Phthalic acid

Genetic toxicity: in vivo

Administrative data

Endpoint:

in vivo mammalian somatic cell study: cytogenicity / erythrocyte micronucleus

Remarks:

Type of genotoxicity: chromosome aberration

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2007

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: No OECD guideline or GLP defined; short description

Data source

Reference

Reference Type:

publication

Title:

Unnamed

Year:

2007

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 474 (Mammalian Erythrocyte Micronucleus Test)

Principles of method if other than guideline:

Seven- to 8 -wk-old male ICR strain mice were subjected to the Micronucleus (MN) test. Animals were administered the test substance ip and were sacrificed 24 h after treatment. Bone marrow was extracted and numbers of micronucleated cells were determined by counting numbers of polychromatic erythrocytes (PCE) from among at least 1000 PCE per animal. Micronucleated polychromatic erythrocytes MNPCE) that contained micronuclei were counted from among at least 1000 PCE.

GLP compliance:

not specified

Type of assay:

micronucleus assay

Test material

Test material information

Constituent 1

Reference substance name:

Phthalic acid

EC Number:

201-873-2

EC Name:

Phthalic acid

Cas Number:

88-99-3

Molecular formula:

C8H6O4

IUPAC Name:

benzene-1,2-dicarboxylic acid

Details on test material:

Phthalic acid [C6H4-1,2-(COOH)2; Cas number 88-99-3]; no details about purity given.

Specific details on test material used for the study:

Supplier: Sigma; commercial grade can be suggested

Test animals

Species:

mouse

Strain:

ICR

Sex:

male

Administration / exposure

Route of administration:

intraperitoneal

Duration of treatment / exposure:

Animals were administered the test substance i.p. and were sacrificed 24h after treatment.

Frequency of treatment:

single dose

Post exposure period:

24h

Doses / concentrations

Remarks:

Doses / Concentrations:
20, 100, 500, 2500, 12500 µM/kg)
Basis:
no data

No. of animals per sex per dose:

5

Control animals:

yes, concurrent vehicle

Examinations

Tissues and cell types examined:

Bone marrow was extracted with fetal bovine serum (0.5 ml), and cell suspensions were centrifuges at 1000xg for 5 min. Number of micronucleated cells were determined by counting numbers of polychromatic erythrocytes (PCE) from among at least 1000 PCE per animal.Micronucleated polychromatic erythrocytes (MNPCE) that contained micronuclei were counted from among at least 1000 PCE.

Details of tissue and slide preparation:

MMC (positive control, 2 mg/kg) dissolved in sterile deionized water

Results and discussion

Test results

Sex:

male

Genotoxicity:

negative

Toxicity:

not specified

Vehicle controls validity:

valid

Negative controls validity:

other: Vehicle control= negative control

Positive controls validity:

valid

Any other information on results incl. tables

Micronucleus Induction in Mouse Bone Marrow Cells Treated with Phthalic Acid:

Samples	Treatments	Concentrations	Route	Number of mice tested	Exposure time (h)	MNPCE%^a(mean+ SD)	PCE/(PCE+NCE)^b (mean+SD)
Phthalic Acid	Control^c	0	i.p.	5	24	0.24 +0.05	0.11 +0.02
		20 µM/kg	i.p.	5	24	0.32 +0.34	0.15 +0.04
		100  µM/kg	i.p.	5	24	0.38 +0.35	0.13 +0.03
		500  µM/kg	i.p.	5	24	0.41 +0.25	0.16 +0.05
		2500  µM/kg	i.p.	5	24	0.31 +0.55	0.14 +0.02
		12500  µM/kg	i.p.	5	24	0.35 +0.26	0.18 +0.01
	MMC^d	2 mg/kg	i.p.	5	24	6.47 +0.54	0.62 +0.02

^aMicronucleated polychromatic erythrocytes/1000 polychromatic erythrocytes, ^bPolychromatic erythrocytes/1000 erythrocytes, ^cSample dilution buffer, ^dMitomycin C.

Applicant's summary and conclusion

Executive summary:

In a Micronucleus Assay in ICR strain mice the animals were injected i.p.with suspensions of test compound, which were treated as follows: group 1, vehicle alone (DMSO, negative control); groups 2, 3, 4, and 5 were treated with Phthalic Acid at 5 concentration levels (20, 100, 500, 2500, or 12500 µM/kg); and group 6 was treated with MMC (positive control, 2 mg/kg) dissolved in sterile deionized water. The animals were sacrificed 24 h after i.p. administration of the test substances. Micronuclei formations due to Phthalic Acid were evaluated using mouse bone marrow at concentrations up to 12500 µM/kg after 24 h of treatment. No mortalities were observed at these levels. Frequencies of MNPCE (micronucleated polychromatic erythrocytes/1000 polychromatic erythrocytes) in the vehicle control groups were 0.14% (PA). In general, MNPCE% was little higher for mouse bone-marrow cells treated with the test agent, but no concentration-response relationship was observed. PCE/(PCE+NCE) values were also elevated in cells treated with the test agents, but again no concentration-response relationship was found.

In conclusion, the findings of the present study suggest that phthalic acid is not genotoxic in the mutagenic test used.