Sodium ascorbate

Carcinogenicity

Description of key information

The substance is not carcinogenic. The NOAEL was determined to be 2560 mg/kg bw/day.

Key value for chemical safety assessment

Carcinogenicity: via oral route

Link to relevant study records

Reference

Endpoint:

carcinogenicity: oral

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

comparable to guideline study

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 451 (Carcinogenicity Studies)

Deviations:

no

GLP compliance:

not specified

Species:

rat

Strain:

Fischer 344

Sex:

male/female

Route of administration:

oral: feed

Details on exposure:

PREPARATION OF DOSING SOLUTIONS:

DIET PREPARATION
- Rate of preparation of diet (frequency): at least once per week
- Mixing appropriate amounts with: Purina (TM) Lab Chow
- Storage temperature of food: 23°C

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

Standards were prepared at the 25,000-and 50,000-ppm levels by weighing appropriate amounts of ascorbic acid into a total of 1 gram of dosed feed. Standards were shaken by hand and vortexed to assure a good mix. Samples and standards were then extracted twice with 50-ml aliquots of deionized water. The combined supernatants were spiked with 1.0 mL of starch solution and titrated with 0.0884 N iodine solution. Each milliliter of the iodine solution is equivalent to 7.779 mg of ascorbic acid. Standards produced an average recovery of 100.8% & 3.8%. Analyses were performed in duplicate, and concentra- tions reported represent values corrected for recovery.

Duration of treatment / exposure:

103 weeks

Frequency of treatment:

daily

Post exposure period:

none

Dose / conc.:

0 mg/kg bw/day

Remarks:

control groups

Dose / conc.:

25 000 mg/kg diet

Remarks:

low dose groups

Dose / conc.:

50 000 mg/kg diet

Remarks:

high dose groups

No. of animals per sex per dose:

50

Control animals:

yes, concurrent no treatment

Positive control:

not needed

Observations and examinations performed and frequency:

CAGE SIDE OBSERVATIONS: Yes
- Time schedule: twice daily

DETAILED CLINICAL OBSERVATIONS: No data

BODY WEIGHT: Yes
- Time schedule for examinations: body weights by cage every week during the first 13 weeks, monthly thereafter. Mean bodoy weights were calculated by dividing the weight of teh group by the number of animals of the group.

FOOD CONSUMPTION AND COMPOUND INTAKE:
- Food consumption for each animal group determined and mean daily diet consumption calculated as g food/kg body weight/day: Yes
- Compound intake calculated as time-weighted averages from the consumption and body weight gain data: No

FOOD EFFICIENCY:
- Body weight gain in kg/food consumption in kg per unit time X 100 calculated as time-weighted averages from the consumption and body weight gain data: No



OPHTHALMOSCOPIC EXAMINATION: No

HAEMATOLOGY:No

CLINICAL CHEMISTRY: YNo

URINALYSIS: No

NEUROBEHAVIOURAL EXAMINATION: No

Sacrifice and pathology:

GROSS PATHOLOGY: Yes

HISTOPATHOLOGY: Yes

Statistics:

Probability of survival (Kaplan and Meier), tumor incidence data (Mantel and Haenszel); test of significance. Fisher's t-test; Cochran-Armitage test for dose-reponse trends

Clinical signs:

no effects observed

Dermal irritation (if dermal study):

not examined

Mortality:

no mortality observed

Description (incidence):

Survival of dosed and control female rats and of dosed and control female mice were comparable. Survival of high-dose male rats was slightly greater than that of the controls (P=0.087). Survival of high-dose male mice was significantly greater (P=0.009) than that of the controls.

Body weight and weight changes:

effects observed, treatment-related

Description (incidence and severity):

Throughout most of the study, mean body weights of dosed female rats and dosed female mice were lower than those of the controls. Final body weights were comparable among groups, except for the high-dose female rats (<13%); marginal differences (<8%) were observed for low-dose female rats and for dosed female mice (8%-11%).

Food consumption and compound intake (if feeding study):

no effects observed

Description (incidence and severity):

Food consumption was equivalent among groups.

Food efficiency:

not examined

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

not examined

Ophthalmological findings:

not examined

Haematological findings:

not examined

Clinical biochemistry findings:

not examined

Urinalysis findings:

not examined

Behaviour (functional findings):

not examined

Immunological findings:

not examined

Organ weight findings including organ / body weight ratios:

not examined

Gross pathological findings:

not specified

Neuropathological findings:

not examined

Histopathological findings: non-neoplastic:

no effects observed

Histopathological findings: neoplastic:

effects observed, non-treatment-related

Description (incidence and severity):

Most observational differences were confined to the female rat. The incidence of low-dose female rats with undifferentiated (mononuclear-cell) leukemias (control, 6/50, 12%; low-dose, 17/ 50, 34%; high-dose, 12/50, 24%) was significantly higher (P<0.02) than that in controls. These tumors were not considered to be related to administration of L-ascorbic acid because they did not occur in the female high-dose group at incidences significantly greater (P>0.07) than those in the controls, the trend test was not significant (P10.07), and no increases were observed for male rats.

Relevance of carcinogenic effects / potential:

These borderline increases and decreases in neoplastic lesions, as well as the decrease in non-neoplastic effects in female rats, were considered to be insufficient evidence for a compound-related effect.

Key result

Dose descriptor:

NOAEL

Effect level:

ca. 2 560 mg/kg bw/day (actual dose received)

Based on:

test mat.

Sex:

male

Basis for effect level:

other: no adverse effects observed

Key result

Dose descriptor:

NOAEL

Effect level:

ca. 3 050 mg/kg bw/day (actual dose received)

Based on:

test mat.

Sex:

female

Basis for effect level:

other: no adverse effects observed

Key result

Critical effects observed:

no

Conclusions:

Ascorbic acid was not carcinogenic for male and female rats and male and female mice.

Executive summary:

A carcinogenesis bioassay of L-ascorbic acid (>97%pure) was conducted by administering diets containing 25,000 or 50,000 ppm ascorbic acid to groups of 50 F344/N rats of each sex for 103 weeks. Controls consisted of 50 untreated rats of each sex. Fifty-thousand ppm is the highest dose recommended for chronic studies.

Survival of dosed and control female rats were comparable. Survival of high-dose male rats was slightly greater than that of the controls (P=0.087). Throughout most of the study, mean body weights of dosed female rats were lower than those of the controls. Final body weights were comparable among groups, except for the high-dose female rats (<13%); marginal differences (<8%) were observed for low-dose female rats. Food consumption was equivalent among groups. Most observational differences were confined to the female rat. The incidence of low-dose female rats with undifferentiated (mononuclear-cell) leukaemias (control, 6/50, 12%; low-dose,17/ 50, 34%; high-dose,12/50, 24%) was significantly higher (P<0.02) than that in controls. These tumours were not considered to be related to administration of L-ascorbic acid because they did not occur in the female high-dose group at incidences significantly greater (P>0.07) than those in the controls, the trend test was not significant (P10.07), and no increases were observed for male rats. Under the conditions of this bioassay, ascorbic acid was not carcinogenic for male and female F344/N rats. The NOAEL values are 2,560 mg/kg bw and day for male rats, and 3,050 mg/kg bw and day for female rats in this study, derived from the calculated mean dose of the high dose groups (NTP, 1983).

Additionally, a second carcinogenicity oral feed study with ascorbic acid at 25,000 and 50,000 ppm in the diet using male and female B6C3F1 mice was also conducted. The results were comparable (not described in detail in this dossier). Most notably, ascorbic acid was not carcinogenic for male and female mice. The NOAEL values are 12,788 mg/kg bw and day for male and 14,792 mg/kg bw and day for female mice, derived from the calculated mean dose of the high dose groups (NTP, 1983).

Both studies are considered to be valid and suitable for assessment of the endpoints repeated dose toxicity (see also the preceding rat and mouse 90-day studies) and genotoxicity.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

NOAEL

2 560 mg/kg bw/day

Study duration:

chronic

Species:

rat

Quality of whole database:

The quality of the data base is excellent as two fully valid ascorbic acid oral feed carcinogenicity studies in two species (rat and imouse) are available.
The result can be adopted for sodium ascorbate as this is the coresponding base to ascorbic acid. A detailed justification for read across has been provided.

Justification for classification or non-classification

Classification, Labelling, and Packaging Regulation (EC) No 1272/2008

The available experimental test data are reliable and suitable for classification purposes under Regulation (EC) No 1272/2008. The data did not indicate carcinogenic properties of the test substance. Based on available data on carcinogenicity, the test item is not classified according to Regulation (EC) No 1272/2008 (CLP), as amended for the tenth time in Regulation (EU) No 2017/776.

Additional information

Two fully valid oral feed carcinogenesis studies of ascorbic acid were conducted using rats and mice (50 animals per sex and dose in each of the studies). The study period was 103 weeks, the doses were 25,000 and 50,000 ppm in the diet. No adverse effects, neoplastic or non-neoplastic, were seen in either study. Therefore, the maximum ingested dose corresponds to the NOAEL value which was 2,560 and 3,050 mg/kg bw and day in the male and female rat, and 12,788 and 14,792 mg/kg bw and day in the male and female mouse. Ascorbic acid was not carcinogenic in the F344 rat and in the B6C3F1 mouse (NTP, 1983).

This result can be adopted to the corresponding base, the ascorbate anion, and hence to sodium ascorbate. Taking the molecular weights into consideration, this corresponds to 3200 mg/kg bw for the male and 3812 mg/kg bw and day for the female rat.