:

other: At the application site, mild to moderate chronic active dermatitis with a weak dose-response was observed histopathologically at doses of 1-100 mg/kg/application DGEBPA administered three times/week.

Remarks on result:

not determinable

Remarks:

no NOAEL identified

Target system / organ toxicity

Critical effects observed:

not specified

Any other information on results incl. tables

DGEBPA applied to the skin of male BCC3F1 mice three times per week for thirteen weeks at dosages of 1,10 or 100 mg/kg/application caused no

systemic toxicity. Mild to moderate chronic active dermatitis with a weak dose-response was observed histopathologically at dosages up to 100 mg/kg/application DGEBPA. Spongiosis and epidermal micro abscess formation indicated that the maximum-tolerated-dose (MTD) was met in

mice administered 100 mg/kg/application DGEBPA. The no-observed-effect level (NOEL) for dermal effects was not determined.

Applicant's summary and conclusion

Conclusions:

There was no systemic toxicity noted up to 100 mg/kg/day. Mild to moderate chronic active dermatitis with a weak dose-response was observed histopathologically at doses up to 100 mg/kg/day. Spongiosis and epidermal micro-abscesses indicated that the maximum-tolerated-dose was met at 100 mg/kg/day. NOEL for DGEBPA in mice dosed dermally was not determined.

Executive summary:

Diglycidyl ether of bisphenol A (DGEBPA), CAS# 1675-54-3, was evaluated for dermal irritation and systemic toxicity potential following approximately 13-weeks of repeated dermal administration. Groups of 10 B6C3F1 male mice/dose level were dosed dermally with DGEBPA in acetone solutions at concentrations of 0, 0.05%, 0.5%, or 5.0% (wlv). The dosing volume was 50 pllapplication which corresponded to approximate dosages of 0, 1, 10, or 100 mg DGEBPA/kg body weighvapplication. Each dose group followed a 3 applications/week (Monday, Wednesday, Friday) dosing regimen resulting in each animal receiving a total of 41 applications during the study. Data were collected on the following: clinical appearance and behavior, dermal irritation at the test site, body weights, food consumption, clinical pathology, gross pathology, and histopathologic appearance of the treated and untreated test sites.

DGEBPA applied to the skin of male B6C3F1 mice three times per week for thirteen weeks at dosages of 1, 10 or 100 mg/kg/application caused no apparent systemic toxicity. Mild to moderate chronic active dermatitis with a weak dose-response was observed histopathologically at dosages up to 100 rng/kg/application DGEBPA. Spongiosis and epidermal micro abscess formation indicated that the maximum-tolerated-dose (MTD) was met in mice administered 100 mg/kg/application DGEBPA. A no-observed-effect level (NOEL) for dermal effects was not determined.