Morpholinium sulphamate

Endpoint summary

Description of key information

The subacute toxicity oral of morpholinium sulphamate was assessed in a read across approach. The oral toxicity study with morpholine was considered as a worst-case approach for the assessment of oral toxicity of morpholinium sulphamate after repeated administration. The LOAEL of 500 mg morpholine/kg bw/day was considered as the appropriate LOAEL for morpholinium sulphamate.

Key value for chemical safety assessment

Repeated dose toxicity: via oral route - systemic effects

Endpoint conclusion

Endpoint conclusion:

adverse effect observed

Dose descriptor:

LOAEL

500 mg/kg bw/day

Study duration:

subchronic

Species:

rat

Quality of whole database:

4 publication and one non GLP-study were available

Repeated dose toxicity: inhalation - systemic effects

Endpoint conclusion

Endpoint conclusion:

no study available

Repeated dose toxicity: inhalation - local effects

Endpoint conclusion

Endpoint conclusion:

no study available

Repeated dose toxicity: dermal - systemic effects

Endpoint conclusion

Endpoint conclusion:

no study available

Repeated dose toxicity: dermal - local effects

Endpoint conclusion

Endpoint conclusion:

no study available

Additional information

Repeated dose toxicity: oral

For the assessment of the oral toxicity after repeated administration of morpholinium sulphamate several repeated dose toxicity studies conducted with morpholine, ammonium sulphamate and morpholinium sulphamate were considered.

Morpholine

In a repeated dose toxicity study (Sander & Bürkle, 1969) morpholine was administered on female Sprague-Dawley rats orally by feed for eight weeks. The daily uptake average was 500 mg/kg bw. This dosage did not cause mortality within the entire study period. After 270 days moderate adiposis of the liver was observed. No further macroscopic or microscopic alterations were noted. Therefore, the LOAEL was determined to be 500 mg/kg bw/day.

In a subchronic toxicity study morpholine oleic acid salt (MOAS) was applied to mice for 13 weeks (Shibata et al., 1987). The dose levels of MOAS used were 0%, 0.15%, 0.3%, 0.6%, 1.25%, and 2.5% in drinking water (corresponds roughly to 0, 70, 140, 200, 400, and 700 mg morpholine/kg bw/day).

Impairment of renal activity was observed at doses above 200 mg morpholine/kg bw/day as indicated by the significant elevation of specific gravity of the urine and of plasma urea nitrogen. The relative weight of the kidneys showed a dose-dependent increase that was statistically significant at dose levels equivalent to 400 and 700 mg morpholine/kg bw/day in both sexes. Except for cloudy swelling of the proximal tubules of the kidneys in mice on the 700 mg morpholine/kg bw/day regimen, no treatment-related histopathological alterations were observed in organs of either sex. Based on the experimental data the No-observed-adverse effect level was determined to be 140 mg morpholine/kg bw/day when administered in drinking water to mice.

The subacute oral toxicity of Morpholine in rats was evaluated (Shea, 1939). The substance was administered for 30 consecutive days at dose levels of 160, 320, 800 mg/kg bw/day to three groups of rats (20 rats per group). 2 mL of the test item preparation were administered by stomach tube. Except of one rat, all animals of the 800 mg/kg bw/day dose group died during the entire study period. Observations of rats treated with 800 mg/kg included: lethargy, weight loss, "shock", intense irritation of the intestinal tract, and congestion of the stomach wall and membrane. Microscopic changes in the liver included cloudy swelling, marked congestion, haemorrhage, necrosis, and an increase in Kupffer and connective tissue cells. The kidneys had tubular congestion, degeneration, swelling and necrosis: desquamation of the epithelium was also noted. The spleens of the 800 mg/kg group had congestion and an increase in splenocytes and hemosiderin deposits. Necrosis of the epithelium and capillary congestion was observed in the stomach. The lungs had congestion and alveolar desquamation.

In rats exposed to 320 mg/kg bw/day, 12 animals survived. Eight of the surviving animals gained weight. Gross pathologic changes included congestion of the stomach and lung. Microscopic examination of tissues from 5 rats revealed comparable changes as seen in the 800 mg/kg bw/day dose group. In the 160 mg/kg bw/day dose group 12 of 20 rats survived. No gross pathologic changes were noted. Microscopic changes were assessed in 3 rats of this group. Changes in the liver included congestion, swelling, and a marked increase in Kupffer, interstitial and connective tissue cells. Congestion and cloudy swelling with areas of necrosis and desquamation were noted in the kidney. Evaluation of the stomach revealed necrosis of the mucous membrane. The spleens appeared normal. Based on the experimental results, no No-observed-adverse-effect-level could be determined. The Lowest-observed-adverse effect level after oral administration by a stomach tube is 160 mg/kg bw/day.

 

Ammonium sulphamate

A 90-day oral repeated dose toxicity study on adult female rats and male/female weanlings was conducted with ammonium sulphamate (Gupta et al., 1979). The test substance was administered orally at dose levels of 100 (group 2), 250 (group 3) and 500 mg/kg bw/day (group 4) 6 days a week. The first group received distilled water and served as control.

No adverse effect was observed regarding appearance, behaviour or survival of animals. In the case of adult rats (group 4), the body weight was significantly decreased compared to controls after the end of 60 days. No significant changes in relative organ weights were observed. Hematological examination revealed non-significant increase in the neutrophils in the adults and male weanling rats (group 4) after 90 days. Histopathological alteration was observed in one adult animal of group 4 showing slight fatty degenerative changes in the hepatic cytoplasm after 90 days. Based on these results the NOAEL was determined to be 500 mg/kg bw/day.

 

Morpholinium sulphamate

The aim of a 14-Day toxicity study (Toxi Coop, 2012) was to obtain first information on the toxic potential of morpholinium sulphamate in rats at three dose levels to allow a dose-setting for a Reproduction/ Developmental Toxicity Screening Test (main study).

The test item was administered orally (by gavage) to Hsd.Brl.Han: Wistar rats (n=5 animals/sex/dose) once a day at 0 (vehicle control), 100, 300 and 1000 mg/kg bw/day doses applied in concentrations of 50, 150 and 500 mg/mL, corresponding to a dose volume of 2 mL/kg bw for 14 days.

Analytical control of dosing formulations was performed once during the study. The measured concentrations ranged between 90 % to 110 % of nominal concentrations. The suitability of the chosen vehicle for the test item was analytically proven. Recovery was between 101 and 102 % of nominal concentrations at 1 and 500 mg/mL in water, respectively. Morpholinium sulphamate proved to be stable at room temperature for two days and at 5 +/- 3°C for 3 days. Detailed clinical observations were made on all animals once a day, after treatment at approximately the same time. Body weight and food consumption were measured weekly. Clinical pathology and gross pathology examinations were conducted at the end of the treatment period. Selected organs were weighed. The results were interpreted comparing treatment groups with respect to controls, which were treated concurrently with vehicle (distilled water) only.

No test item mortality occurred at any dose level (1000, 300 and 100 mg/kg bw/day) during the observation period. Test item related salivation appeared in male and female animals dosed with 1000 mg/kg bw/day. There were no test item-related effects on the body weight although the body weight gain was slightly less in male and female animals at 1000 mg/kg bw/day with respect to the control group during the first week. The mean daily food consumption was less than in the control in female animals dosed with 1000 mg/kg bw/day during week 1.

The mean blood coagulation parameters (activated partial thromboplastin time and prothrombin time) were slightly but significantly lower in the male animals dosed with 1000 mg/kg bw/day with respect to the control group. However, as this slight reduction was only observed in the male species with no further dose dependency observable, it was not considered to be of toxicological relevance. Furthermore, there were no test item related changes in the remaining hematological parameters.

Clinical chemistry examinations revealed significantly higher mean concentrations of serum bile acids in female animals at 1000 mg /kg bw/day. Specific macroscopic alterations related to the test item were not found during the necropsy. There were no test item related changes in the examined organ weights.

Based on these observations the doses for a Reproduction/Developmental Toxicity Screening Test (main study) were determined to be 0, 100, 300 and 1000 mg/kg bw/day.

Under the conditions of the reproduction toxicity screening test (Toxi Coop, 2012) morpholinium sulphamate did not cause toxic changes and did not influence male and female reproductive performance (gonad function, mating behavior, conception, pregnancy, parturition) in parental male and female Hsd.Brl.Han: Wistar rats or development of the F1 offspring from conception to day 4 post-partum after repeated dose oral administration at 100, 300 or 1000 mg/kg bw/day. Based on these observations the No Observed Adverse Effect Levels (NOAEL) were determined to be 1000 mg/kg bw/day for male and female animals as well as for the offspring.

Conclusion

When morpholine was added to feed (Sander & Bürkle, 1969) or was administered as morpholinium salt (Shibata, 1987) no mortality occurred. During feed preparation dissociation of morpholine to morpholinium salts (e.g. with fatty acids as counterions) was expected.

In contradiction in the subacute toxicity study (Shea, 1939) morpholine was administered by a stomach tube. This form of application causes mortality in each dose group (160, 320 and 800 mg/kg bw/day). Based on these results the adverse effects of morpholine in its undissociated form (Shea, 1939) were associated to the strong basic character of the substance. In case of the feeding studies (Shibata, 1987 and Shea, 1939) morpholine in its dissociated form was expected to be systemically available to the rats.

As the repeated dose toxicity study published by Sander & Bürkle (1969) was regarded as the most suitable for the hazard assessment of morpholinium salts after repeated oral administration due to the study design used (test item, common animal species and route of administration) the LOAEL of 500 mg morpholine/kg bw/day was considered as the appropriate effect level for morpholinium salts.

In the 90 day repeated dose study with ammonium sulphamate in rats up to a dose level of 500 mg/kg bw/day (Gupta et al., 1979) no mortality occurred and no adverse effects were observed. As ammonium sulphamate was dissolved in distilled water before oral administration, dissociation of the test item into the ammonium cation and the sulphamidic anion is expected, which were systemically available. The NOAEL was determined to be 500 mg/kg bw/day and was considered as the appropriate NOAEL for sulphamate.

Morpholinium sulphamate itself did not induce mortality or any other macroscopic or microscopic alterations on reproductive organs and tissues when orally administered on rats for approximately 42 days up to a dose level of 1000 mg/kg bw/day (Toxi Coop, 2012).

Generally, based on the chemical structure dissociation of morpholinium sulphamate into morpholinium cation and sulphamidic anion is expected. This assumption is supported by Gupta et al. (1979) who stated that ammonium sulphamate might readily dissociated in the body into its biodegradable ammonium and sulphate radicals which then enter the general metabolic tool of the organism.

Due to the dissociation of the test item consideration of repeated dose toxicity studies conducted with only one part of the test item is justified. It is concluded that the administration of morpholinium sulphamate would not result in any other adverse effects than those described above. This assumption is supported by the results of the reproductive toxicity screening test (Toxi Coop, 2012) which did not revealed any adverse effects up to a dose level of 1000 mg morpholinium sulphamate/kg bw/day. Therefore, the oral toxicity study with morpholine was considered as a worst-case approach for the assessment of oral toxicity of morpholinium sulphamate after repeated administration. The LOAEL of 500 mg morpholine/kg bw/day was considered as the appropriate LOAEL for morpholinium sulphamate.

Repeated dose toxicity: inhalation

In accordance with column 2 of REACH Annex IX, the test repeated dose toxicity after inhalation (required in section 8.6) does not need to be conducted as repeated dose toxicity studies for oral application are available or will be proposed. In addition, the volatility of the substance is considered to be low and inhalation exposure is in conclusion expected unlikely. Thus, no test on repeated dose inhalation toxicity has to be conducted and risk assessment is based on the oral studies.

Repeated dose toxicity: dermal

In accordance with column 2 of REACH Annex IX, the test repeated dose toxicity after dermal application (required in section 8.6) does not need to be conducted as repeated dose toxicity studies for oral application are available. Thus, no test on repeated dose dermal toxicity has to be conducted and risk assessment is based on the oral studies.

 

Justification for selection of repeated dose toxicity via oral route - systemic effects endpoint:
Read-across approach was applied. For read across justification please refer to IUCLID section 13.

Justification for classification or non-classification

Based on the results of the sub acute repeated oral toxicity study, the test item was not classified and labelled according to Directive 67/548/EEC (DSD) and to Regulation 1272/2008 (CLP).