Maleic anhydride

Toxicity to reproduction

Administrative data

Endpoint:

multi-generation reproductive toxicity

Remarks:

based on test type (migrated information)

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: comparable to guideline study

Data source

Reference

Reference Type:

publication

Title:

Teratology and multigeneration reproduction studies with maleic anhydride in rats.

Author:

Short RD, Johannsen FR, Levinskas G J, Rodwell DE & Schardein JL.

Year:

1986

Bibliographic source:

Fundam. Appl. Toxicol. 7: 359-366.

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 416 (Two-Generation Reproduction Toxicity Study)

Deviations:

yes

Remarks:

three-generation study

GLP compliance:

not specified

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

Maleic anhydride

EC Number:

203-571-6

EC Name:

Maleic anhydride

Cas Number:

108-31-6

Molecular formula:

C4H2O3

IUPAC Name:

furan-2,5-dione

Details on test material:

Maleic anhydride (99.7%)

Test animals

Species:

rat

Strain:

Sprague-Dawley

Sex:

male/female

Details on test animals or test system and environmental conditions:

Adult CD rats (Charles River Breeding Laboratories, Wilmington, Mass.), approximately 12 weeks of age, were used in the teratology study.
All rats were acclimated to the laboratory for at least 10 days prior to initiating a study. Rats were individually housed, except during mating and lactation, in wire mesh cages or plastic cages with corn-cob bedding. All animals were maintained in environmentally controlled rooms with 12-hr photoperiods and given free access to feed (Purina Rodent Chow, Ralston-Purina, St. Louis, Mo.) and water.

Administration / exposure

Route of administration:

oral: unspecified

Vehicle:

corn oil

Details on exposure:

Maleic anhydride was suspended in corn oil as described previously; however, the concentration was varied so that the desired dose could be administered orally in a volume of 10 ml/kg.

Details on mating procedure:

During the mating period each male was housed with two females for up to 15 days. The females were examined daily for evidence of mating as revealed by vaginal plugs or sperm-positive vaginal smears.

Analytical verification of doses or concentrations:

not specified

Details on analytical verification of doses or concentrations:

no data

Duration of treatment / exposure:

Exposure period: Pre-mating and throughout mating, gestation and lactation.
Premating exposure period: F0 and F1, a minimum of 80 days

Frequency of treatment:

Frequency of treatment: 7 days/week

Doses / concentrations

Remarks:

Doses / Concentrations:
0,20, 55, and 150 mg/kg
Basis:
nominal in diet

No. of animals per sex per dose:

10 males and 20 females per group

Control animals:

yes, concurrent no treatment

Details on study design:

no data

Positive control:

no

Examinations

Parental animals: Observations and examinations:

yes

Oestrous cyclicity (parental animals):

no data

Sperm parameters (parental animals):

no data

Litter observations:

yes

Postmortem examinations (parental animals):

yes

Postmortem examinations (offspring):

yes

Statistics:

Statistical analysis: Several different statistical methods were used to compare measurements made on test animals to the corresponding values determined for controls. The methods and the measurements to which they were applied are analysis of variance and Dunnett's test (Steel and Torrie, 1960) for adult body weights, litter size, and pup body weights; Fisher's exact probability test (Siegel, 1956) for mortality and fertility data; Mann-Whit-ney U test (Siegel, 1956) for fetal body weights; and x2 test with Yates' correction or Fisher's exact probability test (Siegel, 1956) for litters with anomalies. In all instances, p < 0.05 was selected as the level of significance.

Reproductive indices:

no data

Offspring viability indices:

no data

Results and discussion

Results: P0 (first parental generation)

General toxicity (P0)

Clinical signs:

effects observed, treatment-related

Body weight and weight changes:

effects observed, treatment-related

Food consumption and compound intake (if feeding study):

effects observed, treatment-related

Organ weight findings including organ / body weight ratios:

not specified

Histopathological findings: non-neoplastic:

effects observed, treatment-related

Other effects:

effects observed, treatment-related

Reproductive function / performance (P0)

Reproductive function: oestrous cycle:

not specified

Reproductive function: sperm measures:

not examined

Reproductive performance:

not specified

Details on results (P0)

With the exception of a few cases of respiratory rales, the clinical appearance and behavior of these F0 rats were not remarkably different from those of their controls. Respiratory rales also occurred in F1l rats, and the incidence and severity appeared to increase with dose. In addition, these rats often vigorously resisted handling at the time of dosing. This behavior may be related to irritating effects of maleic anhydride or a taste aversion to the test material. In the F0 generation, significant mortality occurred in adults of both sexes from the high-dose group. The F1 generation had a greater number of deaths, many of which were attributed to gavage-related injuries. If these traumatic deaths are omitted, mortality in the F1 generation tended to parallel that of the F0 generation except for the increase recorded for low-dose males. One animal in the latter group died of interstitial pneumonia.
While no cause could be identified, the three other deaths in this group are not believed to be compound-related because no deaths among mid-dose males were attributed to the test material and characteristic compound-induced lesions discussed subsequently were not noted.
Adult body weights were not affected in the low-dose groups. While there were some differences in mean body weights between control animals and those of the mid-dose group, none of the differences was statistically significant. In the high-dose group, mean body weights of both sexes of the F0 generation were significantly reduced by Week 11, and this reduction persisted for the remainder of the test. The F1 generation showed a pattern that was roughly similar, except that the only significantly depressed mean body weight occurred in high-dose males at 30 weeks.
Fertility was significantly reduced in the experimental groups at several times. However, there was neither a dose-related reduction nor a pattern within a generation hat suggested the presence of a treatment-reated effect.

Effect levels (P0)

Dose descriptor:

LOAEL

Effect level:

20 mg/kg bw/day

Sex:

male/female

Results: F1 generation

General toxicity (F1)

Clinical signs:

not specified

Mortality / viability:

not specified

Body weight and weight changes:

effects observed, treatment-related

Sexual maturation:

no effects observed

Organ weight findings including organ / body weight ratios:

no effects observed

Gross pathological findings:

no effects observed

Histopathological findings:

no effects observed

Details on results (F1)

Treatment with maleic anhydride had no effect on litter size or on pup survival at doses up to 150 mg/kg/day in the F1a and F1b litters and at doses up to 55 mg/kg/day in the F2a and F2b litters. Pup body weights in the experimental groups were significantly reduced at a few of the observation periods. In the low- and mid-dose groups, pup weights were significantly reduced only at weaning of the F2b litters. However, these effects were observed only in one litter of a generation, and there was no pattern beween litters of a generation or between generations that suggested the presence of a treatment-related effect.
In addition, the examination of tissues from F2b pups revealed no compound-related changes in organ weights or in incidences of microscopic lesions.

Effect levels (F1)

Dose descriptor:

NOAEL

Generation:

F1

Effect level:

55 mg/kg bw/day

Sex:

male/female

Results: F2 generation

Effect levels (F2)

Dose descriptor:

NOAEL

Generation:

F2

Effect level:

55 mg/kg bw/day

Sex:

male/female

Overall reproductive toxicity

Reproductive effects observed:

not specified

Any other information on results incl. tables

In addition to treatment-related deaths, there were also gavage-related deaths in this study. If allowance is made for the latter, it appears that treatment-related mortality in the F0 generation occurred primarily in the high-dose group. Although mortality was observed at lower doses in the Fl generation, there was no dose-related pattern at these levels that suggested an effect related to treatment. Therefore, in the Fl generation, mortality that can reasonably be attributed to treatment also occurred primarily at high dose. As a result of increased mortality, this dose group was terminated during the F1 generation.

Since there was a significant reduction in neither the percentage of pregnant females nor the percentage of fertile males, it is concluded that no adverse effects on fertility were observed with maleic anhydride at doses up to 55 mg/kg/day administered over two generations. At 150 mg/kg/day, maleic anhydride was toxic to parental animals.

No adverse effects on litter size and on pup survival were observed with maleic anhydride at doses up to 150 mg/kg/day in F1 and F1 b litters or 55 mg/kg/day in F2a and F2b litters. Although a few statistically significant changes in pup body weights were observed, they were too inconsistent to be considered treatment-related. Microscopic examination of tissues from pups in the F2b litters revealed no treatment-related changes. Therefore, treatment with up to 55 mg/kg/day for two generations had no adverse effects on pups.

TABLE 1 MORTALITY AND BODY WEIGHT OF ADULT RATS TREATED WITH MALEIC ANHYDRIDE DURING A MULTIGENERATION REPRODUCTION STUDY

	Maleic anhydride (mg/kg/day)
	0	20	55	150
Fo generation
Males
Mortality a	0(0)	10(10)	10(0)	70b(60)b
Body weight c	143	142	143	143
	502	524	506	431b
	700	697	666	562b
Females
Mortality a	0(0)	0(0)	5(0)	65(65)b
Body weight c	129	130	130	127
	289	281	280	259b
	368	345	337	317b
Fl generation
Males
Mortality a	20(0)	40(40)b	40(0)	75b(58)b
Body weight c	113	107	103	85b
	495	500	445	431
	722	703	683	—
Females
Mortality a	20(0)	30(5)	52b(10)	100b(14)
Body weight c	96	100	95	84
	265	272	265	247
	334	343	347	—

a Total dead/total treated X 100 (% mortality minus gavage-related deaths). Groups contained 10 to 12 males and 20 to 21 females.

b Significantly different from the appropriate control.

c Body weight (g/rat) at Weeks 0, 11, and 32 of the study.

d Body weights (g/rat) at Weeks 30,41, and 61 of the study.

 

 

Table 2FERTILITY OF RATS TREATED WITH MALEIC ANHYDRIDE DURING A MULTIGENERATION REPRODUCTION STUDY

	Maleic anhydride (mg/kg/day)
	0	20	55	150
Females
Fla	14/20(70)a	7/20(35)b	14/20(70)	7/20(35)b
Fib	10/20(50)	8/2(40)	11/19(58)	6/10(60)
F2a	14/20(70)	13/15(87)	9/11(82)	—
F2b	12/16(75)	12/14(86)	8/10(80)	—
Males
Fla	8/10(80)c	5/10(50)	9/10(90)	4/10(40)b
Fib	6/10(60)	5/9 (100)	7/10(70)	5/9(56)
F2a	9/10(90)	6/6 (100)	6/6 (100)	—
F2b	8/8(100)	7/7 (100)	5/5 (100)	—

a Number pregnant/number mated * 100 (% pregnant).

b Significantly different from control.

c Number fertile/number mated * 100 (% fertile).

 

 

Table 3LITTER SIZE OF RATS TREATED WITH MALEIC ANHYDRIDE DURING A MULTIGENERATION REPRODUCTION STUDY

	Maleic anhydride (mg/kg/day)
Litter	Days after birth	0	20	55	150
F1a	0	12.2a	11.0	11.6	13.1
	4	12.0(9.9)b	10.5(9.3)	11.2(9.3)	13.4(10.0)
	21	9.9	9.3	8.8	10.0
F1b	0	13.3	10.3	13.4	11.3
	4	13.0(9.8)	9.6 (9.0)	13.2(9.9)	10.8(9.7)
	21	9.8	8.9	9.8	9.3
F2a	0	13.4	12.2	12.0	—
	4	13.1(9.9)	11.6(10.0)	11.8(9.8)	—
	21	9.9	9.9	9.8	—
F2b	0	10.5	13.6	14.0	—
	4	10.4(8.2)	13.3(9.8)	13.8(10.0)	—
	21	8.2	9.7	9.0	—

a Mean live pups/litter on indicated day. The number of pregnant females that gave birth on Day 0 is presented in Table 2.

b Mean live pups/litter before litter reduction (mean live pups/litter after reduction to five pups/sex/litter when possible).

 

Table 4 BODY WEIGHT OF PUPS FROM RATS TREATED WITH MALEIC ANHYDRIDE DURING A MULTIGENERATION REPRODUCTION STUDY

	Maleic anhydride (mg/kg/day)
Litter	Days after birth	0	20	55	150
Fla	0	6.7a	6.6	6.7	5.8b
	4	12(11)c	11(11)	12(11)	10 (9)
	21	58(56)	54(53)	58(55)	46b (44)b
f1b	0	6.4	7.1b	6.2	6.3
	4	11(10)	12(12)	11(10)	10 (10)
	21	53(50)	54 (54)	51(50)	47 (46)
F2a	0	6.6	6.4	6.7	—
	4	11(10)	10(10)	10(10)	—
	21	47(45)	47 (46)	46 (45)	—
F2b	0	6.8	6.4	6.1	—
	4	11(11)	10(9)	9(9)	—
	21	50(57)	45 (44)b	43 (44)b	—

a Mean weight (g) of both males and females.

b Significantly different from control.

 

 

Applicant's summary and conclusion

Conclusions:

The NOAEL for reproductive effects was 55 mg/kg/day. For parental toxicity, however, the LOAEL was 20 mg/kg/day.

Executive summary:

These effects are likely to reflect the toxicity of maleic acid since maleic anhydride is rapidly hydrolyzed to maleic acid in the body, particularly by the oral route of exposure.