Glycollic acid

Immunotoxicity

Description of key information

NOEL (immunotoxicity): 600 mg/kg bw/day (male/female). The NOEL is based on 100% glycolic acid dosed (adjusted for 70% purity of the test substance).
There were no treatment-related adverse effects on spleen or thymus and glycolic acid 70% solution did not affect the primary humoral immune response to SRBC.

Key value for chemical safety assessment

Effect on immunotoxicity: via oral route

Link to relevant study records

Reference

Endpoint:

immunotoxicity: sub-chronic oral

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: see 'Remark'

Remarks:

Guideline compliant Commission Directive 87/302/EEC, U.S. EPA Pesticide Assessment Guidlines Subdivision F, 82-1 ( 1982), OECD Test Guideline 407, Maff Japan NohSan No. 4200 ( 1985). This study was selected as the key study because the information provided for the hazard endpoint is sufficient for the purpose of classification and labelling and/or risk assessment.

Reason / purpose for cross-reference:

reference to same study

Qualifier:

equivalent or similar to guideline

Guideline:

EPA OPPTS 870.7800

Principles of method if other than guideline:

OECD Guideline 408 (Repeated Dose 90-Day Oral Toxicology in Rodents)
EPA OPP 82-1 (90-Day Oral Toxicology).

GLP compliance:

yes

Limit test:

no

Species:

rat

Strain:

other: Crl:CD (SD) IGS.BR

Sex:

male/female

Details on test animals or test system and environmental conditions:

Raised by: Charles River Laboratories, Inc., Raleigh, North Carolina, USA
Birthdated 18 August 1998. Rats were circa 5 weeks old at time of receipt. Group mean bodyweight range at time of allocation to study was 229.5 to 232.6g for males and 163.7 to 165.0g for females.
- Age at study initiation: 48 days
- Housing: all rats were housed one per cage, sexes separate, in stainless steel, wire-mesh cages suspended above cage boards.
- Diet (e.g. ad libitum): All rats were fed PMI Nutrition International, Inc. Certified Rodent Checkers LabDiet@ 5002 ad libitum.
- Water (e.g. ad libitum): Tap water was provided ad libitum
- Acclimation period: Upon arrival at Haskell Laboratory, the rats were quarantined for six days of the 13-day pretest period.
ENVIRONMENTAL CONDITIONS
- Temperature (°C): 23" +/- 1°C
- Humidity (%): 50% +/- 10%
- Photoperiod (hrs dark / hrs light): 12-hour light/dark cycle (fluorescent light)

Route of administration:

oral: gavage

Vehicle:

water

Details on exposure:

Dose solutions were prepared at 15, 30 and 60 mg/mL on a daily basis and administered on same day by gavage in a dose volume of 10 mL/kg bw.
The solutions were administered daily by oral gavage at a dose volume of 10 ml/kg, to achieve dose levels of 150, 300, and 600 mg/kg/day, based on the most recently recorded weight. Dosing solutions were stored refrigerated until used. Dosing solutions stored beyond 14 days after preparation were not administered to animals. Control animals were dosed with commercially-supplied water only.

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

HPLC: Hewlett-Packard 1090; UV 210 nm; column: Zorbax® SB-C18, 4.6 mm x 150 mm; 40°C mobile phase: 2.0% acetonitrile/98.0% 3.1 mM H3P04; 1.0ml/min., Injection volume: 4.0 µl
From each dosing solution sample, 1 mL was aliquoted and diluted to 10 mL with high performance liquid chromatography (HPLC) grade water, then mixed. The 0 mg/mL and 15 mg/mL solutions were analyzed without further dilution. The 30 mg/mL and 60 mg/mL samples were further diluted with HPLC grade water to an expected concentration of 1.5 mg/mL active ingredient (a.i.) prior to analysis. Samples submitted for analysis were analyzed the day the solutions were prepared by the testing group.

Duration of treatment / exposure:

28 days animals were sacrificed on day 29

Frequency of treatment:

Daily

Remarks:

Doses / Concentrations:
150, 300 or 600 mg/kg bw 15, 30 and 60 mg/mL administered in 10 mL/kg bw volume of water
Basis:
nominal in water

No. of animals per sex per dose:

10/sex/dose level

Control animals:

yes, concurrent vehicle

Details on study design:

See study design table in "other information section".
- Dose selection rationale: Dose levels for this study were selected based on results from a developmental toxicity study in which glycolic acid was administered by gavage to Crl:CD%R female rats (25/group) on days 7-21 of gestation at daily dose levels of 0, 75, 150, 300, or 600 mg/kg/day.
- Rationale for animal assignment (if not random): Rats were selected for study use on the bases of adequate body weight gain, freedom from any
clinical signs of disease or injury, and a body weight within 20% of the mean within a sex. The selected rats were distributed by computerized, stratified randomization so that there were no statistically significant differences among group body weight means within a sex.
- On test day 23, animals designated for immunotoxicity evaluation were injected intravenously in the lateral tail vein with 0.5 mL of 4x108 Sheep Red Blood Cells (SRBC)/mL. Six days after injection, on test day 29, the animals were euthanized by carbon dioxide anesthesia and exsanguination. Following sacrifice, the spleen and thymus were removed from each rat and weighed and serum was collected from each rat and analyzed for SRBC-specific IgM antibody. Sera previously collected from rats injected with SRBC and dosed with the known immunosuppressive agent cyclophosphamide were
analyzed for SRBC-specific IgM antibody concurrently with the study samples as a positive control.

Observations and clinical examinations performed and frequency:

CAGE SIDE OBSERVATIONS: Yes
- Time schedule: daily

DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule: Cage-site examinations to detect moribund or dead rats and abnormal behavior and appearance among rats were conducted at least once daily throughout the study. Moribund and dead rats were submitted for a gross and microscopic examination. At every weighing, each rat was
individually handled and examined for abnormal behavior and appearance. Rats designated for neurotoxicity evaluations had cage-site examinations approximately one to two hours after dosing on test day 1, and approximately one to two hours after dosing on one day during the weeks that the functional observational battery was conducted.

BODY WEIGHT: Yes
- Time schedule for examinations: All rats were weighed once per week during the 90-day feeding phase of the study. In addition, the neurotoxicity substudy rats were weighed on the days of neurotoxicity evaluation.

FOOD CONSUMPTION AND COMPOUND INTAKE (if feeding study)/ FOOD EFFICIENCY
The amount of food consumed by each rat over each weighing interval was determined throughout the study. From these determinations and body weight data, mean daily food consumption and mean food efficiency were calculated.

Sacrifice and pathology:

Day 29 / thymus + spleen weights.
Sera collected for ELISA for SRBC
GROSS PATHOLOGY: Yes- spleen and thymus
HISTOPATHOLOGY: Yes - spleen and thymus

Humoral immunity examinations:

- Humoral Immune Function and Immune Organ Weights
- Test day 23, 10 animals/sex/dose injected iv w/ Sheep Red Blood Cells.
- Test day 29 animals sacrificed
- Spleen and Thymus removed and weighed
- Serum collected and analyzed for IgM antibody
There were no statistically significant differences in the primary humoral immune response to SRBC for male or female rats at any dosage of glycolic acid in this study.
A statistically significant decrease compared to control of 56% and 66%, respectively, in the primary humoral immune response to SRBC was observed for male and female rats dosed for six days with 20mg/kg/day cyclophosphamide, the positive control material. Therefore, the SRBC-specific ELISA test system was valid for this sutdy with glycolic acid.

Other functional activity assays:

No further information.

Other examinations:

No further information.

Positive control:

A positive control study involved collecting sera from animals previously injected with SRBC and the immunosuppressive agent, Cyclophosphamide. Serum was analysed for SRBC-specific IgM antibody.

Statistics:

No further information.

Clinical signs:

effects observed, treatment-related

Mortality:

mortality observed, treatment-related

Body weight and weight changes:

effects observed, treatment-related

Food consumption and compound intake (if feeding study):

effects observed, treatment-related

Ophthalmological findings:

effects observed, treatment-related

Haematological findings:

effects observed, treatment-related

Clinical biochemistry findings:

effects observed, treatment-related

Urinalysis findings:

effects observed, treatment-related

Gross pathological findings:

effects observed, treatment-related

Details on results:

A statistically significant decrease of 17% compared to control in mean absolute spleen weight was observed for the 600 mg/kg/day male dose group sacrificed at day 29. The decreased spleen weight for the 600 mg/kg/day male dose group, however, was considered secondary to test-substance induced lower mean body weight, and, therefore, was not considered an immunotoxic effect. No statistically significant alterations in either the mean absolute or relative spleen and thymus weights were observed in male and female rats at any dosage. Therefore, glycolic acid did not produce test-substance-related adverse effects on the spleen or thymus weights of either male or female rats.

There were no statistically significant differences in the primary humoral immune response to SRBC for male or female rats at any dosage of glycolic acid in this study.

A statistically significant decrease compared to control of 56% and 66%, respectively, in the primary humoral immune response to SRBC was observed for male and female rats dosed for six days with 20mg/kg/day cyclophosphamide, the positive control material. Therefore, the SRBC-specific ELISA test system was valid for this sutdy with glycolic acid.

Cell viabilities:

effects observed, treatment-related

Humoral immunity examinations:

effects observed, treatment-related

Specific cell-mediated immunity:

effects observed, treatment-related

Non-specific cell-mediated immunity:

effects observed, treatment-related

Other functional activity assays:

effects observed, treatment-related

Other findings:

effects observed, treatment-related

Dose descriptor:

NOEL

Effect level:

600 mg/kg bw/day (actual dose received)

Sex:

male/female

Basis for effect level:

other: There were no treatment-related adverse effects on spleen or thymus and glycolic acid 70% solution did not affect the primary humoral immune response to SRBC.

A. Organ Weights

-A statistically significant decrease of 17% compared to control in mean absolute spleen weight was observed for the 600 mg/kg/day male dose group sacrificed at day 29. The decreased spleen weight for the 600 mg/kg/day male dose group, however, was considered secondary to test substance induced lower mean body weight, and, therefore, was not considered an immunotoxic effect. No statistically significant alterations in either the mean relative spleen and thymus or absolute thymus weights were observed in male rats at any dosage. No statistically significant differences in either the mean absolute or relative spleen and thymus weights were observed in female rats at any dosage. Furthermore, glycolic acid did not produce test substance-related alterations in splenic or thymic histopathology at any dosage in either male or female rats following 90 days of exposure. Therefore, glycolic acid did not produce test substance-related adverse effects on the spleen or thymus weights of either male or female rats.

B. Humoral Immune Function

- There were no statistically significant differences in the primary humoral immune response to SRBC for male or female rats at any dosage of glycolic acid in this study. - A statistically significant decrease compared to control of 56% and 66%, respectively, in the primary humoral immune response to SRBC was observed for male and female rats dosed for six days with 20 mg/kg/day cyclophosphamide, the positive control material. Therefore, the SBC-specific ELISA test system was valid for this study with glycolic acid.

Conclusions:

No test-substance -related adverse effects on spleen or thymus were observed in this study. Glycolic acid did not decrease the primary humoral immune response to SRBC of either male or female rats. Based on these data, the immune system does not appear to be a primary target of toxicity for glycolic acid in rats. Under the conditions of this study, the NOEL for immunotoxicology endpoints for both male and female rats was 600 mg/kg/day glycolic acid, the highest dosage tested. Under the conditions of this study, the NOEL for immunotoxicology endpoints for noth male and female rats was 600 mg/kg/day glycolic acid, the highest dosage tested. The study and the conclusions which are drawn from it fulfill the quality criteria (validity, reliability, repeatability).

Executive summary:

No test-substance -related adverse effects on spleen or thymus were observed in this study. Glycolic acid did not decrease the primary humoral immune response to SRBC of either male or female rats. Based on these data, the immune system does not appear to be a primary target of toxicity for glycolic acid in rats.

Under the conditions of this study, the NOEL for immunotoxicology endpoints for noth male and female rats was 600 mg/kg/day glycolic acid, the highest dosage tested.

Additional information

Immune function organ weights were recorded in a 90-day sub-chronic rat oral toxicity study. A decrease in mean absolute spleen weight was observed for the 600 mg/kg/day male dose group. This was considered secondary to test substance induced lower mean body weight, and therefore not considered to be an immunotoxic effect. No statistically significant alterations in either the mean relative spleen and thymus or absolute thymus weights were observed in treated male rats. No statistically significant differences in either the mean absolute or relative spleen and thymus weights were observed in treated female rats. Furthermore, glycolic acid did not produce test substance-related alterations in splenic or thymic histopathology at any dosage in either male or female rats following 90 days of exposure. Therefore, glycolic acid did not produce test substance-related adverse effects on the spleen or thymus weights of either male or female rats.

 

There were no statistically significant differences in the primary humoral immune response to Sheep Red Blood Cells (SRBC) for any glycolic acid treated male or female rats. A statistically significant decrease compared to control of 56% and 66%, respectively, in the primary humoral immune response to SRBC was observed for male and female rats dosed for six days with 20 mg/kg/day cyclophosphamide, the positive control material. Therefore, the SBC-specific ELISA test system was valid for this study with glycolic acid.

Justification for classification or non-classification

No classification for immunotoxicity required since no effects on the immune system were observed. On this basis, Glycolic acid does not warrant any classification according to Regulation (EC) No 1272/2008.